200_Seeley's Essentials of Anatomy and Physiology, 9th Ed-690

Development, Heredity, and Aging 573

Ruptured Before parturition, the progesterone concentration in the mother’s
amnion blood has reached its highest level. Progesterone has an inhibitory
1 First stage. The cervix dilates, and the effect on uterine smooth muscle cells. However, estrogen levels
amnion ruptures. continually increase in the maternal circulation, exciting uterine
smooth muscle. Thus, the inhibitory influence of progesterone on
Placenta smooth muscle is overcome by the stimulatory effect of estrogen
near the end of pregnancy.
The fetus also plays a role in stimulating parturition. Stress
on the fetus triggers the secretion of a releasing hormone from
the fetal hypothalamus, which in turn causes adrenocorticotropic
hormone (ACTH) to be released from the fetal anterior pituitary.
ACTH stimulates the fetal adrenal gland to secrete hormones from
the adrenal cortex that reduce progesterone secretion, increase
estrogen secretion, and increase prostaglandin production by the
placenta. Prostaglandins strongly stimulate uterine contractions.
During parturition, stretching of the uterine cervix initiates
nervous reflexes that cause the mother’s posterior pituitary gland to
release oxytocin. Oxytocin stimulates uterine contractions, which
move the fetus farther into the cervix, causing further stretch. A
positive-feedback mechanism is established. This positive-feedback
mechanism stops after delivery, when the cervix is no longer stretched.

2 Second stage. The fetus is expelled from the uterus. 20.3 The Newborn
Uterus
Learning Outcome After reading this section, you should be able to
Placenta Umbilical cord
A. Discuss the respiratory, circulatory, and digestive changes
3 Third stage. The placenta is expelled. that occur in the newborn at the time of birth.

Process Figure 20.14 Parturition The newborn, or neonate (nē′ ō-nāt; newborn), experiences sev-
eral dramatic changes at the time of birth. The major and earliest
During the 4 or 5 weeks following parturition, the uterus changes are the separation of the infant from the maternal circula- Reproductive
becomes much smaller, but it remains somewhat larger than it tion and the transfer from a fluid to a gaseous environment.
was before pregnancy. A vaginal discharge composed of small
amounts of blood and degenerating endometrium can persist for Respiratory and Circulatory Changes
several weeks after parturition.
The precise signal that triggers parturition is unknown, but The large, forced gasps of air that occur when an infant cries at
many factors that support it have been identified (figure 20.15). the time of delivery help inflate the lungs. The fetal lungs produce
a substance called surfactant (ser-fak′ tănt), which coats the inner
surface of the alveoli, reduces surface tension in the lungs, and
allows the newborn lungs to inflate (see chapter 15).
Surfactant is not manufactured in the fetal lungs before about
6 months after fertilization. If a fetus is born before the lungs can
produce surfactant, the surface tension inside the lungs is too great
for the lungs to inflate. Under these conditions, the newborn may
die of respiratory distress. Therefore, premature newborns are
treated with bovine or synthetic ­surfactant.
The initial inflation of the lungs causes important changes in
the cardiovascular system (figure 20.16). Expansion of the lungs
reduces the resistance to blood flow through the lungs, resulting in
increased blood flow from the right ventricle of the heart through
the pulmonary arteries. Consequently, an increased amount of blood
flows from the right atrium to the right ventricle and into the pul-
monary arteries, and less blood flows from the right atrium through
the foramen ovale to the left atrium. The reduced resistance to blood
flow through the lungs and the increasing volume of blood returning
from the lungs through the pulmonary veins to the left atrium make
the pressure in the left atrium greater than that in the right atrium.
This pressure difference forces blood against the interatrial septum,
closing a flap of tissue that develops in that region over the foramen

574 Chapter 20

1 The fetal hypothalamus secretes a Uterine stretch Maternal
releasing hormone that stimulates stimulates hypothalamus
adrenocorticotropic hormone (ACTH)
secretion from the pituitary. The fetal sensory neurons. Maternal
pituitary secretes ACTH in greater 5 posterior
amounts near parturition. pituitary
2 Adrenal Progesterone
2 ACTH causes the fetal adrenal gland to cortical steroids synthesis 6
secrete greater quantities of adrenal levels off. Oxytocin
cortical steroids. 3
4
3 Adrenal cortical steroids travel in the ACTH Estrogen and
umbilical blood to the placenta. from fetal prostaglandin
pituitary synthesis
4 In the placenta, the adrenal cortical 1 increases.
steroids cause progesterone synthesis to Releasing hormone from
level off and estrogen and prostaglandin fetal hypothalamus Placenta
synthesis to increase, making the uterus Stress
more excitable. 7
Uterine smooth
5 The stretching of the uterus produces muscle contractions
action potentials that are transmitted to
the brain through ascending pathways.

6 Action potentials stimulate the secretion of
oxytocin from the mother’s posterior
pituitary.

7 Oxytocin causes the uterine smooth
muscle to contract.

Process Figure 20.15  Factors That Influence Parturition

Although the precise control of parturition in humans is unknown, these changes appear to play a role.

Reproductive ovale. This action completes the separation of the heart into two and the shock of birth, the neonate usually loses 5–10% of its
pumps: the right side and the left side of the heart. total body weight during the first few days of life. Although the
A short artery, the ductus arteriosus (ar-tēr′ ē-ō-sŭs), connects digestive system of the fetus becomes somewhat functional late
the pulmonary trunk to the aorta. Before birth, the ductus arteriosus in development, it is still very immature in c­ omparison to that of
carries blood from the pulmonary trunk to the aorta, bypassing the the adult and can digest only a limited number of food types. The
fetal lungs. This artery closes off shortly after birth, forcing blood to newborn digestive system is capable of digesting lactose (milk
flow through the lungs. sugar) from the time of birth. The pancreatic secretions are suffi-
Also before birth, the deoxygenated fetal blood passes to the ciently mature for a milk diet, but the digestive system only gradu-
placenta through umbilical (ŭm-bil′ i-kăl) arteries, which originate ally develops the ability to digest more solid foods over the first
in the internal iliac arteries. As the blood passes through the pla- year or two. New foods should therefore be introduced gradually
centa, nutrient and waste exchange occurs between the fetal blood during the first 2 years. Parents are also advised to introduce only
and the maternal blood. Oxygenated fetal blood then returns to the one new food at a time, so that, if an allergic reaction occurs, the
fetus through an umbilical vein. The umbilical vein passes through cause is more easily determined.
the liver but bypasses the sinusoids of the liver by way of the Amylase secretion by the salivary glands and the pancreas
ductus venosus (vē-nō′ sŭs) and joins the inferior vena cava. When remains low until after the first year. Lactase activity in the small
the umbilical cord is tied and cut, no more blood flows through the intestine is high at birth but declines during infancy, although the
umbilical vein and arteries, and they degenerate. The remnant of levels still exceed those in adults. In many adults, lactase activity is
the umbilical vein becomes the round ligament of the liver. lost, and an intolerance to milk develops.

Digestive Changes 20.4  Lactation

Late in gestation, the fetus swallows amniotic fluid from time to Learning Outcome After reading this section, you should be able to
time. Shortly after birth, this swallowed fluid plus cells sloughed
from the mucosal lining of the digestive tract, mucus produced by A. Describe the events of lactation.
intestinal mucous glands, and bile from the liver are eliminated as
a greenish anal discharge called meconium (mē-kō′ nē-ŭm). Lactation (lak-tā′ shŭn) is the production of milk by the mammary
After birth, the neonate is suddenly separated from its source glands (figure 20.17). It normally occurs in women following par-
of nutrients, the maternal circulation. Because of this separation turition and may continue for up to 2 or 3 years.

Development, Heredity, and Aging 575

1 Blood bypasses the lungs Superior vena cava 1
by flowing from the pulmonary Aortic arch 2
trunk through the ductus Ductus arteriosus
arteriosus to the aorta.
Pulmonary trunk
2 Blood also bypasses the
lungs by flowing from the Foramen ovale
right to the left atrium through
the foramen ovale.

3 Blood bypasses the liver Inferior vena cava 3 Abdominal
sinusoids by flowing through Liver aorta
the ductus venosus. Ductus
venosus

4 Oxygenated blood from Hepatic 4 Kidney
the placenta is passed to the portal vein 5
fetus by the umbilical vein. Umbilical vein Common iliac
Fetal umbilicus artery
5 Deoxygenated blood is Internal iliac
carried from the fetus to Umbilical cord arteries
the placenta through the
umbilical arteries.

(a) Umbilical arteries

P(ar)ocess Figure 20.16  Circulation in the Fetus and Newborn

(a) Circulatory conditions in the fetus.

During pregnancy, the high concentration and continuous (figure 20.17). For the first few days following parturition, the Reproductive
presence of estrogen and progesterone cause expansion of the duct mammary glands secrete colostrum (kō-los′ trŭm), a high-protein
system and the secretory units within the breast. Other hormones, material that contains many antibodies. Although colostrum is
including a prolactin-like hormone produced by the placenta, help high in proteins, it contains little fat and less lactose than milk.
support the development of the breasts. Also, additional adipose Eventually, milk with a higher fat and lactose content is produced.
tissue is deposited; thus, the size of the breasts increases through- Colostrum and milk provide nutrition and antibodies that help
out pregnancy. Estrogen and progesterone prevent the secretory protect the baby from infections.
part of the breast from producing milk during pregnancy. At the time of breastfeeding, milk contained in the alveoli and
Blood levels of estrogen and progesterone fall dramatically ducts of the breast is forced out of the breast by contractions of
after parturition. Once the placenta has been dislodged from the cells surrounding the alveoli. Suckling produces action potentials
uterus, the source of these hormones is gone. After parturition, in that are carried to the hypothalamus, where they cause the release
the absence of estrogen and progesterone, prolactin produced by of oxytocin from the posterior pituitary (figure 20.17). Oxytocin
the anterior pituitary stimulates milk production. During suckling, stimulates cells surrounding the alveoli to contract. As a result,
sensory action potentials are sent from the nipple to the brain, milk flows from the breasts, a process called milk letdown.
stimulating the release of prolactin from the anterior pituitary Higher brain centers can also cause the release of oxytocin as a

576 Chapter 20

1 When air enters the lungs, blood is Superior 1
forced through the pulmonary vena cava 2
arteries to the lungs. The ductus Aortic arch
arteriosus closes (gray). 3
Closed ductus arteriosus 4

Pulmonary 5
trunk

2 The foramen ovale closes and Fossa ovalis
becomes the fossa ovalis. Blood (foramen
can no longer flow from the right to ovale closed)
the left atrium. Inferior vena cava

3 The ductus venosus degenerates Liver Abdominal
and becomes the ligamentum Ligamentum aorta
venosum (gray). venosum Kidney
(degenerated
ductus Common
venosus) iliac artery
Internal iliac
4 The umbilical arteries and vein Hepatic arteries
are cut. The umbilical vein portal vein
becomes the round ligament of Round ligament
the liver (gray). of liver
(degenerated umbilical vein)
5 The umbilical arteries also Umbilicus
degenerate (gray).
Degenerated
(b) umbilical arteries

Process Figure 20.16  (continued)

(b) Circulatory changes that occur after birth.

Reproductive result of a conditioned reflex in response to such stimuli as hearing A great number of changes occur in the infant from the time of
an infant cry or thinking about breastfeeding. birth until 1 year of age. The time when these changes occur may
Repeated stimulation of prolactin release makes breastfeeding vary considerably from child to child, and the dates given are only
possible for several years. If breastfeeding is stopped, prolactin rough estimates. The brain is still developing at this time, and
release stops, and within a few days the breasts’ ability to respond much of what the infant can accomplish depends on the amount
to prolactin is lost, and milk production ceases. of brain development achieved. It is estimated that the newborn’s
central nervous system contains nearly all the adult number of
Predict 5 neurons, but subsequent growth and maturation of the brain add
While breastfeeding her baby, a woman felt cramps in her new neuroglial cells, new myelin sheaths, and new connections
abdomen. Explain what was happening. between neurons, which may continue throughout life.
By 6 weeks, the baby is usually able to hold up her head
20.5 First Year Following Birth when placed in a prone position and begins to smile in response to
people or objects. At 3 months of age, the infant exercises his limbs
Learning Outcome After reading this section, you should be able to aimlessly. However, he can control his arms and hands enough
that voluntary thumb sucking can occur. The infant can follow a
A. Describe the changes that occur during the first year after birth.

Development, Heredity, and Aging 577

PROCESS Figure 20.17 Hormonal Control of Lactation

Hypothalamus
2

1 Stimulation of the nipple by the
baby’s suckling initiates action
potentials in sensory
neurons that connect with the
hypothalamus.

2 In response, the hypothalamus Posterior Anterior
stimulates the posterior pituitary pituitary
pituitary to release oxytocin and
the anterior pituitary to release Spinal
prolactin. cord

3 Oxytocin stimulates milk release Oxytocin Oxytocin Prolactin
from the breast. Prolactin stimulates Prolactin (milk letdown) (milk production)
additional milk production. 3

1

Mammary
gland

moving person with his eyes. At 4 months, the infant begins to do more than 20% will be older than 65. The average life expectancy in Reproductive
push-ups—that is, raise himself by the arms. The infant can begin 1900 was about 47 years, in 1940 it was about 63 years, and today
to grasp objects placed in his hands, coo and gurgle, roll from back it is about 78 years. In 1900, nearly 70% of all males over age 65
to side, listen quietly when hearing a person’s voice or music, hold were still working; today, only about 20% are still working past
the head erect, and play with his hands. At 5 months, the infant can age 65. Though older people are more likely to be retired today,
usually laugh out loud, reach for objects, turn her head to follow they are healthier and more active than in past generations. Instead
an object, lift her head and shoulders, sit with support, and roll of working, older people may be enjoying the later stages of life by
over. At 8 months, the infant can recognize familiar people, sit up participating in recreational activities.
without support, and reach for specific objects. At 12 months, the
infant may pull herself to a standing position and may be able to The stages of life from fertilization to death are divided into
walk without support. The child can pick up objects in her hands three prenatal stages and five postnatal stages as follows:
and examine them carefully. A 12-month-old child can understand
much of what is said and may say several words. 1. Germinal (jer′mi-năl) period, fertilization to 14 days
2. Embryo, 14–56 days after fertilization
20.6 LiFE stAGEs 3. Fetus, 56 days after fertilization to birth
4. Neonate, birth to 1 month after birth
learning Outcomes After reading this section, you should be able to 5. Infant (in′fănt), 1 month to 1 or 2 years after birth (the end

A. List the stages of life, and describe the major events of infancy is sometimes set at the time that the child begins
associated with each stage. to walk)
6. Child, 1 or 2 years old to puberty (about 11–14 years)
B. Describe the process of aging. 7. Adolescent (ad-ō-les′ent), teenage years, from puberty to
C. Describe the events that occur at the time of death. 20 years old
8. Adult, 20 years old to death
The stages of life and the activities associated with those stages are
issues of great interest in today’s society. We view life stages very Adulthood is sometimes divided into three periods: young adult,
differently today than we did in the past. For example, in 1960, 20% 20–40 years old; middle age, 40–65 years old; and older adult,
of males and 12% of females graduating from high school attended or senior citizen, 65 years old to death. Much of this designation is
college. Today, over half of all people 25 and older have attended associated more with social norms than with physiology.
college for some period of time. In addition, there are many more
nontraditional college students than there were just a few years ago. During childhood, the individual grows in size and develops
considerably. Many of the emotional characteristics a person pos-
In 1900, only 5% of the U.S. population was over age 65. sesses throughout life are formed during early childhood.
Today, about 16% of the population is over age 65, and by 2030
Major physical and physiological changes occur during ado-
lescence, and many of these changes also affect the emotions and

578 Chapter 20

Reproductive behavior of the individual. Other emotional changes occur as the The heart loses elastic recoil ability and muscular contractility.
adolescent attempts to fit into an adult world. Puberty (pū′ ber-tē) As a result, total cardiac output declines, and less oxygen and
is the time when reproductive cells begin to mature and when fewer nutrients reach the body cells supplied by the cardiovascular
gonadal hormones are first secreted in substantial amounts. These system. This decline in blood flow can be particularly harmful to
hormones stimulate the development and maturation of secondary cells that require high oxygen levels, such as neurons of the brain,
sexual characteristics, such as enlargement of the female breasts and cells that are already compromised, such as cartilage cells of
and growth of body hair in both sexes. Puberty usually begins the joints, contributing to the general decline in these tissues.
in females at about 11–13 years of age and in males at about Reduced cardiac function also can result in decreased blood
12–14 years of age. The onset of puberty is usually accompanied flow to the kidneys, contributing to decreases in the kidneys’
by a growth spurt, followed by a period of slower growth. Full filtration ability. Degeneration of the connective tissues as a result
adult stature is usually achieved before age 17 or 18 in females of collagen cross-linking and other factors also decreases the fil-
and before age 19 or 20 in males. tration efficiency of the glomerular basement membrane.
Arteriosclerosis (ar-tēr′ ē-ō-skler-ō′ sis) is general hardening of
The Aging Process the arteries affecting mainly arterioles. Atherosclerosis (ath′ er-ō-
skler-ō′ sis) is the gradual formation of lipid-containing plaques in
Development of a new human being begins at fertilization, and so the arterial wall of large and medium-sized arteries (see chapter 13).
does the process of aging. Cell division occurs at an extremely rapid These plaques then may become fibrotic and calcified, resulting
rate during early development and then begins to slow as various in arteriosclerosis. Atherosclerosis interferes with normal blood
cells become committed to specific functions within the body. flow and may result in a thrombosis (throm-bō′ sis), the formation
Many cells of the body, such as skin cells, continue to divide of a clot or plaque inside a vessel. An embolus (em′ bō-lŭs; a
throughout life, replacing dead or damaged tissue. But other cells, patch) is a piece of a clot that has broken loose and floats through
such as mature neurons in the brain, cease to divide. Dead neurons the circulation. An embolus can lodge in smaller arteries and
tend not to be replaced. After the number of neurons reaches a cause heart attacks or strokes. Although atherosclerosis affects all
peak (at approximately the time of birth), the number begins to middle-aged and elderly people to some extent and can even occur
decline. Neuronal loss is most rapid early in life and then decreas- in young people, some people appear more at risk because of high
es to a slower, steady rate. blood cholesterol levels. This condition seems to have a hereditary
Young embryonic tissue has relatively small amounts of col- component, and blood tests are available to screen people for high
lagen, and the collagen that is present is not highly cross-linked, blood cholesterol levels.
making it very flexible and elastic. However, many of the collagen Many other organs, including the liver, pancreas, stomach,
fibers produced during development are permanent components of and colon, undergo degenerative changes with age. The ingestion
the individual. As the individual ages, more and more cross-links of harmful agents can accelerate such changes. Examples of these
form between the collagen molecules, rendering the tissues more types of accelerated changes are the degenerative changes induced in
rigid and less flexible. the lungs (aside from lung cancer) by cigarette smoke and sclerotic
The tissues with the highest collagen content and the greatest changes in the liver resulting from excessive alcohol consumption.
dependency on collagen for their function are the most severely In addition to the previously described changes, cellular wear
affected by the collagen cross-linking and tissue rigidity associ- and tear, or cellular aging, contributes to aging. Progressive damage
ated with aging. One of the first structures to exhibit age-related from many sources, such as radiation and toxic substances, can
changes as a result of this increased rigidity is the lens of the result in irreversible cellular insults and may be one of the major
eye. Seeing close objects becomes more difficult with advancing factors leading to aging. Although the data are mixed and their
age until most middle-aged people require reading glasses (see interpretation is controversial, some studies suggest that ingesting
chapter 9). Loss of elasticity also affects other tissues, including moderate amounts of vitamins E and C in combination may help
the joints, kidneys, lungs, and heart, and greatly reduces their slow aging by stimulating cell repair. Vitamin C also stimulates
functional ability. collagen production and may slow the loss of tissue elasticity
As with nervous tissue, the number of skeletal muscle fibers associated with aging collagen.
declines with age. The strength of skeletal muscle reaches a peak According to the free radical theory of aging, free radicals,
between 20 and 35 years of life and usually declines steadily which are atoms or molecules with an unpaired electron, can
thereafter. Skeletal muscle strength depends primarily on the size react with and alter the structure of molecules that are critical for
of the muscle fibers, but the total number of fibers is probably normal cell function. Alteration of these molecules can result in
also important to muscle strength. As most people age, both the cell dysfunction, cancer, or other types of cellular damage. Free
number of fibers and the size of each tend to decline. The decline radicals are produced as a normal part of metabolism and are
in muscle fiber size may be more related to a general decrease in introduced into the body from the environment through the air we
activity than to any specific age-related changes. Like the colla- breathe and the food we eat. The damage caused by free radicals
gen of connective tissue, however, the macromolecules of skeletal may accumulate with age. Antioxidants, such as beta carotene
muscle cells undergo biochemical changes during aging, rendering (provitamin A), vitamin C, and vitamin E, can donate electrons to
the muscle tissue less functional. A good exercise program can free radicals without themselves becoming harmful. Thus, antioxi-
slow or even partially reverse the process of muscular aging. dants may prevent the damage caused by the free radicals and may
Cardiac muscle cells also do not normally divide after birth. ward off age-related disorders ranging from wrinkles to cancer.
Age-related changes in cardiac muscle cell function probably Again, the data are mixed and their interpretation is controversial.
contribute to a decline in cardiac function with advancing age.

Development, Heredity, and Aging 579

One characteristic of aging is an overall decrease in ATP 20.7  Genetics
production. This decline is associated with a decrease in oxidative
phosphorylation, which has been shown in many cases to be asso- Learning Outcomes After reading this section, you should be able to
ciated with mitochondrial DNA mutations.
Immune system changes may also be a major contributing factor A. Define genetics, and explain how chromosomes are related
to aging. The aging immune system loses its ability to respond to inheritance.
to outside antigens and begins to be more sensitive to the body’s
own antigens. Immune responses to one’s own tissues can result B. Describe the major types of inheritance.
in the degeneration of the tissues and may be responsible for such
conditions as arthritic joint disorders, chronic glomerulonephritis, Genetics is the study of heredity—that is, the characteristics chil-
and hyperthyroidism. In addition, T lymphocytes tend to lose their dren inherit from their parents. Many of a person’s characteristics,
functional capacity with aging and cannot destroy abnormal cells including specific abilities, susceptibility to certain diseases, and
as efficiently. This change may be one reason that certain types of even lifespan, are influenced by heredity. The functional units of
cancer occur more frequently in older people. heredity are genes, which are carried on chromosomes.
One of the greatest disadvantages of aging is the increasing
lack of ability to adjust to stress. Homeostasis is far more precari- Chromosomes
ous in elderly people, and eventually the body encounters some
stressor so great that the body’s ability to recover is surpassed and Deoxyribonucleic (dē-oks′ ē-rı̄′ bō-noo-klē′ ic) acid (DNA) mole-
death results. cules and their associated proteins become visible as densely stained
bodies, called mitotic chromosomes (krō′ mō-sōmz), during cell
Death division (see chapter 3). Somatic (sō-mat′ ik) cells, all the cells of
the body except the sex cells, contain 23 pairs of chromosomes, or
Death is usually not attributed to old age. Some other problem, 46 total chromosomes. The sex cells, or gametes (gam′ ētz), contain
such as heart failure, renal failure, or stroke, is usually listed as 23 unpaired chromosomes.
the cause of death. A karyotype (kar′ ē-ō-tı̄p) is a display of the chromosomes
Death was once defined as the loss of heartbeat and respira- in a somatic cell (figure 20.18; see chapter 3). There are 22 pairs
tion. In recent years, however, more precise definitions of death of autosomal (aw-tō-sō′ măl) chromosomes, which are all the
have been developed because both the heart and the lungs can chromosomes except the sex chromosomes, and there is one pair
be kept working artificially, as occurs during cardiopulmonary of sex chromosomes. A normal female has two X chromosomes
resuscitation, and the heart can even be temporarily replaced by an (XX) in each somatic cell, whereas a normal male has one X and
artificial device. Modern definitions of death are based on the per- one Y chromosome (XY).
manent cessation of life functions and the cessation of integrated Gametes are produced by meiosis (mı̄-ō′ sis) (see chapter 19).
tissue and organ function. The most widely accepted indication of Meiosis is called a reduction division because it produces gametes
death in humans is whole brain death, which is manifested clinically
by the absence of (1) response to stimulation, (2) natural respira- Figure 20.18  Human Karyotype Reproductive
tion and heart function, and (3) brainstem reflexes, in addition to
an electroencephalogram that remains isoelectric (“flat”) for at The 23 pairs of chromosomes in humans consist of 22 pairs of autosomal
least 30 minutes. chromosomes (numbered 1–22) and 1 pair of sex chromosomes. The autosomal
When determining death, certain conditions also need to be chromosome pairs are numbered in order from largest to smallest. This is
ruled out. For example, some central nervous system poisons can the karyotype of a male, as evidenced by the presence of an X and a Y sex
cause a flat electroencephalogram, but the patient can be revived chromosome. A female karyotype would have 2 X chromosomes.
if the effects of the poison are eliminated. Hypothermia slows
all chemical reactions, including those involved in degenerative
changes that begin at the time of death. As a result, a person suf-
fering from hypothermia can exhibit no response to stimulation,
exhibit no respiration or heartbeat, and have a flat electroencepha-
logram for more than 30 minutes and still be revived.
Neocortical (nē-ō-kōr′ ti-kăl) death is a condition in which
major portions of the cerebrum are no longer functioning. The
patient is comatose and incapable of responding to stimuli. However,
heartbeat and respiration still continue because of some relatively
unimpaired brainstem functions. Also, because some brainstem
function remains, the electroencephalogram is not flat but exhibits
some level of activity. Under these conditions, some state laws
require that the patient be kept alive by intravenous feeding and by
other support equipment. The patient may have previously stated in
a living will that, if neocortical death occurs and he or she cannot be
returned to a reasonably normal level of function, no artificial sup-
port should be applied in an attempt to keep the body alive.

580 Chapter 20

that have half the number of chromosomes that somatic cells cell. Both chromosomes of a given pair contain similar but not
have. When a sperm cell and a secondary oocyte fuse during necessarily identical genes. Similar genes on homologous chro-
­fertilization, each contributes one-half of the chromosomes nec- mosomes are called alleles (ă-lēlz′ ). If the two allelic genes are
essary to ­produce new somatic cells. Therefore, half of an indi- identical, the person is homozygous (hō-mō-zı̄′ gŭs) for the trait
vidual’s genetic makeup comes from the father, and half comes specified by that gene. If the two alleles are slightly different, the
from the mother. person is heterozygous (het′ er-ō-zı̄′ gŭs) for the trait. All the genes
During meiosis, the chromosomes are distributed in such a in one homologous set of 23 chromosomes in one individual con-
way that each gamete receives only one chromosome from each stitute that person’s genome (jē′ nōm).
homologous (hŏ-mol′ ō-gŭs) pair of chromosomes (see chapter 19). Through the processes of meiosis, gamete formation, and
Homologous chromosomes contain the same complement of fertilization, the distribution of genes received from each parent is
genetic information. The determination of sex illustrates, in part, essentially random. This random distribution is influenced by sev-
how chromosomes are distributed during gamete formation and eral factors, however. First, all the genes on a given chromosome
fertilization. During meiosis and gamete formation, the pair of sex are linked; that is, they tend to be inherited as a set rather than
chromosomes separates, so that each secondary oocyte receives as individual genes because chromosomes, not individual genes,
one X chromosome, whereas each sperm cell receives either segregate during meiosis. Second, homologous chromosomes may
an X chromosome or a Y chromosome (figure 20.19). When a exchange genetic information during meiosis by crossing over.
sperm cell fertilizes an oocyte to form a single cell, the sex of the Segregation errors may occur during meiosis. As the chro-
individual is determined randomly. If the oocyte is fertilized by a mosomes separate, the two members of a homologous pair may
sperm cell with a Y chromosome, a male results; if the oocyte is not segregate. As a result, one of the daughter cells receives both
fertilized by a sperm cell with an X chromosome, a female results. chromosomes of a given pair, and the other daughter cell receives
Estimating the probability that any given zygote will be male or none. When the gametes are fertilized, the resulting zygote has
female is much like flipping a coin. For any given fertilization either 47 chromosomes or 45 chromosomes, rather than the normal
event, there is a 50% probability that the individual will be female 46. When this condition results in an abnormal autosomal chromo-
and 50% probability that the individual will be male. some number, it is usually, but not always, lethal and is one reason
for a high rate of early embryo loss. Down syndrome, or trisomy 21,
Genes which results when there are three #21 chromosomes, is one of the
few autosomal trisomies that is not lethal. In contrast, sex chromo-
Each chromosome contains thousands of genes. Each gene con- some abnormalities are not usually lethal. For example, Turner
sists of a certain portion of a DNA molecule, but not necessarily Syndrome or monosomy X, in which only one X chromosome is
a continuous stretch of DNA. Genes determine the proteins in a present, results in sterility and abnormal sexual development but
does not affect the mental development of the female.
XX XY
Dominant and Recessive Genes
Meiosis Meiosis
Most human genetic traits are recognized because defective alleles
Sperm cells for those traits exist in the population. For example, on chromo-
some 11 is a gene that produces an enzyme necessary for the
X X Y Possible synthesis of melanin, the pigment responsible for skin, hair, and
Oocytes combinations eye color (see chapter 5). An abnormal allele, however, produces
XX XY a defective enzyme not capable of catalyzing one of the steps in
X melanin synthesis. If a given person inherits two defective alleles,
Female Male a homozygous condition, the person is unable to produce melanin
and therefore lacks normal pigment. This condition is referred to
XX XY as albinism (al′ bi-nizm).
For many genetic traits, the effects of one allele for that
Female Male trait can mask the effect of another allele for the same trait. For
example, a person who is heterozygous for the melanin-producing
50% 50% enzyme gene has one normal gene for melanin production and
female male one defective gene for melanin production. One copy of the gene
(XX) (XY) and its resulting enzymes are enough to make normal melanin. As
a result, the person who is heterozygous produces melanin and
Reproductive Figure 20.19  Inheritance of Sex appears normal. In this case, the allele that produces the normal
enzyme is said to be dominant, whereas the allele producing the
The female produces oocytes containing one X chromosome, whereas the abnormal enzyme is recessive. By convention, dominant traits are
male produces sperm cells with either an X or a Y chromosome. There are indicated by uppercase letters, and recessive traits are indicated by
four possible combinations of an oocyte with a sperm cell, half of which lowercase letters. In this example, the letter A designates the domi-
produce females and half of which produce males. nant normal, pigmented allele, the letter a the recessive abnormal
allele. Not all dominant traits are the normal condition, and not all
recessive traits are abnormal. Many examples exist of abnormal

Development, Heredity, and Aging 581

dominant traits. For example, Huntington disease, a degenerative Sex-Linked Traits
neurological disease, is caused by an abnormal dominant gene.
The possible combinations of dominant and recessive alleles Traits affected by genes on the sex chromosomes are called
for normal melanin production versus albinism are AA (homo- sex-linked traits. Most sex-linked traits are X-linked; that is,
zygous dominant, normal), Aa (heterozygous, normal), and aa they are on the X chromosome. Only a few Y-linked traits exist,
(homozygous recessive, albino). The combination of alleles a largely because the Y chromosome is very small. An example of
person has for a given trait is called the genotype (jen′ ō-tı̄p). The an X-linked trait is hemophilia A (classic hemophilia), in which
person’s appearance is called the phenotype (fē′ nō-tı̄p). A person the person is unable to produce one of the clotting factors (see
with the genotype AA or Aa has the phenotype of normal pigmen- chapter 11). Consequently, clotting is impaired, and persistent
tation, whereas a person with the genotype aa has the phenotype bleeding can occur, either spontaneously or as a result of an
of albinism. The recessive trait is expressed only when no allele injury. Hemophilia A is a recessive trait, and the allele for the trait
for the dominant trait is present. A carrier is a heterozygous is located on the X chromosome. The possible genotypes and phe-
person with an abnormal recessive gene but a normal phenotype notypes are therefore
because the normal dominant allele for that gene is also present.
XHXH (normal homozygous female)
Predict 6 XHXh (normal heterozygous female)
XhXh (hemophiliac homozygous female)
Polydactyly (pol-e¯-dak′ti-le¯) is the condition of having extra XHY (normal male)
fingers or toes. Given that polydactyly is a dominant trait, list XhY (hemophiliac male)
all the possible genotypes and phenotypes for polydactyly. Use
the letters D and d for the alleles. Note that a female must have both recessive alleles to exhibit
hemophilia, whereas a male has hemophilia if he has one reces-
The inheritance of dominant and recessive traits can be deter- sive allele, because he has only one X chromosome. A Punnett
mined if the genotypes of the parents are known. For example, if square representing the inheritance of hemophilia is illustrated in
an albino person (aa) mates with a heterozygous normal person figure 20.21. If a woman who is a carrier for hemophilia mates
(Aa), the probability that the child will be albino (aa) is one-half, with a man who does not have hemophilia, none of their daughters
and the probability that the child will be normal (Aa) is one-half. will have hemophilia; however, the probability that a son will
If two carriers (Aa) mate, the probability that the child will be have hemophilia is one-half. On the other hand, the probability
homozygous dominant (AA) or homozygous recessive (aa) is that a daughter will be a carrier is one-half.
one-fourth for either genotype. The probability that the child will be
heterozygous (Aa) is one-half. Such a probability can be determined
easily by using a table called a Punnett square (figure 20.20).

Mother (normal carrier) Father (normal)
XHXh XHY

Mother (normal carrier) Father (normal carrier)
Aa Aa

Meiosis Meiosis

Meiosis Meiosis Sperm cells
XH Y
Sperm cells
Aa XH XHXH XHY
Oocytes
A AA Aa Possible
Oocytes Normal Normal combinations
carrier
a Possible Xh XHXh XhY
combinations
Aa aa
Normal Albino Genotype and phenotype probabilities:
carrier
1 XHXH (normal female) : 1 XHX h (carrier female) :
4 4

Genotype and phenotype probabilities: 1 XHY (normal male) : 1 X hY (male with hemophilia)
4 4
1 AA (normal) : 1 Aa (normal carrier) : 1 aa (albino)
4 2 4

Figure 20.20  Inheritance of a Recessive Trait: Albinism Figure 20.21  Inheritance of an X-Linked Trait: Hemophilia Reproductive

A represents the normal pigmented condition, and a represents the XH represents the normal X chromosome condition with all clotting factors,
recessive unpigmented condition. This Punnett square represents a mating and Xh represents the X chromosome lacking an allele for one clotting
between two normal carriers. factor. This Punnett square represents a mating between a normal male
and a normal carrier female.

582 Chapter 20

Predict 7 aabbcc A A B B CC
(very light) (very dark)
Predict the probability of a girl with Turner Syndrome having
hemophilia if her mother is a carrier for hemophilia. (a) A a B b Cc A a B b Cc
30 (all offspring)
Other Types of Gene Expression
A a B b Cc
In some cases, the dominant allele does not completely mask the
effects of the recessive allele. This is called incomplete domi- Percentage of offspring 20
nance. An example of incomplete dominance is sickle-cell anemia,
in which the hemoglobin produced by the gene is abnormal. The 10
result is sickle-shaped red blood cells, which are likely to stick
in capillaries and tend to rupture more easily than normal red aabbcc A A B B CC
blood cells. The normal hemoglobin allele (S) is dominant over
the sickle-cell allele (s). A normal person (SS) has normal hemo- Aa b b cc AABBCc
globin, and a person with sickle-cell anemia (ss) has abnormal (two other combinations) (two other combinations)
hemoglobin. A person who is heterozygous (Ss) has half normal
hemoglobin and half abnormal hemoglobin and usually has only a AaBb cc AAB b Cc
few sickle-shaped red blood cells. This condition is called sickle- (five other combinations) (five other combinations)
cell trait.
In another type of gene expression, called codominance A a B b Cc
(kō-dom′ i-năns), two alleles can combine to produce an effect (b) (six other combinations)
without either of them being dominant or recessive. For example,
a person with type AB blood has A antigens and B antigens on the Figure 20.22  Inheritance of a Polygenic Trait: Skin Color
surface of his or her red blood cells (see chapter 11). The antigens
result from a gene that causes the production of the A antigen and This example shows three genes for skin color. Each of the dominant alleles
a different gene that causes the production of the B antigen, and (A, B, C) contributes one “unit of dark color” to the offspring (indicated
neither gene is dominant or recessive in relation to the other. by a dark dot). Each of the recessive alleles (a, b, c) contributes one “unit
Many traits, called polygenic (pol-ē-jen′ ik) traits, are deter- of light color” to the offspring (indicated by a light dot). The dominant
mined by the expression of multiple genes on different chromo- alleles are incompletely dominant over the recessive alleles. (a) In a
somes. Examples are height, intelligence, eye color, and skin mating between a very light-skinned person (aabbcc) and a very dark-
color. Polygenic traits typically have a great amount of variability. skinned person (AABBCC), all the offspring are of intermediate color.
For example, there are many shades of eye color and skin color (b) In a mating between two people of intermediate skin color (AaBbCc),
(figure 20.22). a very low percentage of the offspring (less than 2%) are either very light
or very dark, and most are of intermediate color.
Genetic Disorders
Reproductive The first step in genetic counseling is to attempt to deter-
Genetic disorders are caused by abnormalities in a person’s genetic mine the genotype of the individuals involved. A family tree, or
makeup—that is, in his or her DNA. They may involve a single pedigree, provides historical information about family members.
gene or an entire chromosome. Some genetic disorders result from Figure 20.23 shows the pedigree for a simple dominant trait, such
a mutation (mū-tā′ shŭn; to change), a change in a gene that usu- as Huntington disease, a neurological disorder. Sometimes,
ally involves a change in the nucleotides composing the DNA (see
chapter 2). Mutations occur by chance or can be caused by chemicals,
radiation, or viruses. If mutations occur in reproductive cells,
abnormal traits resulting from these mutations can be passed from
one generation to the next.
The importance of genes is dramatically illustrated by situa-
tions in which the alteration of a single gene results in a genetic
disorder. For example, in phenylketonuria (fen′ il-kē′ tō-nū′ rē-ă)
(PKU), the gene responsible for producing an enzyme that converts
the amino acid phenylalanine to the amino acid tyrosine is defective.
Therefore, phenylalanine accumulates in the blood and is eventually
converted to harmful substances that can cause mental retardation.

Genetic Counseling

Genetic counseling includes predicting the possible results of
matings involving carriers of harmful genes and talking to parents
or prospective parents about the possible outcomes and treatments
of a genetic disorder. With this knowledge, prospective parents can
make informed decisions about having children.

Development, Heredity, and Aging 583

CLINICAL IMPACT Human Genome Project

the human genome comprises A genomic (je˘-nom′ik, je-no¯m′ik) map Human Genome Project, a large-scale
all the genes in one homologous set of is a description of the DnA nucleotide project to characterize the entire human
human chromosomes. researchers estimate sequences of the genes and their locations genome, was completed in February 2003.
that humans have 20,000–25,000 genes. on the chromosomes (figure 20A). the

a

aa a a aa
b ab
b ba
a b b c a b
b 34 c d
c b c 7 b cb 11
d 2 5 6 8 9 10

1

a ab a a a
c b b
b 13 a a a c
12 b 16 b b
a bc a a a
14 15 20 21 b
17 18 19 22 d Y
X

Chromosome pairs

1. a. Gaucher disease 7. a. Diabetes* 13. a. Breast cancer* 20. a. Severe combined
b. Prostate cancer
b. Osteogenesis imperfecta b. Retinoblastoma immunodeficiency
c. Glaucoma
c. Cystic fibrosis c. Wilson disease 21. a. Amyotrophic lateral sclerosis*
d. Alzheimer disease*
d. Obesity* 14. a. Alzheimer disease* 22. a. DiGeorge syndrome
2. a. Familial colon cancer*
b. Waardenburg syndrome 8. a. Werner syndrome 15. a. Marfan syndrome b. Neurofibromatosis, type 2

3. a. Lung cancer b. Burkitt lymphoma b. Tay-Sachs disease X a. Duchenne muscular
b. Retinitis pigmentosa*
9. a. Malignant melanoma 16. a. Polycystic kidney disease dystrophy
4. a. Huntington disease
b. Parkinson disease b. Friedreich ataxia b. Crohn disease* b. Menkes syndrome

5. a. Cockayne syndrome c. Tuberous sclerosis 17. a. Tumor suppressor protein c. X-linked severe combined
b. Familial polyposis of the
10. a. Multiple endocrine neoplasia, b. Breast cancer* immunodeficiency
colon
type 2 c. Osteogenesis imperfecta d. Factor VIII deficiency
c. Asthma
b. Gyrate atrophy 18. a. Amyloidosis (hemophilia A)
6. a. Spinocerebellar ataxia
b. Diabetes* 11. a. Sickle-cell anemia b. Pancreatic cancer*

c. Epilepsy* b. Multiple endocrine neoplasia 19. a. Familial hypercholesterolemia

12. a. Zellweger syndrome b. Myotonic dystrophy

b. Phenylketonuria (PKU)

*Gene responsible for only some cases.

Figure 20A

representative genetic defects mapped to date. the bars and lines indicate the locations of the genes listed for each chromosome.

knowing the phenotypes of relatives makes it possible to determine amount of a given substance, such as an enzyme, produced by a Reproductive
a person’s genotype. As part of the process of collecting informa- carrier can be tested. For example, carriers for cystic fibrosis pro-
tion, a karyotype can be prepared. For some genetic disorders, the duce more salt in their sweat than is normal.

584 Chapter 20

Figure 20.23  Pedigree of a Simple Dominant Trait

Males are indicated by squares, females by circles.
People who express the trait are indicated in purple.
The horizontal line between symbols represents a mating.
The symbols connected to the mating line by vertical and
horizontal lines represent the children resulting from the
mating in order of birth from left to right. Matings not
related to the pedigree are not shown.

DISEASES AND DISORDERS:  Pregnancy

CONDITION DESCRIPTION

Ectopic pregnancy Pregnancy that occurs outside the uterus, usually in the uterine tube; as the pregnancy progresses, the tube
ruptures, which may lead to life-threatening internal bleeding
Miscarriage
Placenta previa Death or early delivery of the fetus; approximately 15% of all pregnancies end in miscarriage

Toxemia (tok-s¯e′m¯e-a˘) The placenta implants near the opening of the uterus in the cervical canal; as the fetus grows and the uterus
(pregnancy-induced hypertension) stretches, the placenta may tear away from the uterine wall, resulting in death of the fetus; associated
Teratogens (ter′a˘-to¯-jenz) hemorrhaging can be life-threatening to the mother as well.

Fetal alcohol syndrome (FAS) Increased blood pressure associated with pregnancy; may result in convulsions, kidney failure, and death of both
the mother and fetus
Infections
Rubella (German measles) Drugs or other chemicals that can cross the placenta and cause birth defects in the developing embryo; for
example, thalidomide (tha-lid′o-m¯ı d) causes abnormal limb development
Neonatal gonorrheal ophthalmia
Brain dysfunction, growth retardation, and facial peculiarities in children of women who consumed substantial
Chlamydial conjunctivitis amounts of alcohol while pregnant
Human immunodeficiency virus
(HIV) If rubella is contracted by a pregnant female, the fetus may be severely affected; results include visual and
hearing defects as well as mental retardation.

Severe form of conjunctivitis contracted by an infant passing through the birth canal of a mother infected with
gonorrhea; carries a high risk of blindness; can be prevented by treating a newborn’s eye with silver nitrate
and antibiotics

Contracted by an infant passing through the birth canal of a mother infected with chlamydia

Virus that causes acquired immunodeficiency syndrome (AIDS); can infect the fetus in utero, during parturition, or
during breastfeeding; the drug azidothymidine (AZT) inhibits HIV replication and can reduce the number of infants
who contract AIDS if given to HIV-infected pregnant women and to their newborn infants

Reproductive ANSWER TO Learn to Predict stimulates the release of prolactin and oxytocin, which stimulate
continued milk production and milk letdown. If Ming stops breast-
In this chapter we learned that the production of breast milk de- feeding for a prolonged period of time, prolactin secretion will
pends on a number of hormones. Estrogen and progesterone cause stop, which will cause milk production to decline. Ming can retain
expansion of the duct system and the secretory units of the breast. the capacity to breastfeed her baby by using a breast pump while
Estrogen and progesterone levels during pregnancy prevent the she takes the prescribed medication. After finishing the antibiotic,
breast from producing milk, but after parturition, these hormone Ming can then continue to breastfeed her baby.
levels drop dramatically. Prolactin produced by the anterior pitu-
itary stimulates milk production. We also learned that suckling Answers to the rest of this chapter’s Predict questions are in Appendix E.

Development, Heredity, and Aging 585

Summary 2. Increased estrogen, decreased progesterone, and secretions from the Reproductive
fetal adrenal cortex initiate parturition.
20.1 Prenatal Development   (p. 560)
3. Stretching of the uterus stimulates oxytocin secretion, which
1. Prenatal development is an important part of an individual’s life. stimulates uterine contractions.
About 3 of every 100 people are born with a birth defect requiring
early medical attention. 20.3 The Newborn   (p. 573)

2. The developing human is called an embryo during the first 8 weeks Respiratory and Circulatory Changes
of the prenatal period and a fetus from 8 weeks until birth. 1. Inflation of the lungs at birth results in closure of the foramen ovale

3. Developmental age is 14 days less than clinical age. and the ductus arteriosus.
2. When the umbilical cord is cut, blood no longer flows through the
Fertilization
Fertilization, the union of the secondary oocyte and sperm cell, results in umbilical vessels.
a zygote.
Digestive Changes
Early Cell Division The digestive system only gradually develops the ability to digest a
The zygote undergoes divisions until it becomes a mass of cells. variety of foods.

Blastocyst 20.4 Lactation   (p. 574)
1. The embryonic mass develops a cavity and is known as the blastocyst.
2. The blastocyst consists of a trophoblast and an inner cell mass, 1. Estrogen and progesterone help stimulate the growth of the breasts
during pregnancy.
where the embryo forms.
2. Suckling stimulates prolactin and oxytocin synthesis. Prolactin
Implantation of the Blastocyst and Development stimulates milk production, and oxytocin stimulates milk letdown.
of the Placenta
1. The blastocyst implants in the uterus about 7 days after fertilization. 20.5 First Year Following Birth   (p. 576)
2. The embryonic portion of the placenta is derived from the
Many of the important changes that occur during the first year after birth
trophoblast of the blastocyst. are linked to continued development of the brain.

Maternal Hormonal Changes 20.6 Life Stages   (p. 577)
1. Human chorionic gonadotropin levels are high in early pregnancy
The eight stages of life are germinal period (fertilization to 14 days);
but then decline to low levels. embryo (14–56 days after fertilization); fetus (56 days after fertilization to
2. Progesterone and estrogen levels are low in early pregnancy but birth); neonate (birth–1 month); infant (1 month–1 or 2 years); child (1 or
2 years–puberty); adolescent (puberty–20 years); adult (20 years–death).
increase to high levels late in pregnancy.
The Aging Process
Formation of the Germ Layers 1. Aging occurs as irreplaceable cells wear out and the tissue becomes
1. The embryo forms around the primitive streak, which forms about
more brittle and less able to repair damage.
14 days after fertilization. 2. Atherosclerosis is the deposit of lipids in the arteries. Arteriosclerosis
2. All tissues of the body are derived from the three primary germ
is hardening of the arteries.
layers: ectoderm, mesoderm, and endoderm.
Death
Neural Tube and Neural Crest Formation Death is defined as the absence of brain response to stimulation, the absence
The nervous system develops from a neural tube that forms in the of natural respiration and heart function, and a flat electroencephalogram
ectodermal surface of the embryo and from neural crest cells derived for 30 minutes.
from the developing neural tube.
20.7 Genetics   (p. 579)
Formation of the General Body Structure
1. The limbs develop as outgrowths called limb buds. Chromosomes
2. The face develops by fusion of five tissue masses. 1. Humans have 46 chromosomes in 23 pairs.
2. Males have the sex chromosomes XY, and females have XX.
Development of the Organ Systems 3. During gamete formation, the chromosomes of each pair of
1. The digestive tract develops as the developing embryo closes off
chromosomes separate; therefore, half of a person’s genetic makeup
part of the yolk sac. comes from the father and half from the mother.
2. The heart develops as two blood vessels fuse into a single tube that
Genes
develops septa to form four chambers. 1. A gene is a portion of a DNA molecule. Genes determine the
3. The kidneys and the reproductive system are closely related in their
proteins in a cell.
development. 2. Genes are paired (located on the paired chromosomes).
3. Dominant genes mask the effects of recessive genes.
Growth of the Fetus 4. Sex-linked traits result from genes on the sex chromosomes.
During the fetal period, the fetus increases 15-fold in length and 5. In incomplete dominance, the heterozygote expresses a trait that is
1400-fold in weight.
intermediate between the two homozygous traits.
20.2 Parturition   (p. 572) 6. In codominance, neither gene is dominant or recessive, but both are

1. Uterine contractions force the baby out of the uterus during labor. fully expressed.

586 Chapter 20

7. Polygenic traits result from the expression of multiple genes. Genetic Counseling

Genetic Disorders 1. A pedigree (family history) can be used to determine the risk of
1. A mutation is a change in the DNA. having children with a genetic disorder.
2. Some genetic disorders result from an abnormal distribution of
2. Specific chemical tests or an examination of a person’s karyotype
chromosomes during gamete formation. can be used to determine a person’s genotype.

Review and Comprehension

1. Define clinical age and developmental age, and state the difference 15. How does the loss of cells that are not replaced affect the aging
between the two in number of days. Define embryo and fetus. process? Give examples.

2. What are the events during the first week after fertilization? Define 1 6. How does the loss of tissue elasticity affect the aging process?
zygote, morula, and blastocyst. Give examples.

3. How does the placenta develop? 17. How does aging affect the immune system?
4. Describe the formation of the germ layers and the role of the 1 8. Define death.
1 9. Give the number and type of chromosomes in the karyotype of a
primitive streak.
5. How are the neural tube and neural crest cells formed? What do human somatic cell. How do the chromosomes of a male and a
female differ from each other?
they become? 2 0. How do the chromosomes in somatic cells and gametes differ from
6. Describe the formation of the limbs and face. each other?
7. Describe the formation of the digestive tract. 2 1. What is a gene, and how are genes responsible for the structure and
8. How does the single heart tube become four-chambered? function of cells?
9. What major events distinguish embryonic and fetal development? 22. Define homozygous dominant, heterozygous, and homozygous
10. Describe the hormonal changes that take place before and during recessive.
2 3. What is a sex-linked trait? Give an example.
parturition. 2 4. How do sickle-cell anemia, type AB blood, and a person’s height
11. What changes take place in the newborn’s circulatory system and result from the expression of genes?
25. What is a mutation?
digestive system shortly after birth? 2 6. What is the cause of the genetic disorder Down syndrome?
12. What hormones are involved in preparing the breasts for lactation? 2 7. How are pedigrees, karyotypes, and chemical tests used in genetic
counseling?
What hormones are involved in milk production and milk letdown?
13. Describe the changes in motor and language skills that take place

during the first year of life.
1 4. List the different life stages.

Critical Thinking 4. Dimpled cheeks are inherited as a dominant trait. Is it possible for
two parents, each of whom has dimpled cheeks, to have a child
1. A physician tells a woman that her pregnancy has progressed 44 days without dimpled cheeks? Explain.
since her last menstrual period (LMP). How many days has the embryo
been developing, and what developmental events are occurring? 5. The ability to roll the tongue to form a “tube” results from a
dominant gene. Suppose that a woman and her son can both roll
2. A high fever can prevent neural tube closure. If a woman has a high their tongues, but her husband cannot. Is it possible to determine
fever about 35 to 45 days post-LMP, what kinds of birth defects if the husband is the father of her son based on this trait?
may be seen in the developing embryo?
6. A woman who does not have hemophilia marries a man who has
3. A drug that stops the production of milk in the breast after a few the disorder. Determine the genotypes of both parents if they have
days probably has which effect? a daughter with hemophilia.
a. inhibits prolactin secretion
b. inhibits oxytocin secretion Answers in Appendix D
c. increases estrogen secretion
d. increases progesterone secretion
e. increases prolactin secretion

Reproductive

Appendix A

Table of Measurements

TABLE A.1 Table of Measurements

Unit Metric Equivalent Symbol U.S. Equivalent

Measures of Length km 0.62137 mile
m 39.37 inches
1 kilometer = 1000 meters dm 3.937 inches
1 meter = 10 decimeters or 100 centimeters cm 0.3937 inch
1 decimeter = 10 centimeters mm
1 centimeter = 10 millimeters µm No U.S. equivalent
1 millimeter = 1000 micrometers nm
1 micrometera = 1/1000 millimeter or 1000 nanometers Å 1.308 cubic yards
1 nanometera = 10 angstroms or 1000 picometers pm 0.03531 cubic foot
1 angstrom = 1/10,000,000 millimeter 0.06102 cubic inch
1 picometer = 1/1,000,000,000 millimeter m3
dm3 264.18 gallons
Measures of Volume cm3 (cc) 1.0567 quarts
0.4227 cup
1 cubic meter = 1000 cubic decimeters kL 0.3381 ounce
1 cubic decimeter = 1000 cubic centimeters L
1 cubic centimeter = 1000 cubic millimeters or 1 milliliter dL 2.2046 pounds
mL 0.0353 ounce
Measures of Capacity 0.1543 grain
µL
1 kiloliter = 1000 liters
1 liter = 10 deciliters kg
1 deciliter = 100 milliliters g
1 milliliter = volume of 1 gram of water at standard cg
mg
1 microliter temperature and pressure
= 1 mm3 (cubic millimeter) or 10–6 L

Measures of Mass

1 kilogram = 1000 grams
1 gram = 100 centigrams or 1000 milligrams
1 centigram = 10 milligrams
1 milligram = 1/1000 gram

aA micrometer was formerly called a micron (µm), and a nanometer was formerly called a millimicron (mµ).

TABLE A.2 Comparative Temperature Scales

100°C 37°C 0°C –40°F = –40°C

110 100 90 80 70 60 50 40 30 20 10 0 –10 –20 –30 –40
°C

°F
230 220 210 200 190 180 170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0 –10 –20 –30 –40

212°F 98.6°F 32°F
Water boils Body temperature Water freezes

A-1

Appendix B

Some Reference Laboratory Values

tAble b.1 blood, Plasma, or Serum Values

test Normal Values Clinical Significance

Acetoacetate plus acetone 0.32–2 mg/100 mL Values increase in diabetic acidosis, fasting, high-fat diet, and toxemia
of pregnancy.
Ammonia 9–33 μmol/L
Amylase (micromol/L) Values decrease with proteinuria and as a result of severe burns; values
increase in multiple myeloma.
4–25 U/mLa
Values increase in acute pancreatitis, intestinal obstruction, and mumps;
Barbiturate 0 values decrease in cirrhosis of the liver, toxemia of pregnancy, and
Bilirubin chronic pancreatitis.
Blood volume 0.4 mg/100 mL
Calcium Coma level: phenobarbital, approximately 10 mg/100 mL; most other
Carbon dioxide content 8.5–9% of body weight drugs, 1–3 mg/100 mL.
in kilograms
Carbon monoxide Values increase in conditions causing red blood cell destruction, biliary
Chloride 8.5–10.5 mg/100 mL obstruction, or liver inflammation.

24–30 mEq/Lb Values increase in hyperparathyroidism, vitamin D hypervitaminosis; values
20–26 mEq/L in infants decrease in hypoparathyroidism, malnutrition, and severe diarrhea.

(as HCO3−) Values increase in respiratory diseases, vomiting, and intestinal obstruction;
0 values decrease in acidosis, nephritis, and diarrhea.
100–106 mEq/L
Symptoms with over 20% saturation
Creatine phosphokinase Female: 5–35 mU/mL
(CPK) Male: 5–55 mU/mL Values increase in Cushing syndrome, nephritis, and hyperventilation;
values decrease in diabetic acidosis, Addison disease, and diarrhea,
Creatinine 0.6–1.5 mg/100 mL and also after severe burns.

Ethanol 0 Values increase in myocardial infarction and skeletal muscle diseases,
such as muscular dystrophy.
Glucose Fasting 70–110 mg/100 mL
Values increase in certain kidney diseases.
Iron 50–150 μg/100 mL
0.3–0.4%, marked intoxication
Lactic acid 0.6–1.8 mEq/L 0.4–0.5%, alcoholic stupor
Over 0.5%, alcoholic coma
Lactic dehydrogenase 60–120 U/mL
Values increase in diabetes mellitus, liver diseases, nephritis,
hyperthyroidism, and pregnancy; values decrease in hyperinsulinism,
hypothyroidism, and Addison disease.

Values increase in various anemias and liver disease; values decrease in
iron-deficiency anemia.

Values increase with muscular activity and in congestive heart failure,
severe hemorrhage, shock, and anaerobic exercise.

Values increase in pernicious anemia, myocardial infarction, liver diseases,
acute leukemia, and widespread carcinoma.

cA unit (U) is the quantity of a substance that has a physiological effect.
bA milliequivalent (mEq) is defined in Appendix C.

A-2

Appendix B A-3

table B.1 Blood, Plasma, or Serum Values (continued)

Test Normal Values Clinical Significance

Lipids Cholesterol 120–220 mg/100 mL; Increased values for cholesterol and triglycerides are connected
cholesterol esters 60–75% of with increased risk of cardiovascular disease, such as heart attack
Lithium cholesterol; phospholipids and stroke.
Osmolality 9–16 mg/100 mL as lipid
Oxygen saturation (arterial) phosphorus; total fatty acids Values decrease in acidosis, nephritis, and diarrhea; values increase in
(see Po2) 190–420 mg/100 mL respiratory diseases, intestinal obstruction, and vomiting.
Pco2 Total lipids Values decrease as a result of hypoventilation, severe diarrhea,
pH 450–1000 mg/100 mL Addison disease, and diabetic acidosis; values increase due to
Triglycerides hyperventilation, Cushing syndrome, and vomiting.
40–150 mg/100 mL Values increase in polycythemia and decrease in anemia and obstructive
pulmonary diseases.
Toxic levels 2 mEq/L Values increase in cancer of the prostate gland, hyperparathyroidism,
some liver diseases, myocardial infarction, and pulmonary embolism.
285–295 mOsm/kg water Values increase in hyperparathyroidism, some liver diseases, and
pregnancy.
96–100% Values increase in hypoparathyroidism, acromegaly, vitamin D
hypervitaminosis, and kidney diseases; values decrease in
35–43 mm Hg hyperparathyroidism.

7.35–7.45 Total protein values increase in severe dehydration and shock; values
decrease in severe malnutrition and hemorrhage.
Po2 75–100 mm Hg
Phosphatase (acid) (breathing room air) 20–25 mg/100 mL
Phosphatase (alkaline) Over 30 mg/100 mL
Phosphorus (inorganic) Male: total 0.13–0.63 U/mL Over 20 mg/100 mL after age 60
Female: total 0.01–0.56 U/mL Values increase in nephritis and severe dehydration; values decrease in
Potassium Addison disease, myxedema, kidney disease, and diarrhea.
Protein 13–39 IU/Lc (infants and
adolescents up to 104 IU/L) 5–15 mg/100 mL
Salicylate Values increase in response to increased dietary protein intake; values
Therapeutic 3–4.5 mg/100 mL decrease in impaired renal function.
Toxic (infants in first year up to Values increase in gout and toxemia of pregnancy and as a result of
6 mg/100 mL) tissue damage.

3.5–5 mEq/100 mL

Total 6–8.4 g/100 mL
Albumin 3.5–5 g/100 mL
Globulin 2.3–3.5 g/100 mL

0

Sodium 135–145 mEq/L

Sulfonamide 0
Therapeutic 8–25 mg/100 mL
Urea nitrogen

Uric acid 3–7 mg/100 mL

cA unit (U) is the quantity of a substance that has a physiological effect.

A-4 Appendix B

table B.2 Blood Count Values

Test Normal Values Clinical Significance

Clotting (coagulation) time 5–10 min Values increase in afibrinogenemia and hyperheparinemia, severe liver
damage.
Fetal hemoglobin Newborns: 60–90%
Before age 2: 0–4% Values increase in thalassemia, sickle-cell anemia, and leakage of fetal
Hemoglobin Adults: 0–2% blood into maternal bloodstream during pregnancy.

Hematocrit Male: 14–16.5 g/100 mL Values decrease in anemia, hyperthyroidism, cirrhosis of the liver, and
Ketone bodies Female: 12–15 g/100 mL severe hemorrhage; values increase in polycythemia, congestive
Platelet count Newborn: 14–20 g/100 mL heart failure, and obstructive pulmonary disease and at high altitude.

Male: 40–54% Values increase in polycythemia, severe dehydration, and shock; values
Female: 38–47% decrease in anemia, leukemia, cirrhosis, and hyperthyroidism.

0.3–2 mg/100 mL Values increase in ketoacidosis, fever, anorexia, fasting, starvation, and
Toxic level: 20 mg/100 mL a high-fat diet.

250,000–400,000/μL Values decrease in anemias and allergic conditions and during cancer
chemotherapy; values increase in cancer, trauma, heart disease,
Prothrombin time 11–15 s and cirrhosis.
Red blood cell count
Males: 4.6–6.2 million/μL Values increase in prothrombin and vitamin deficiency, liver disease, and
Reticulocyte count Females: 4.2–5.4 million/μL hypervitaminosis A.

1–3% Values decrease in systemic lupus erythematosus, anemias, and Addison
disease; values increase in polycythemia and dehydration and
White blood cell Neutrophils 60–70% following hemorrhage.
count, differential Eosinophils 2–4%
Basophils 0.5–1% Values decrease in iron-deficiency and pernicious anemias and radiation
White blood cell Lymphocytes 20–25% therapy; values increase in hemolytic anemia, leukemia, and
count, total Monocytes 3–8% metastatic carcinoma.

5000–9000/μL Neutrophils increase in acute infections; eosinophils and basophils
increase in allergic reactions; monocytes increase in chronic infections;
lymphocytes increase during antigen-antibody reactions.

Values decrease in diabetes mellitus, anemias and following cancer
chemotherapy; values increase in acute infections, trauma, some
malignant diseases, and some cardiovascular diseases.

Appendix B A-5

table B.3 Urine Values Clinical Significance

Test Normal Values Values increase in diabetic acidosis and during fasting.

Acetone and 0 Values increase in glomerular nephritis and hypertension.
acetoacetate Values increase in diabetes mellitus and liver disease.
Albumin 0 to trace Values increase in urinary tract infection.
Ammonia 20–70 mEq/L Values increase in biliary tract obstruction.
Bacterial count Under 10,000/mL Values increase in hyperparathyroidism and decrease in
Bile and bilirubin 0 hypoparathyroidism.
Calcium Under 250 mg/24 h Values decrease in pyloric obstruction and diarrhea; values increase in
Addison disease and dehydration.
Chloride 110–254 mEq/24 h Values decrease in diarrhea, malabsorption syndrome, and adrenal cortical
insufficiency; values increase in chronic renal failure, dehydration, and
Potassium 25–100 mEq/L Cushing syndrome.
Values decrease in diarrhea, acute renal failure, and Cushing syndrome;
Sodium 75–200 mg/24 h values increase in dehydration, starvation, and diabetic acidosis.
Values increase in renal diseases.
Creatinine clearance 100–140 mL/min Values increase in infections and decrease in muscular atrophy, anemia,
Creatinine 1–2 g/24 h and certain kidney diseases.
Values increase in diabetes mellitus and certain pituitary gland disorders.
Glucose 0 Values increase in certain kidney diseases.
Urea clearance Over 40 mL of blood
cleared of urea per min Values decrease in complete biliary obstruction and severe diarrhea;
Urea 25–35 g/24 h values increase in liver diseases and hemolytic anemia.
Values increase in gout and decrease in certain kidney diseases.
Uric acid 0.6–1 g/24 h
Casts Values increase in nephrosis and heavy metal poisoning.
Epithelial Occasional Values increase in nephritis and pyelonephritis.
Granular Occasional Values increase in glomerular membrane damage and fever.
Hyaline Occasional Values increase in pyelonephritis; blood cells appear in urine in response
Red blood cell Occasional to kidney stones and cystitis.
Values increase in kidney infections.
White blood cell Occasional Color varies with hydration, diet, and disease states.
Color Amber, straw,
transparent yellow Odor becomes acetone-like in diabetic ketosis.
Odor Aromatic Values decrease in aldosteronism and diabetes insipidus; values increase
Osmolality 500–800 mOsm/kg water in high-protein diets, heart failure, and dehydration.
Values decrease in acidosis, emphysema, starvation, and dehydration;
pH 4.6–8 values increase in urinary tract infections and severe alkalosis.

A-6 Appendix B

table B.4 Hormone Levels Normal Values

Test Excretion: 5–19 μg/24 ha
Supine: 48 ± 29 pg/mLb
Steroid hormones Upright: 65 ± 23 pg/mL
Aldosterone Supine: 175 ± 75 pg/mL
Fasting, at rest, 210 mEq sodium diet Upright: 532 ± 228 pg/mL

Fasting, at rest, 10 mEq sodium diet 8 am: 5–25 μg/100 mL
8 pm: Below 10 μg/100 mL
Cortisol Adult male: 300–1100 ng/100 mLc
Fasting Adolescent male: over 100 ng/100 mL
At rest Female: 25–90 ng/100 mL
Testosterone
15–170 pg/mL
Peptide hormones Undetectable in normal individuals
Adrenocorticotropin (ACTH)
Calcitonin Below 5 ng/mL
Growth hormone (GH) Children: over 10 ng/mL
Fasting, at rest Male: below 5 ng/mL
After exercise Female: up to 30 ng/mL

Insulin 6–26 μU/mL
Fasting Below 20 μU/mL
During hypoglycemia Up to 150 μU/mL
After glucose Male: 6–18 mU/mL
Luteinizing hormone (LH) Preovulatory or postovulatory female: 5–22 mU/mL
Midcycle peak 30–250 mU/mL
Parathyroid hormone Less than 10 μEq/Ld
Prolactin 2–15 ng/mL
Renin activity
Normal diet 1.1 ± 0.8 ng/mL/h
Supine 1.9 ± 1.7 ng/mL/h
Upright
Low-sodium diet 2.7 ± 1.8 ng/mL/h
Supine 6.6 ± 2.5 ng/mL/h
Upright 0.5–3.5 μU/mL
Thyroid-stimulating hormone (TSH) 15.25 μg T4/100 mL
Thyroxine-binding globulin 4–12 μg/100 mL
Total thyroxine

a1 microgram (1 μg) is equal to 10−6 g.
b1 picogram (1 pg) is equal to 10−12 g.
c1 nanogram (1 ng) is equal to 10−9 g.
dμEq microequivalent, 1/1000 mEq, which is defined in Appendix C.

Appendix C

Solution Concentrations

Physiologists often express solution concentra- Molality The osmolality of a solution is a reflection
tion in terms of percent, molarity, molality, and of the number, not the type, of particles in a
equivalents. Although 1-M solutions have the same number solution. Thus, a 1-osm solution contains 1 osm
of solute particles, they do not have the same of particles per kilogram of solvent, but the par-
Percent number of solvent (water) molecules. Because ticles may be all one type or a complex mixture
58.5 g of sodium chloride occupies less volume of different types.
The weight-volume method of expressing per- than 180 g of glucose, the sodium chloride solu-
cent concentrations states the weight of a solute tion has more water molecules. Molality is a The concentration of particles in body flu-
in a given volume of solvent. For example, to method of calculating concentrations that takes ids is so low that the measurement milliosmole
prepare a 10% solution of sodium chloride, 10 g into account the number of solute and solvent (mOsm), 1/1000 of an osmole, is used. Most
of sodium chloride is dissolved in a small molecules. A 1-molal solution (1-m) is 1 mol body fluids have an osmotic concentration of
amount of water (solvent) to form a salt solu- of a substance dissolved in 1 kg of water. Thus, approximately 300 mOsm and consist of many
tion. Then additional water is added to the salt a 1-m solution of sodium chloride and a 1-m different ions and molecules. The osmotic con-
solution to form 100 mL of salt solution. Note solution of glucose contain the same number of centration of body fluids is important because it
that the sodium chloride was dissolved in water sodium chloride and glucose compounds dis- influences the movement of water into or out of
and then diluted to the required volume. The solved in the same amount of water. cells (see chapter 3).
sodium chloride was not dissolved directly in
100 mL of water. When sodium chloride (NaCl) is dissolved Equivalents
in water, it dissociates, or separates, to form
Molarity two ions: a Na+ and a Cl−. Glucose, however, Equivalents are a measure of the concentra-
does not dissociate when dissolved in water. tions of ionized substances. One equivalent (Eq)
Molarity determines the number of moles of Although 1-m solutions of sodium chloride and is 1 mol of an ionized substance multiplied by
solute dissolved in a given volume of solvent. A of glucose have the same number of sodium the absolute value of its charge. For example,
mole (abbreviated mol) of a substance contains chloride and glucose compounds, because of 1 mol of NaCl dissociates into 1 mol of Na+
6.023 × 1023 number (Avogadro number) of dissociation the sodium chloride solution con- and 1 mol of Cl−. Thus, there are 1 Eq of Na+
particles, such as atoms, ions, compounds, or tains twice as many particles as the glucose (1 mol × 1) and 1 Eq of Cl− (1 mol × 1). One
molecules. A 1-molar (1-M) solution is made by solution (one Na+ and one Cl− for each glucose mole of CaCl2 dissociates into 1 mol of Ca2+
dissolving 1 mol of a substance in enough water molecule). To report the concentration of these and 2 mol of Cl−. Thus, there are 2 Eq of Ca2+
to make 1 L of solution. For example, 1 mol of substances in a way that reflects the number of (1 mol × 2) and 2 Eq of Cl− (2 mol × 1). In
sodium chloride solution is made by dissolving particles in a given mass of solvent, the concept an electrically neutral solution, the equivalent
58.44 g of sodium chloride in enough water to of osmolality is used. The osmolality of a solu- concentration of positively charged ions is equal
make 1 L of solution. One mole of glucose solu- tion is the molality of the solution times the to the equivalent concentration of the negatively
tion is made by dissolving 180.2 g of glucose number of particles into which the solute disso- charged ions. One milliequivalent (mEq) is
in enough water to make 1 L of solution. Both ciates in 1 kg of solvent. Thus, 1 mol of sodium 1/1000 of an equivalent.
solutions have the same number (Avogadro chloride in 1 kg of water is a 2-osmolal (2-osm)
number) of sodium chloride or glucose com- solution because sodium chloride dissociates to
pounds in solution. form two ions.

A-7

Appendix D

Answers to Critical Thinking Questions

Chapter 1 8. After passing through the left thoracic 6. There was most likely at least one
wall, the first membrane to be encountered enzyme present that was required for one
1. D is correct. Positive-feedback is the parietal pleura. Continuing of the initial reactions. Boiling denatured
mechanisms result in movement through the pleural cavity, the visceral any enzymes present in the solution.
away from homeostasis and are usually peritoneum and the left lung are pierced. Without enzymes, the reaction(s) will
harmful. The continually decreasing Leaving the lung, the bullet penetrates not occur.
blood pressure is an example. Negative- the visceral pleura, the pleural cavity,
feedback mechanisms result in a return and the parietal pleura (remember that Chapter 3
to homeostasis. The elevated heart rate the lung is surrounded by a double
is a negative-feedback mechanism that membrane sac). Next the parietal 1. B is the most logical conclusion. Swollen
attempts to return blood pressure to a pericardium, the pericardial cavity, lung tissue suggests that the tissues had
normal value. In this case, the negative- the visceral pericardium, and the heart been submerged in a hypotonic solution,
feedback mechanism was inadequate are encountered. such as fresh water. Because the bay
to restore homeostasis, and blood contains salt water, which is slightly
pressure continued to decrease. Medical 9. The kidneys are located in the abdominal hypertonic to blood, it is unlikely he
intervention (a transfusion) increased cavity but are retroperitoneal. When a drowned in the bay. It is more likely he
blood volume and blood pressure. With the person is lying prone, it is possible to cut drowned in fresh water and was later
increase in blood pressure, the positive- through the posterior abdominal wall and placed in the bay. Although this is the
feedback mechanism is interrupted and the remove a kidney without cutting through most logical conclusion of those given,
negative-feedback mechanism is able to parietal peritoneum. there are possibilities other than murder.
maintain blood pressure. For example, he may have accidentally
Chapter 2 drowned in a freshwater stream and then
2. Student B is correct. As the muscles been washed into the bay.
become more active, they use more O2. 1. Because atoms are electrically neutral,
The increased rate of respiration the iodine atom has the same number 2. B is correct. A solution that is isotonic
maintains blood and muscle tissue O2 of protons and electrons. The gain of an causes cells to neither shrink nor swell.
levels (homeostasis) and is a negative- electron means the iodine ion has one Therefore, there is no net movement of
feedback mechanism. more electron than protons and therefore water between the blood and the dialysis
a charge of minus one. The correct fluid. Also, if the solution has the same
3. a. Inferior symbol is I−I. composition as blood except for having
b. Posterior (dorsal) or deep no urea, only urea diffuses from a higher
c. Distal or inferior 2. a. Dissociation concentration in the blood to the lower
d. Lateral b. Synthesis concentration in the dialysis fluid.
c. Decomposition A solution that is isotonic and contains
4. The heel is distal, inferior, and posterior only protein will cause many different
to the kneecap. The kneecap is proximal, 3. Muscle contains proteins and, to small molecules (not just urea) that are
superior, and anterior to the heel. increase muscle mass, proteins must be found in blood to diffuse into the dialysis
synthesized. The synthesis of molecules fluid. Distilled water is hypotonic and
5. The wedding band should be worn in living organisms results from chemical causes blood cells to swell and undergo
proximal to the engagement ring. reactions that require the input of energy. lysis. Also, molecules that are able to
The energy needed to drive these synthesis pass through the dialysis membrane
6. The pancreas is located in the right-upper reactions comes from chemical reactions diffuse from the blood into the distilled
and left-upper quadrants; it is located that release energy. The energy-releasing water. Blood is not a good solution to use
in the epigastric and left hypochondriac reactions occur during the decomposition because it would have to be blood that has
regions. The top of the urinary bladder is of food molecules. already had urea removed in order to be
located in the right-lower quadrant and useful as dialysis fluid.
the left-lower quadrant; it is located in the 4. The sodium bicarbonate dissociates to
hypogastric region. The rest of the urinary form sodium ions (Na−) and bicarbonate 3. Because the plasma membrane stays
bladder is located in the pelvic cavity. ions (HCO3−). Because this is a reversible the same size, even though small pieces
reaction, the HCO3− added to the solution of membrane from secretory vesicles
7. The pelvic cavity contains the uterus, bind with H+ to form CO2 and water. The are continually added to the plasma
which increases greatly in size during decrease in H+ causes the pH to increase membrane, one must conclude that some
pregnancy as the fetus within the uterus (become more basic). process is removing small pieces of
grows. However, the pelvic cavity is membrane at the same rate that they are
surrounded by bones, which are not 5. The slight amount of heat functioned as added. The cell membrane is constantly
expandable. Therefore, the uterus activation energy and started a chemical being recycled.
moves superiorly into the abdominal reaction. The reaction released energy,
cavity, crowding abdominal organs and especially heat, which caused the solution
dramatically increasing the size of the to become very hot.
abdominal cavity.

A-8

Appendix D A-9

4. The main function of this cell is to columnar ciliated epithelium replaces the vessels and increased blood vessel
secrete proteins. Well-developed rough stratified squamous epithelium and debris permeability. Blocking these effects
endoplasmic reticulum for protein removal resumes. could reduce the body’s ability to deal
production, well-developed Golgi 2. Tight junctions prevent the passage of with harmful agents, such as bacteria.
apparatuses for the packaging of proteins materials between the epithelial cells. On the other hand, antihistamines also
for secretion, and many vesicles for 3. A secretory epithelium is generally reduce many of the unpleasant symptoms
exocytosis are typical of many cells that a simple epithelium. To manufacture of inflammation, making the patient
secrete proteins. Many mitochondria large amounts of enzymes, a cuboidal more comfortable, and this can be
produce large amounts of ATP. The ATP or columnar cell with the appropriate considered beneficial. Antihistamines
serves as an energy source for forming the organelles, such as rough endoplasmic are commonly taken to prevent allergy
bonds between the amino acids, for the reticulum and Golgi apparatuses, would symptoms that are often an overreaction
active transport of amino acids into the be expected. The pancreas is formed of the inflammatory response to foreign
cell, and for exocytosis of the completed of simple columnar epithelium. The substances, such as pollen.
proteins. Many microvilli, which greatly epithelium has microvilli on its free 8. Collagen synthesis is required for
increase surface area for transport, can surface, which increase the surface area granulation tissue and scar formation.
also be found in cells that produce and and facilitate secretion. The tight junctions If collagen synthesis does not occur
secrete proteins. However, large numbers that connect the epithelial cells of the because of a lack of vitamin C, or if
of mitochondria or large amounts of pancreatic glands and duct system to each collagen synthesis is slowed, wound
microvilli can be found in other types other prevent damage to the underlying healing does not occur or is slower than
of cells as well. tissues (by the action of pancreatic normal. One might expect that the density
digestive enzymes). of collagen fibers in a scar is reduced and
5. The sickle-cell gene for producing the 4. a. The stratified squamous epithelium that the scar is not as durable as a normal scar.
protein has a different nucleotide than the
normal gene for producing the protein. lines the mouth provides protection. Chapter 5
Because the nucleotides are the set of Replacement of it with simple columnar
instructions for making the protein, the epithelium makes the lining of the 1. Yes, the skin (dermis) can be overstretched
change means the instructions contain mouth much more susceptible to as a result of obesity.
an error. When mRNA copies the damage because the single layer of
instructions from the faulty DNA, the epithelial cells is easier to damage. 2. Carotene, a yellow pigment from ingested
error is also copied. Consequently, when b. Tendons attach muscles to bone. When plants, accumulates in lipids. The stratum
the amino acids are joined together to muscles contract, muscles pull on the corneum of a callus has more layers of
form the protein at the ribosome, the tendons and, because the tendons are cells than other noncalloused parts of
instructions are wrong and the protein is attached to bone, the bones move. If the skin and the cells in each layer are
incorrectly assembled. A substitution of the tendons contained elastic tissue, surrounded by lipids. The carotene in the
a single nucleotide results in a different the tendons would be more like elastic lipids make the callus appear yellow.
amino acid in the chain of amino acids bands. The muscles would contract
that make up the protein. This change and stretch the tendons. Not all of the 3. The vermillion border is covered by
alters the shape of the protein. Just as the force of muscle contraction would be keratinized epithelium that is a transition
function of enzymes depends on their transferred to the bones to cause them between the nonkeratinized stratified
shape, the functions of other proteins to move. epithelium of the mucous membrane and
depend on their shapes. The incorrectly c. If bones were made of elastic cartilage, the keratinized stratified epithelium of
manufactured proteins in the red blood they would be much more flexible and the facial skin. The mucous membrane
cells have the wrong shape and do could bend and then return to their has mucous glands, which secrete mucus
not stack correctly. As a result of the original shape. They would not be rigid (see chapter 4). The mucus helps keep the
abnormal stacking, the red blood cells structures, like bone, that support our inner surface of the lips moist. In addition,
have an abnormal, sickle shape. weight and result in efficient movement. the inner surface of the lips is “sealed off”
5. The fibers are organized along the direction most of the time and is moistened by saliva.
Chapter 4 of pull on the ligaments—that is, parallel In contrast to facial skin, the skin of the
to the length of the ligament. When the vermillion border does not have sebaceous
1. Pseudostratified columnar ciliated back is bent, the ligaments are stretched. or sweat glands. Without sebaceous glands,
epithelium is found in the trachea. It The elastic recoil of the stretched ligaments the surface of the vermillion border is not
produces mucus that traps dust and debris helps straighten the back. protected against drying by sebum. Also,
in air. The cilia move the mucus with 6. When blood is ejected into the aorta, the the vermillion border is not as heavily
entrapped dust and debris to the throat, aortic wall expands and the diameter of keratinized as facial skin; that is, the
where it is swallowed. In heavy smokers, the aorta increases. The elastic fibers are number of cell layers with surrounding
the pseudostratified columnar epithelium arranged in a circular fashion, so that, when lipids is less. Consequently, the vermillion
is replaced by stratified squamous the aortic wall expands, the elastic fibers border dries out more easily.
epithelium, which serves a protective are stretched. Recoil of the fibers causes the
function against the irritating materials aorta to resume its original shape, which 4. The hair follicle, but not the hair, is
in the smoke. Unfortunately, this type of helps force blood to flow through the aorta. surrounded with nerve endings that can
epithelium is not ciliated, so removal of 7. Chemical mediators of inflammation detect movement or pulling of the hair.
foreign materials from the trachea is normally produce beneficial responses, The hair is dead, keratinized epithelium,
more difficult. After 2 years without such as dilation of small-diameter blood so cutting the hair is not painful.
smoking, the original pseudostratified
5. Several methods have some degree of
success in treating acne: (1) Kill the
bacteria. One effective agent is benzoyl

A-10 Appendix D

peroxide in some acne medications. the humerus and the ulna, but not as up by forcefully flexing the wrist and
Antibiotics have also been used to treat tightly to the humerus as does the ulna. fingers. The anterior thigh is best built
severe cases of acne. (2) Prevent sebum Pulling forcefully on the forearm would, by extending the knee, as in partial knee
production. Isotretinoin, or Accutane therefore, be more likely to pull the radius bends. The posterior leg muscles are best
(a derivative of vitamin A), has proven away from the humerus than the ulna. built by forcefully plantar flexing the ankle
effective in preventing sebum production. 4. Because the female pelvis is relatively and toes, as in standing on one’s toes. The
However, Accutane produces birth wider than the male pelvis, the heads abdominal muscles are best built by flexing
defects and should be used with caution. of the femora (pl. of femur) are placed the vertebral column against resistance, as
Estrogen, a female sex hormone, has also wider apart. For the lower limbs to in leg lifts or partial sit-ups. Of course, each
been used to treat severe cases of acne. be placed directly below the center of exercise has to be repeated many times to
(3) Unplug the follicle. Some sulfur gravity in the body, the femora must be increase the size of the muscles.
compounds speed up peeling of the angled in more sharply in females than 5. This is a typical hamstring injury (pulled
skin and unplug the follicle. in males. This angle may bring the knees hamstring), in which one or more of the
6. Rickets is a disease of children resulting closer together, resulting in the condition hamstring muscles are either pulled away
from inadequate vitamin D. With called knock-kneed. from their attachment to bone or torn. The
inadequate vitamin D, there is insufficient 5. All skeletons, including those of humans, slight flexion of the knee and the bulge in
absorption of calcium from the intestine, have features unique to each species. A the muscle occur because muscle fibers
resulting in soft bones. If adequate human skeleton can be identified based on contract in the hamstrings, but the tear
vitamin D is ingested, rickets is prevented, its unique anatomical features. In addition, does not allow antagonist muscles in the
whether one is dark- or fair-skinned. female skeletons have several anatomical anterior thigh to pull on the muscle fibers
However, if dietary vitamin D is inadequate, features that distinguish them from male to lengthen them. The pain results from
when the skin is exposed to ultraviolet light, skeletons. For example, the female pelvis the damaged tissue in the muscle (flexion
it can produce a precursor molecule that can differs in several features from the male and pain are also due to spasmodic
be converted to vitamin D. Dark-skinned pelvis (see figure 6.32). contractions of the muscle in response to
children are more susceptible to rickets the injury). Because of the tissue damage
because the additional melanin in their Chapter 7 and cramps, the muscles could not
skin screens out the ultraviolet light and respond to voluntary nervous control and
they produce less vitamin D. 1. Botulism toxin decreases acetylcholine could not contract.
7. When first exposed to the cold temperature release in the neuromuscular junction. This 6. a. First, we are told that Javier suffered
just before starting the run, the blood prevents action potentials in skeletal muscle
vessels in the skin constrict to conserve cells. Thus, the respiratory muscles (e.g., interruptions in functions under control
heat. This produces a pale skin color. the diaphragm) relax and do not contract. of the muscular system (blurred vision,
Dilation of skin blood vessels does not Other explanations that you could have nausea, and spastic contractions). The
occur at this time because the skin has not proposed because they would also lead to fact that his muscles contracted without
been exposed to the cold long enough to respiratory failure are that the toxin prevents relaxing tells us that the poison has
cause skin temperature to fall below 15°C acetylcholine from binding to its receptor interferred with the body’s ability to
(27°F). After running awhile, as a result of on skeletal muscle cells and that the toxin turn off the stimulation of the muscle
the excess heat generated by the exercise, inhibits the production of acetylcholine. cell. Organophosphate poisons inhibit
the blood vessels in the skin dilate. This the activity of acetylcholinesterase.
results in heat loss and helps prevent 2. Harvey’s hands became fatigued as a result Acetylcholinesterase breaks down
overheating. Increased blood flow through of ATP depletion. Without ATP, the muscles acetylcholine at the neuromuscular
the skin causes it to turn red. After the run, moving the fingers could not contract and, junction and limits the length of
the body still has excess heat to eliminate, so, the fingers could not flex or extend. In time the acetylcholine stimulates the
so for awhile the skin remains red. addition, his inability to release his grip is postsynaptic terminal of the muscle
an indication of physiological contracture, fiber. Under organophosphate poison
Chapter 6 in which too little ATP is present to allow influence, acetylcholine accumulates
cross-bridge release. in the synaptic cleft and continuously
1. The injury separated the head (epiphysis) stimulates the muscle fiber. As a result,
from the shaft (diaphysis) at the 3. Both the 100-m dash and weight lifting the muscle remains contracted until
epiphyseal plate, which is cartilage. (to a lesser extent) involve short bursts it fatigues. Death is caused by the
Because the epiphyseal plate is the site of of anaerobic activity, so in both cases the victim’s inability to breathe. Either
bone elongation, damage to the epiphyseal researcher should expect to find more fast- the respiratory muscles are in spastic
plate can interfere with bone elongation, twitch muscle in the gastrocnemius of these paralysis or they are so depleted of
resulting in a shortened limb. athletes. The 10,000-m run involves aerobic ATP that they cannot contract at all.
metabolism, and the outstanding athlete b. First, we learned from the Clinical
2. If Justin landed on his heels, he could have should have more slow-twitch fibers. Impact “Acetylcholine Antagonists”
broken one or both of his heel bones, the that certain chemicals can affect the
calcaneus. When Hefty Stomper stepped on 4. The exercise that best builds the anterior metabolism of neurotransmitters such
Justin’s foot, the most likely bones broken arm muscles is flexion of the elbow as acetylcholine. Medical practitioners
would be the metatarsal bones, which make against force, such as in pull-ups. A sometimes use such chemicals to help
up the main structure of the foot. pull-up with the hand supinated builds counteract exposure to poisons. For
both the biceps and the brachialis, but example, we learned that the chemical
3. The humerus articulating with the ulna a curl with the hand pronated builds curare binds to acetylcholine receptors
and radius forms the elbow joint. The the brachialis to a greater extent. The and thus prevents acetylcholine from
ulna fits tightly over the end of the posterior arm is best built by extension
humerus. The radius attaches to both of the elbow, as in push-ups or dips. The
anterior forearm muscles are best built

Appendix D A-11

binding to them. Because curare most affected, and convex glasses would increase more rapidly than aldosterone
blocks the acetylcholine receptors, do the best job of replacing the lenses for levels in response to a decrease in
muscles do not respond as normal near vision, such as when reading. blood volume. ADH is secreted within
to nervous stimulation. In the case 2. The fovea centralis, where a person minutes by the posterior pituitary gland
of organophosphate poisoning, this focuses on an object, contains almost in response to dehydration of the body.
is actually desirable, because the entirely cones. Cones do not detect faint The hypothalamus detects a decrease
body has too much acetylcholine at light, so dim stars, which can be detected in blood volume and an increase in
the neuromuscular junction, since by the rods, are lost from vision when the the concentration of the blood, which
acetylcholinesterase is inhibited. Thus, person looks directly at them. When the stimulates neurons in the hypothalamus to
by blocking the acetylcholine receptors person looks slightly to the side, the more secrete ADH. ADH binds to membrane-
with curare, we can prevent spastic peripherally located rods can again detect bound receptors in the kidney. The cells of
paralysis of the respiratory muscles. the faint light from the stars. the kidney respond within minutes. As a
3. Under normal conditions, pressure changes result, the kidney produces a small volume
Chapter 8 in the middle ear occur through the auditory of very concentrated urine. Aldosterone
tube. The auditory tube connects the middle is secreted in response to decreased blood
1. If one series of neurons had more neurons, ear to the pharynx, which opens to the pressure (caused by decreased blood
it would have more synapses, which should outside of the body through the oral and volume), but the process involves other
slow down the rate of action potential nasal cavities. This allows air pressure compounds. The kidneys respond to a
propagation. Also, if one series were to equalize on both sides of the eardrum. decrease in blood pressure by secreting
unmyelinated and the other myelinated, When a person is under water, the increased renin. Renin acts as an enzyme to break
the unmyelinated series would be slower. water pressure on the outside of the eardrum down angiotensinogen into angiotensin I.
forces the eardrum toward the middle Angiotensin-converting enzyme converts
2. The phrenic nerves are the nerves to ear because the external water pressure angiotensin I to angiotensin II. Finally,
the diaphragm. The left phrenic nerve exceeds the air pressure in the middle ear. angiotensin II stimulates the adrenal
would be cut to paralyze the left side of As a result, the eardrum cannot vibrate as cortex to increase aldosterone secretion.
the diaphragm. freely as when the pressure is equalized, Aldosterone binds to intracellular
and sound transmission is dampened. If receptors in cells of the kidney. The
3. a. Radial nerve. This nerve supplies the pressure difference becomes too great, response of these cells is to increase
posterior (extensor) muscles. When it can rupture the eardrum. specific mRNA and protein synthesis.
these muscles are paralyzed, the flexor 4. Sound is normally transmitted through the The new mRNA and protein synthesis
muscles are unopposed and result in middle ear by vibration of the auditory requires a significant amount of time.
the flexed limb described. ossicles. A vibrating tuning fork touching The response to the synthesis of new
the mastoid process sets up vibrations in proteins is to increase the rate of solute
b. Femoral nerve the temporal bone, causing the perilymph reabsorption in the kidney, including
4. The cerebellum controls motor functions, and endolymph of the inner ear to Na+. This enhances water reabsorption
vibrate. These vibrations cause the basilar by the kidney.
such as balance, muscle tone, and fine membrane to vibrate and are therefore 3. Vitamin D increases the rate of
motor movements. Cerebellar dysfunction is perceived as sound. transport of Ca2+ across the wall of the
characterized as a loss of balance, a loss of 5. When a contaminated hand rubs the eyes, intestine. Therefore, in response to high
motor tone, and an inability to control fine the virus can be introduced into tears on concentrations of vitamin D, blood Ca2+
motor movements, such as touching one’s the conjunctiva. From there the virus can levels can become abnormally high.
nose with the eyes closed. Such patients spread into the lacrimal canaliculi and Because the blood Ca2+ levels are elevated,
appear to be drunk (alcohol apparently pass through the nasolacrimal duct into the rate of PTH secretion decreases to low
most directly affects the cerebellum). the nasal cavity. levels. Also, the elevated blood Ca2+ levels
5. The blow to the head erased Louis’s short- stimulate calcitonin secretion.
term memory, which would have extended Chapter 10 4. If the adrenal cortex degenerated,
to about 10 minutes before the blow, and glucocorticoids, mineralocorticoids,
that information was never transferred to 1. The hormone binds to a membrane- and the androgens normally secreted
long-term memory. bound receptor and activates a G protein by the adrenal cortex would no longer
6. a. Hypoglossal nerve (cranial nerve XII) mechanism. Because a drug inhibits the be secreted. A lack of glucocorticoid
b. Optic nerve (cranial nerve II) binding of GTP to a protein, GTP cannot hormone secretion results in a reduced
c. Trigeminal nerve (cranial nerve V) bind to the α subunit of the G protein ability to maintain blood nutrient levels,
d. Facial nerve (cranial nerve VII) complex. Also, the fact that a drug that such as glucose, between meals or during
e. Oculomotor nerve (cranial nerve III) inhibits the breakdown of cyclic-AMP periods when no food is available. The
7. Nervous system stimulation of the causes an increased response suggests ability to inhibit inflammation is also lost.
digestive system occurs primarily through that the α subunit of the G protein Reduced levels of mineralocorticoids
the vagus nerve (cranial nerve X), which complex, with GTP bound to it, activates result in the loss of Na+ in the urine
arises from the brain. Therefore, an injury the enzymes that are responsible for the and the loss of water in the urine. Thus,
to the spinal cord at the level of C6 does synthesis of cyclic-AMP. the ability to regulate blood pressure is
not affect the functioning of this nerve. reduced. Reduced secretion of androgens
2. The effect of ADH on cells is mediated also occurs. Because the testes secrete
Chapter 9 through membrane-bound receptors, androgens, the reduced androgen secretion
whereas the effect of aldosterone on in males is not significant. The effect of
1. The lenses of the eye are biconvex cells is mediated through intracellular
structures and are most important in close receptors. In addition, ADH levels
vision as they are thickened (made more
convex) by relaxation of the suspensory
ligaments (accommodation). Therefore, if
they were removed, close vision would be

A-12 Appendix D

reduced androgens in females is unclear, (polycythemia). In addition, if the is a more likely instrument for detecting
although adrenal androgens may influence process is not done properly, there is a heart murmur. A condition that causes a
sexual behavior, to some degree, in females. a risk of infection. heart murmur could also cause an obvious
5. Aldosterone increases Na+ reabsorption 2. Symptoms resulting from decreased abnormality in the ECG, but that is not
from the distal nephron and it increases red blood cells are associated with a always the case.
K+ secretion into the nephron. Elevated decreased ability of the blood to carry O2: 2. Starling’s law of the heart is an intrinsic
aldosterone secretion results in the shortness of breath, weakness, fatigue, regulatory mechanism, whereas
increased retention of Na+ and H2O in and pallor. Symptoms resulting from parasympathetic innervation of the heart is
the kidney and an increased rate of K+ decreased platelets are associated with a a component of the extrinsic regulation of
elimination in the urine. As a result, decreased ability to form platelet plugs the heart. Cutting the vagus nerve does not
blood pressure increases and blood and clots: small areas of hemorrhage in significantly affect the ability of Starling’s
K+ levels can get very low. the skin, bruises, and decreased ability to law of the heart to operate.
6. After 24 hours without food, blood stop bleeding. A symptom resulting from 3. Cutting sensory nerve fibers from
glucose levels will be decreasing. This decreased white blood cells is an increased baroreceptors would reduce the
will activate mechanisms that cause blood susceptibility to infections and diseases. frequency of action potentials delivered
glucose levels to increase. The decreasing 3. The hypoventilation results in decreased to the medulla oblongata from the
blood glucose levels will result in an blood O2, which stimulates the baroreceptors. This results because the
increased rate of secretion of cortisol, a release of erythropoietin from the normal blood pressure stimulates the
glucocorticoid, from the adrenal cortex, kidneys. The erythropoietin stimulates baroreceptors. An increase in blood
epinephrine from the adrenal medulla, red blood cell production in the red bone pressure increases the action potential
and glucagon from pancreatic islets. marrow. Consequently, red blood cell frequency, and a decrease in blood
The decreasing blood glucose levels numbers increase. pressure decreases the action potential
result in increased ACTH secretion from 4. Removal of the stomach results in removal frequency. Because cutting the sensory
the anterior pituitary gland; increased of intrinsic factor, which is necessary for nerve fibers decreases the action potential
sympathetic nervous system stimulation of adequate vitamin B12 absorption in the frequency, this acts as a signal to the
the adrenal medulla, resulting in increased small intestine. Therefore, the patient medulla oblongata that a decrease in
epinephrine secretion; and increased would develop pernicious anemia. blood pressure has occurred, even though
secretion of glucagon from the pancreatic Vitamin B12 injections can be used to the blood pressure has not decreased.
islets. Cortisol increases lipid and protein prevent pernicious anemia. The medulla oblongata responds by
breakdown, so that these substances can 5. Vitamin B12 and folate are necessary for increasing sympathetic action potentials
be used as energy sources. It also causes blood cell division. Lack of these vitamins and reducing parasympathetic action
increased glucose synthesis, primarily results in anemia. Iron is necessary for potentials delivered to the heart.
from amino acids. Epinephrine and the production of hemoglobin. Lack of Consequently, the heart rate increases.
glucagon both bind to receptors on the iron results in iron-deficiency anemia. 4. When the internal carotid arteries are
liver and increase the release of glucose Vitamin K is necessary for the production clamped, blood flow and blood pressure
from the liver. The decreasing blood of many blood-clotting factors. Lack of in the clamped internal carotid arteries
glucose levels inhibit insulin secretion. vitamin K can greatly increase blood- decrease dramatically. Thus, blood
The decreased insulin secretion slows clotting time. pressure in the area of the baroreceptors
the uptake of glucose by tissues. Thus, 6. The anemia results from too little in the internal carotid arteries is low.
blood glucose levels are maintained hemoglobin. Because there is less Sensory neurons carry a lower frequency
within normal levels. hemoglobin, less hemoglobin is broken of action potentials from the baroreceptors
7. Stressful conditions cause increased down into bilirubin. Consequently, less of the internal carotid arteries to the
ACTH secretion. Increased ACTH bilirubin is excreted as part of the bile medulla oblongata. The cardioregulatory
stimulates the secretion of glucocorticoids, into the small intestine. With decreased center within the medulla oblongata
such as cortisol. One of the effects of bilirubin in the small intestine, bacteria responds as if the blood pressure has
increased cortisol secretion is inhibition produce fewer of the pigments that decreased by causing an increase in
of the immune response. This could lead normally color the feces. sympathetic stimulation and a decrease in
to an increased likelihood of a variety 7. Reddie Popper has hemolytic anemia. parasympathetic stimulation of the heart. In
of infections, including colds and other The RBC is lower than normal because the addition, epinephrine and norepinephrine
diseases. Stomach pains may be due red blood cells are being destroyed faster are released from the adrenal medulla.
to inflammation of the stomach. Many than they are replaced. With fewer red Consequently, there is an increased heart
stomach ulcers result from inflammation blood cells, hemoglobin and hematocrit rate and stroke volume. Therefore, blood
caused by bacteria. are lower than normal. Bilirubin levels are pressure in the aorta increases.
above normal because of the breakdown 5. A drug that blocks Ca2+ channels
Chapter 11 of the hemoglobin released from the decreases the heart rate and the force
ruptured red blood cells. of contraction of the heart. This
1. Blood doping increases the number of occurs because Ca2+ is involved in the
red blood cells in the blood, increasing Chapter 12 depolarization of the cardiac muscle
its oxygen-carrying capacity. However, cells. If less Ca2+ flows into the cardiac
the increased number of red blood cells 1. A heart murmur is an abnormal heart muscle cells, the rate and degree of
also makes it more difficult for the sound. It is unlikely that an ECG will depolarization decrease. The result is that
blood to flow through the blood vessels, reveal that he has a heart murmur because action potentials develop more slowly
increasing the workload on the heart. an ECG monitors the electrical activity of and depolarization does not occur to the
The same effect is seen in erythrocytosis the heart, not heart sounds. A stethoscope

Appendix D A-13

normal degree. Slower development of of ventricular diastole until just after the vein, the left subclavian vein, the left
action potentials slows the heart rate. The beginning of ventricular systole. During brachiocephalic vein, the superior vena
degree of depolarization causes less Ca2+ ventricular diastole, blood flows from the cava, and the right atrium of the heart
to enter the cell; consequently, the force of left atrium into the left ventricle. If the d. The right great saphenous vein, the
contraction decreases. aortic semilunar valve is leaky, blood will right femoral vein, the right external
6. Consuming a large amount of fluid also flow through the aortic semilunar iliac vein, the right common iliac vein,
increases the total volume of the blood, at valve into the left ventricle. Consequently, the inferior vena cava, and the right
least until the mechanisms that regulate the volume of the left ventricle and the atrium of the heart
blood volume decrease the blood volume pressure in the left ventricle become greater e. The renal vein, the inferior vena cava,
to normal values. Increased blood volume than normal during ventricular diastole. and the right atrium of the heart
causes an increase in venous return to the Because blood is leaking from the aorta, f. The superior mesenteric vein, the
heart. Because of Starling’s law of the the aortic pressure, during ventricular hepatic portal vein, the liver, the
heart, the increased venous return results diastole, is lower than normal in the aorta. hepatic veins, the inferior vena cava,
in an increased stroke volume. A slight Because of Starling’s law of the heart and right atrium of the heart
increase in the heart rate also occurs. during ventricular systole, the ventricular 3. The femoral artery and vein are close to
Mechanisms that regulate blood pressure, muscle contracts with a greater force and the surface in the femoral triangle, which
such as the baroreceptor reflex, would forces a greater volume of blood into is in the superior and medial part of the
prevent a large increase in blood pressure. the aorta. Consequently, the pressure in thigh. The femoral artery is the vessel
Therefore, there may be an increased the left ventricle is greater than normal into which the catheter will be placed.
stroke volume but the blood pressure during ventricular systole. Also, pressure The femoral vein cannot be used because
would not increase dramatically. in the aorta is greater than normal during extending a catheter superiorly in the
7. Cardiac output is influenced by the heart ventricular systole. femoral vein will deliver the catheter to
rate and stroke volume (CO = SV × HR). the right side of the heart. The anterior
An athlete’s cardiac output can be equal Chapter 13 interventricular artery is a branch of the
to a nonathlete’s cardiac output while they left coronary artery, which originates
are both at rest, even though the athlete’s 1. a. For the right side of the brain: the from the ascending aorta, just superior to
heart rate is lower than the nonathlete’s aorta, the brachiocephalic artery, the the aortic semilunar valve. The catheter
heart rate, because the stroke volume of right common carotid artery, the right is inserted into the femoral artery. From
the athlete’s heart is greater than the stroke internal carotid artery, the cerebral there, it passes through the external iliac
volume of the nonathlete’s heart. Athletic arterial circle, and then the brain tissue. artery, through the common iliac artery,
training causes a gradual hypertrophy For the left side of the brain: the aorta, and through the aorta. It passes through
(enlargement) of the heart. Therefore, the left common carotid artery, the the abdominal aorta, the thoracic aorta,
an athlete can maintain a cardiac output left internal carotid artery, the cerebral and the aortic arch to the beginning of
that is equal to a nonathlete’s because the arterial circle, and then the brain tissue the left coronary artery and then to the
athlete has an increased stroke volume anterior interventricular artery.
but a decreased heart rate. During b. For the left external portion of the skull: 4. Cells from the tumor can spread from
exercise, an athlete’s heart rate and stroke the aorta, the brachiocephalic artery, the the colon to the liver through the hepatic
volume increase. The stroke volume of right common carotid artery, the right portal vein. Cells from the tumor can enter
the athlete’s heart is much greater than external carotid artery, and then the the superior mesenteric or the inferior
the stroke volume of the nonathlete’s. external portion of the skull. For the left mesenteric vein. The cells can pass from
Therefore, the cardiac output of the side of the external portion of the skull: the superior mesenteric vein to the hepatic
athlete’s heart is greater than the cardiac the aorta, the left common carotid artery, portal vein. The cells can also pass from the
output of the nonathlete’s during exercise. the left external carotid artery, and then inferior mesenteric vein to the splenic vein
8. The walls of the ventricles are thicker than the external portion of the skull and then the hepatic portal vein. The cells
the walls of the atria because the force can pass through the hepatic portal vein to
that the ventricles must produce is greater c. The aorta, the left subclavian artery, the liver.
than the force the atria must produce. the left axillary artery, the left brachial 5. Reduced blood flow to the kidney
The pressure in the ventricles during artery, either the left radial or the ulnar stimulates renin secretion. Renin acts on
ventricular systole is substantially higher artery, and the left hand angiotensinogen to produce angiotensin I.
than the pressure in the atria during atrial Angiotensin I is converted to angiotensin II
systole. In addition, most of the ventricular d. The aorta, the right common iliac by the action of angiotensin-converting
filling (approximately 70%) occurs before artery, the external iliac artery, the enzyme. Angiotensin II causes
contraction of the atria. Contraction of the femoral artery, the popliteal artery, the vasoconstriction, which increases blood
atria is responsible for only about 30% of anterior tibial artery, and the anterior pressure. In addition, angiotensin II
ventricular filling. In contrast, all of the portion of the right leg stimulates the secretion of aldosterone
blood ejected from the ventricles during from the adrenal cortex. Aldosterone acts
ventricular systole is ejected because of 2. a. The left internal jugular vein, the left on the kidney, causing the reabsorption of
contraction of the ventricles. brachiocephalic vein, the superior vena Na+ and water, thus increasing the blood
9. An incompetent aortic semilunar valve is cava, and the right atrium of the heart volume. The increased blood volume
leaky. Thus, when it is closed, blood is able results in increased blood pressure.
to leak through it back into the left ventricle b. The right external jugular vein, 6. During exercise, vasoconstriction occurs
from the aorta. The aortic semilunar valve the right subclavian vein, the right in the viscera, but vasodilation occurs in
is normally closed from the beginning brachiocephalic vein, the superior vena the exercising muscles. Even though the
cava, and the right atrium of the heart

c. The superficial veins of the left hand
and forearm; either the left cephalic or
the left basilic vein; the left cephalic
vein and the left basilic vein empty
into the axillary vein; the left axillary

A-14 Appendix D

cardiac output is increased because of cells. Because active immunity can last to develop the reaction indicates a
the increase in stroke volume and heart longer than passive immunity, it is the delayed hypersensitivity reaction and,
rate, the blood pressure does not go up preferred method in most cases. However, therefore, cytokines.
as much as it would if vasoconstriction passive immunity is preferred in situations
occurred in the viscera without vasodilation in which immediate protection is needed, Chapter 15
of the blood vessels in the exercising because it takes time for active immunity
skeletal muscles. to develop. 1. Pressing firmly on the base of the scapulae
7. Dilation of arteries and veins allows 5. If the patient has already been vaccinated, decreases the volume of the thoracic cavity,
blood to accumulate in the dilated blood the booster shot stimulates a memory pleural pressure increases, and alveolar
vessels. Consequently, less blood is (secondary) response and rapid production pressure increases to a value greater than
returned to the heart (decreased venous of antibodies against the toxin. If the atmospheric pressure. Thus, air flows from
return). Because the venous return patient has never been vaccinated, the lungs. When the arms are lifted, gravity
is reduced, the stroke volume of the vaccinating him is not effective because causes the thoracic cavity to sag downward
heart decreases (see Starling’s law of there is not enough time for the patient and expand. The volume of the thoracic
the heart—chapter 12). Consequently, to develop his own primary response. cavity increases, pleural pressure decreases,
the heart does less work and less O2 is Therefore, an antiserum is given to and alveolar pressure decreases to less than
required to support the contraction of the provide immediate, but temporary, atmospheric pressure, causing air to flow
heart. Therefore, angina pains, which are protection. Sometimes both are given: into the lungs.
caused by inadequate O2 delivery to the The antiserum provides short-term
heart muscle, are reduced. protection and the tetanus vaccine 2. a. The victim’s lungs expand because the
stimulates the patient’s immune system rescuer is blowing air into the lungs
Chapter 14 to provide long-term protection. If the at a pressure higher than alveolar
shots are given at the same location in the pressure. When alveolar pressure
1. Elevation of the limb allows gravity to body, the antiserum (antibodies against the exceeds pleural pressure, the lungs
assist the movement of lymph toward the tetanus toxin) could cancel the effects of tend to expand.
heart. Massage moves lymph through the the tetanus vaccine (tetanus toxin altered
lymphatic vessels in the same fashion as to be nonharmful). b. Air flows out of the lungs because of
does contraction of skeletal muscle. The 6. Resistance to extracellular bacterial the natural recoil of the lungs. Elastic
application of pressure periodically to infections is accomplished by antibody- fibers in the lungs and surface tension
lymphatic vessels forces lymph to flow mediated immunity, which is not of water in the alveoli cause the recoil
toward the trunk of the body, but valves functioning properly here. Maternal of the lungs.
prevent the flow of lymph in the reverse antibodies (IGg) that crossed the placenta
direction. The removal of lymph from the provided protection following birth but 3. The best prediction would be that her
tissue helps relieve edema. eventually were degraded. Resistance vital capacity would be greatest when she
to intracellular viral infections is is standing up. In the upright position,
2. Normally, T cells are processed in accomplished by cell-mediated immunity, gravity tends to pull the abdominal organs
the thymus and then migrate to other which appears to be working normally. downward. As a result, movement of the
lymphatic tissues. Without the thymus, 7. At the first location, an antibody-mediated diaphragm is not as restricted and thoracic
this processing is prevented. Because response results in an inflammatory volume is increased. Lying down allows
there are normally five T cells for every B response (immediate hypersensitivity). abdominal organs to exert pressure on the
cell, the number of lymphocytes is greatly The combination of antibodies with the diaphragm, decreasing the thoracic volume.
reduced. The loss of T cells results in an allergen triggers the release and activation
increased susceptibility to infection and an of inflammatory chemicals. At the second 4. At sea level, all the gases in the atmosphere
inability to reject grafts because of the loss location, a cell-mediated response also exert a pressure of 760 mm Hg. If water
of cell-mediated immunity. In addition, results in an inflammatory response vapor is 10% of that gas mixture, then
because T cells are involved with the (delayed hypersensitivity). This probably water vapor must have a partial pressure
activation of B cells, antibody-mediated involves the release of lymphokines and of 760 × 0.10, or 76 mm Hg.
immunity is also depressed. the lysis of cells. At the other locations,
there is neither an antibody-mediated nor 5. As fluid accumulates in the alveoli, the
3. Injection B results in the greatest amount a cell-mediated response. layer through which O2 and CO2 must
of antibody production. At first, the 8. The ointment was a good idea for the diffuse in the alveoli becomes thicker. As
antigen causes a primary response. A few poison ivy, which caused a delayed the layer thickens, the rate at which gases
weeks later, the slowly released antigen hypersensitivity reaction—that is, too diffuse slows. Consequently, the amount
causes a secondary response, resulting in a much inflammation. For the scrape, it is of O2 that diffuses into the pulmonary
greatly increased production of antibodies. a bad idea because a normal amount of capillaries is reduced and the amount of
Injection A does not cause a secondary inflammation is beneficial and helps fight CO2 that diffuses out of the pulmonary
response because all of the antigen is infection in the scrape. capillaries decreases. The decreased
eliminated by the primary response. 9. Because both antibodies and cytokines blood O2 levels and the increased CO2
produce inflammation, the fact that levels stimulate the respiratory center
4. Active immunity varies from a few the metal in the jewelry resulted in and cause the rate and depth of respiration
weeks (e.g., the common cold) to lifelong inflammation is not enough information to increase. Oxygen therapy increases
(e.g., measles). Immunity can be long- to answer the question. However, the fact the Po2 in the alveoli and reduces the
lasting if enough memory cells (B or T) that it took most of the day (many hours) Pco2 in the alveoli. Therefore, O2 diffuses
are produced and persist to respond to more rapidly from the alveoli into the
later antigen exposure. Passive immunity pulmonary capillaries and CO2 diffuses
is not long-lasting because the individual more rapidly from the pulmonary
does not produce his or her own memory capillaries into the alveoli. This
establishes more normal blood levels
of O2 and CO2. Because of increased

Appendix D A-15

levels of O2 and decreased levels of blood flow to the brain and could cause Relaxing after a meal helps decrease
CO2 in the blood, the rate of respiratory a person to pass out. Passing out under sympathetic activities and increase
movements is decreased. water could lead to drowning. parasympathetic activities.
6. In severe emphysema, the surface area 1 0. Immediately after the beginning of a 4. Obstruction of the common bile
for gas exchange is reduced, so that not race, runners increase their rate and duct blocks the flow of bile from the
enough O2 can diffuse from the alveoli depth of respiration before blood CO2 gallbladder to the small intestine. As
into the pulmonary capillaries and levels have a chance to increase. The a result, stomach acids are not diluted
not enough CO2 can diffuse from the rate and depth of respiration increase and neutralized to as great an extent
pulmonary capillaries into the alveoli even in anticipation of increased muscular as if bile were present. Lipids are not
when O2 therapy is given. The elevated activity. As a result, for a short time the emulsified by the bile, resulting in
CO2 and the reduced O2 levels in the blood increased rate and depth of respiration decreased lipid digestion and absorption.
both stimulate the respiratory center to can actually cause blood levels of Excretory products, such as bile pigments,
produce an urge to take a breath. CO2 to decrease. The lower levels of cholesterol, and lipids, are not as readily
7. The pH of the body fluids in patients blood CO2 result in a slightly increased removed from the body.
who suffer from untreated diabetes blood pH. After the race has progressed, 5. Introduction of food into the stomach
mellitus decreases (becomes more the increased metabolic activity of the increases the frequency of mass
acidic). A decreasing pH acts as a muscles can produce enough extra CO2 to movements. The mass movements move
strong stimulus to the respiratory center. cause blood CO2 levels to increase above feces into the rectum. Also, during the
Consequently, the rate and depth of resting levels, even with an increased rate night, much of the material in the intestine
respiration increase. The increased rate and depth of respiration. has moved to the lower part of the large
and depth of respiration cause CO2 to be intestine. Mass movements following
released from the circulation at a greater Chapter 16 breakfast, therefore, are more likely to
rate. The lower blood level of CO2 move feces into the rectum. Stretch of the
opposes the reduced pH because of the 1. With the loss of the swallowing reflex, rectum triggers the defecation reflex.
following reaction: vomit can enter the larynx and trachea,
block the respiratory tract, and keep the Chapter 17
CO2 + H2O H2CO3 H+ + HCO3− patient from breathing. Acidic stomach
secretions cause severe inflammation and 1. The recommended daily consumption of
As more CO2 is removed from the blood, swelling of the respiratory passages. saturated fats is less than 20 g. Therefore,
more H+ and HCO3− combine to form the % Daily Value for 2 g of fat is 10%
H2CO3. Removal of the H+ from the 2. Without adequate amounts of hydrochloric (2 / 20 = 0.10, or 10%).
circulation resists a further reduction acid, the pH in the stomach is not low
in the body fluid pH. enough for the activation of pepsin. 2. It is recommended that no more than 30%
This loss of pepsin function results of the daily total kilocaloric intake be fats.
8. When Ima is hyperventilating, the in inadequate protein digestion in the For a 3000 kcal/day diet, that is 900 kcal
stimulus for the hyperventilation is stomach. However, if the food is well (3000 × 0.30). There are 9 kcal/g of fat.
anxiousness, and the anxiousness is more chewed, proteolytic enzymes in the small Therefore, the maximum amount (weight)
important than the CO2 in controlling intestine (e.g., trypsin, chymotrypsin) of total fat consumed per day is 100 g
respiratory movements. As the blood levels can still digest the protein. If the stomach (900 / 9).
of CO2 decrease during hyperventilation, secretion of intrinsic factor decreases, the
vasodilation occurs in the periphery. absorption of vitamin B12 is hindered. 3. From question 2, the teenager’s daily
As a result, the systemic blood pressure maximum amount (weight) of fat
decreases. The systemic blood pressure 3. Even though bacteria apparently consumed per day is 100 g. If he consumes
can decrease enough that the blood flow cause most ulcers, overproduction of a 10-g serving of fat, his % Daily Value is
to the brain decreases. Decreased blood hydrochloric acid because of stress is a 10% (10 / 100 = 0.10, or 10%).
flow to the brain results in a reduced O2 possible contributing factor. Antibiotic
level in the brain tissue, causing dizziness. therapy is an effective treatment, but 4. From question 3, one serving equals
Breathing into a paper bag increases reducing hydrochloric acid production 10% Daily Value. If he eats half of the
Ima’s blood levels of CO2 toward normal. is recommended. Possible solutions contents of the package, he consumes
Because the CO2 does not increase above also include drugs that reduce stomach two servings, or 20% Daily Value.
normal, it does not increase the urge to acid secretion, antacids to neutralize
breathe. The more normal level of CO2 the stomach acid, smaller meals 5. An active person uses many more
prevents the peripheral vasodilation. As (distention of the stomach stimulates kilocalories in a day than a person who
Ima breathes into the paper bag, the acid production), and proper diet. The is not active, and so can lose weight on a
anxiousness is likely to subside. As person should avoid alcohol, caffeine, higher-kilocalorie diet. In addition, some
the anxiousness subsides, the normal and large amounts of protein because people have a higher basal metabolic rate
regulation of respiration resumes. they stimulate acid production. She and tend to burn more kilocalories.
should ingest fatty acids because they
9. Hyperventilating before swimming inhibit acid production, causing the 6. Ingested proteins are digested to amino
decreases the amount of CO2 in the blood. release of gastric inhibitory polypeptide acids in the stomach and intestine and
The decreased amount of CO2 allows and cholecystokinin. Stress also are then absorbed into the circulation.
a longer than normal period of time stimulates the sympathetic nervous The amino acids can be used by cells as
before the swimmer has a strong urge to system, which inhibits duodenal gland building blocks for proteins, which is
breathe. This can be dangerous, however, secretion. As a result, the duodenum has very important if a person is attempting to
because the reduced level of CO2 causes less of a mucous coating and is more build up muscle mass. However, beyond a
vasodilation in the periphery and reduced susceptible to gastric acid and enzymes. certain point, the excess amino acids are
broken down in the liver to make glucose.
These amino acids are, therefore, no more
helpful than any other source of energy.

A-16 Appendix D

If the amount of amino acids is excessive, Both of these changes inhibit ADH Consequently, the H+ accumulate in the
ammonia or keto acids, the breakdown secretion from the posterior pituitary body fluids and decrease the body fluid
products of amino acid metabolism, can gland. The reduced ADH levels in the pH. The rate and depth of respiration
accumulate to toxic levels. blood cause the kidney to produce a large increase because a decreased body fluid
7. Lotta Bulk’s urine would have more urea volume of dilute urine. pH stimulates the respiratory center.
than before she began the high-protein diet. 2. The sodium chloride increased the The decrease in the body fluid pH causes
Excess protein is metabolized and used as concentration (osmolality) of his blood the kidneys to secrete additional H+
a source of energy. One of the breakdown without affecting the volume of blood. into the nephron. Therefore, the pH
products of protein is ammonia. Ammonia The increased concentration (osmolality) of the urine decreases.
is toxic, so it is converted in the liver to of his blood stimulated ADH secretion
urea, which is carried by the blood to the from the posterior pituitary gland. The 7. While Spanky held his breath, CO2
kidneys and eliminated. ADH caused the kidney to produce a accumulated in his body fluids. The
8. As ATP breakdown increases, more ATP is small volume of concentrated urine. increased CO2 combined with water
produced to replace what is used. Over an 3. The excessive sweating results in a to form carbonic acid that, in turn,
extended time, the ATP must be produced reduced blood volume and the blood produced H+ and HCO3−. The increased
through aerobic respiration. Therefore, has a greater than normal concentration concentration of H+ in the body fluids
O2 consumption and basal metabolic (osmolality). Both of these changes caused the pH of the body fluids to
rate increase. The production of ATP stimulate ADH secretion from the decrease. After 2 minutes, the reduced
requires the metabolism of carbohydrates, posterior pituitary gland. The ADH acts on pH and increased body fluid CO2 levels
lipids, or proteins. As these molecules are the kidney to produce a small volume of strongly stimulated the respiratory
used at a faster than normal rate, body concentrated urine. center to increase the rate and depth
weight decreases. Increased appetite and 4. Excessive urine production, low blood of respiration. The increased rate of
increased food consumption resist the pressure, high plasma K+ levels, but respiration reduced the body fluid CO2
loss in body weight. As ATP is produced not high plasma Na+ levels, result. Low levels and increased the body fluid pH
and used, heat is released as a by-product. aldosterone levels result in excessive back toward its normal value. The kidneys
The heat raises body temperature, which is loss of Na+ in the urine. The Na+ attract did not respond to the change in pH
resisted by the dilation of blood vessels in water molecules from the peritubular within 2 minutes. The kidneys are more
the skin and by sweating. capillaries into the nephron, which results powerful regulators of body fluid pH,
9. No, this approach does not work because in a greater than normal urine volume. but they require several hours to become
he is not losing stored energy from The loss of Na+ in the urine reduces maximally active.
adipose tissue. In the sauna, he gains the plasma Na+ concentration. The loss
heat, primarily by convection from the of water in the urine reduces the blood 8. Martha’s blood pH increased. Her
hot air and by radiation from the hot volume and therefore reduces the blood frequent vomiting resulted in the loss of
walls. The evaporating sweat is removing pressure. Because aldosterone causes Na+ H+ from her stomach and an increase in
heat gained from the sauna. The loss of reabsorption from the nephron and K+ HCO3− in her blood. Since Martha lost
water will make him thirsty, and he will secretion into the nephron, K+ accumulate fluid from her body and she consumed
regain the lost weight from drinking in the plasma. no fluid, the concentration of her body
fluids and eating foods containing water. 5. The following all decrease the blood fluids increased and her blood volume
1 0. Drinking cool water could help in two pressure in the glomerular capillaries decreased. Consequently, ADH secretion
ways. Because the water is cool, raising and therefore decrease the glomerular increased. Because blood volume
the water to body temperature requires filtration rate: decreased blood pressure decreases, the blood flow to the kidneys
the expenditure of energy. Also, stretch and increased sympathetic stimulation decreases. This stimulates renin secretion
of the stomach decreases appetite (see that constricts the renal arteries and from the kidney. This, in turn, converts
chapter 16). the afferent arterioles. Blocking the angiotensinogen to angiotensin I.
1 1. During fever production, the body nephron causes the capsule pressure Angiotensin I is converted to angiotensin II,
produces heat by shivering. The body in the nephron to increase, so that it is which stimulates aldosterone secretion
also conserves heat by constricting blood equal to the pressure in the glomerular from the adrenal cortex. In response to
vessels in the skin (producing pale skin) capillaries, which reduces the filtration an increase in blood pH, the kidneys
and by reducing sweat loss (producing dry rate. An increase in plasma proteins also decrease their rate of H+ secretion and
skin). When the fever breaks—that is, “the decreases the filtration rate. The increased HCO3− reabsorption. Consequently,
crisis is over”—heat is lost from the body plasma protein concentration attracts this causes an increase in blood H+
to lower body temperature to normal. water by osmosis and therefore reduces concentration and a decrease in blood
This is accomplished by dilation of blood the tendency for water to pass from the HCO3−. The kidney’s response to changes
vessels in the skin (producing flushed glomerulus to Bowman capsule. in pH takes many hours, but it has a large
skin) and increased sweat loss (producing 6. Removal of a large amount of bicarbonate capacity to maintain pH homeostasis.
wet skin). ion (HCO3−) from the body fluids causes
a decrease in the body fluid pH because Chapter 19
Chapter 18 there are fewer HCO3− to combine with
hydrogen ions (H+) according to the 1. Removing the testes eliminates the
1. The rate of urine production increased following formula: source of testosterone. Therefore, blood
over the next 2 hours, and the urine was levels of testosterone would decrease.
dilute. The water he consumed increased CO2 + H2O H2CO3 H+ + HCO3− Because testosterone has a negative-
his blood volume and decreased the feedback effect on the hypothalamus
concentration (osmolality) of his blood. Carbon Water Carbonic Hydro- Bicarbon- and pituitary gland, GnRH, FSH, and
LH secretion increases and the blood
dioxide acid gen ion ate ion levels of these hormones increase.

Appendix D A-17

2. The estrogen and progesterone in birth 6. A drug that blocks the effect of “budding” period; limb buds and other
control pills inhibit the large increase in progesterone on its target tissues will cause “buds” have just formed (see table 20.2).
LH secretion from the anterior pituitary, the tissue to respond as if no progesterone 2. At 35–45 days post-LMP, the embryo would
which is responsible for ovulation. were present. Progesterone is secreted be 21–31 days old, which overlaps the
Without the large increase in LH by the corpus luteum for about 7 days period of neural tube closure (18–26 days).
secretion, ovulation cannot occur. after ovulation. The progesterone affects A high fever during this period could
the endometrium of the uterus and, in prevent neural tube closure in the embryo,
3. E is the correct answer. The secretory response, the endometrium becomes so that the newborn baby may have
phase of the menstrual cycle occurs after prepared for implantation. A decline neural tube defects, such as anencephaly
ovulation. It is following ovulation that in progesterone causes menstruation (open neural tube in the area of the brain,
the corpus luteum forms and produces to occur. If a drug is taken 3–4 days resulting in absence of the upper brain)
progesterone. In addition, the progesterone following ovulation that blocks the effect or spina bifida (open spinal cord resulting
acts on the endometrium of the uterus of progesterone, the endometrium will from failure of the neural tube to close in
to cause its maximum development. not become fully prepared for implantation that area).
Therefore, progesterone secretion reaches and menstruation will begin early. If a 3. The correct answer is A. Prolactin is
its maximum levels and the endometrium drug that blocks progesterone is taken by responsible for the production of milk by the
reaches its greatest degree of development a woman who is pregnant, the effect will breast. Surges of prolactin are stimulated by
during the secretory phase of the be to cause the endometrium to slough. the process of suckling and are required to
menstrual cycle. This is similar to the events that occur maintain milk production. Drugs that inhibit
during menstruation. If this occurs, it will prolactin release will cause the breast to
4. D is the correct answer. Between terminate the pregnancy. Progesterone cease milk production after a few days.
approximately 12 and 14 days of the is necessary to maintain pregnancy. 4. Yes. Because dimpled cheeks are
menstrual cycle, you would normally The corpus luteum of the ovary secretes dominant, a person with dimpled cheeks
expect increasing blood levels of estrogen progesterone until the end of the first may have a genotype of Dd (D being the
and LH. In the average menstrual cycle, 3 months of pregnancy; prior to the third dominant gene for dimples and d being the
ovulation occurs on day 14. Prior to month of pregnancy, the placenta begins to normal gene). If two Dd, dimpled people
that time, estrogen levels are increasing. secrete progesterone. The placenta becomes have a child, there is a 25% probability
The increasing estrogen stimulates LH the primary source of progesterone after that the child would not have dimples (dd).
secretion. The increasing LH, in turn, the third month of pregnancy. 5. No, not without additional information.
causes increased estrogen secretion To be able to roll their tongue into a tube,
from the developing follicle. Blood 7. During menopause, estrogen and both mother and son need to have only
progesterone levels are low at this time. progesterone are produced by the ovary one dominant gene. The son could inherit
Progesterone is not secreted in large in only small amounts. Consequently, this dominant gene from his mother, so it
amounts until the corpus luteum is estrogen and progesterone levels in the is possible that his father is a non–tongue
formed after ovulation. blood are low. These hormones have a roller. It is also possible that his father is
negative-feedback effect on the secretion a tongue roller, but there is no proof for
5. E is the correct answer. On day 15 of of FSH and LH from the anterior pituitary either hypothesis.
the menstrual cycle, one would expect gland. Therefore, in the absence of 6. Hemophilia is an X-linked recessive gene.
decreasing blood levels of LH, decreasing estrogen and progesterone, FSH and LH A female must have the genotype XhXh
blood levels of estrogen, and increasing are secreted in greater amounts and the to have hemophilia, whereas because
blood levels of progesterone. In the blood levels of FSH and LH increase. males have only one X chromosome, a
average menstrual cycle, ovulation occurs However, there is no large increase in single hemophilia gene will cause them
on day 14. After ovulation, the ovulated LH, like the increases that occur prior to to have the disorder (XhY). For their
follicle develops into the corpus luteum. ovulation. The average concentration of daughter to have hemophilia, she would
Estrogen levels decrease as the follicle LH and FSH is greater than the levels that have the genotype XhXh. That would
is converted to the corpus luteum. The occur either before or after ovulation. mean she inherited the Xh gene from both
corpus luteum secretes progesterone parents. Since the mother does not have
in increasing quantities and small Chapter 20 hemophilia, she is a carrier and must be
amounts of estrogen as the corpus luteum XXh. The father’s genotype must be XhY
develops. The increasing blood levels of 1. Fertilization occurs approximately 14 days (he has hemophilia).
progesterone inhibit LH secretion from after the LMP, so the embryo in this case
the pituitary gland. Consequently, blood is 30 days old. It has just completed the
levels of LH fall to low levels.

Appendix E

Answers to Predict Questions

Chapter 1 relationship to each other. Thus the nose protons. Therefore, there are 9 protons in
is always referred to as being superior to fluorine. Since the number of electrons
2. To answer this question, you must first the mouth. in an atom is the same as the number of
realize that regulation of our body’s 5. To determine the proper quadrants of protons, there are 9 electrons. To find
environment is due to homeostatic these organs, it is important to know the number of neutrons of any element,
mechanisms. These mechanisms work that the positions of organs in the body subtract the atomic number from the
to keep variables near their set point. In are consistent from person to person. mass number (19 − 9 = 10). So there are
this chapter, you learned that in order to Referring to figures 1.2 and 1.10a, it 10 neutrons.
keep body temperature near its set point, is simple to answer this question. Just 4. A fun, easy way to remember how loss
the control center (the hypothalamus), remember to use the organs in figure of electrons affects the charge of an
receives input from thermoreceptors in 1.10a as reference points when comparing atom is to ask: “Atom, are you sure you
the skin. The hypothalamus would then to organ positions in figure 1.2. Thus, lost an electron?” Atom: “I’m positive.”
instruct the effectors (the sweat glands), spleen: left-upper; gall bladder: right- Therefore, we know that the charge on an
to produce sweat if body temperature upper; left kidney: left-upper; right kidney: iron ion would be positive. The charge is
had risen too high. So, for this question, right-upper; stomach: mostly left-upper; also equal to the number of electrons lost,
you can predict that swimming in cool liver: mostly right-upper. in this case, 3. Therefore, the iron’s charge
water would prevent the hypothalamus 6. The first step is to define the would be +3 and the symbol is Fe3+.
from stimulating the sweat glands to abdominopelvic and peritoneal cavities. 5. To answer this question, you must recall
produce sweat. The next part of the The abdominopelvic cavity is located the relationship between CO2, H2O, and
question asks what would happen if inferiorly to the diaphragm and superiorly H+ in solution. Carbon dioxide readily
this mechanism was not sufficient to to the pubic symphysis. The peritoneal combines with water, resulting in the
maintain normal body temperature. In cavity is located between the visceral production of free H+. Therefore, as the
other words, if you were swimming in peritoneum, which covers organs in the amount of CO2 decreases, the reversible
cool water, the thermoreceptors would abdominopelvic cavity, and the parietal reaction will shift in the other direction
cause the hypothalamus to initiate peritoneum, which lines the wall of to form CO2. Similar to the trough of
shivering. Simply preventing sweating the abdominopelvic cavity. So, look at water example, if CO2 levels decrease,
was insufficient to keep body temperature figure 1.15c and take notice of the bright it’s like raising the right side of the
from dropping out of its normal range. If white area. This is the peritoneal cavity trough causing water to flow to the
shivering continued to be ineffective, the containing only peritoneal fluid. You can left. The reaction “flows” to the left:
body would conserve heat through loss see that, although the peritoneal cavity is CO2 + H2O ← H+ + HCO3−. In order for
of consciousness and severe hypothermia around these organs, they are not within this to happen, free H+ combines with
could set in. the peritoneal cavity. Secondly, looking HCO3− decreasing its level in the blood.
at the right side of figure 1.15c again, Section 2.3 explains that this decrease in
3. To answer this question, you must first notice there are organs behind the parietal H+ levels changes the acidity of the blood
recall the major difference between peritoneum, but inside the abdominopelvic so that it becomes more basic.
negative-feedback mechanisms and cavity. These organs are also not within 6. During exercise, your body is doing
positive-feedback mechanisms. Negative the peritoneal cavity and are considered work by muscular contractions. Work
feedback returns a variable to its set retroperitoneal (e.g., the kidneys). involves converting one form of energy
point while positive feedback keeps into another, and as you read in the
a variable different from its set point. Chapter 2 previous section, this conversion is not
Also, you read that the body cells’ 100% efficient. As a result, heat energy
internal fluid and solute environment 2. The question asks you to differentiate is released. When you contract your
is maintained within a narrow range. between mass and weight. First, consider muscles, potential energy is converted
When you are thirsty your impulse is to the definitions. Weight, in particular, to kinetic energy and heat energy. Thus,
drink something, thereby adding fluid to is dependent on the force of gravity. more heat is produced than when at rest,
your body. This is a negative-feedback Therefore, if an astronaut is in outer and your body temperature increases.
mechanism because drinking fluids space, where the force of gravity from 7. To answer this question, first consider the
restores blood volume and pressure. earth is nearly nonexistent, the astronaut pH scale. It’s important to realize that it
When these variables return to normal is “weightless.” However, the definition of is an inverse scale. In other words, a high
you no longer feel thirsty. mass is the amount of matter present in the concentration of H+ (acid) is represented
object itself. Thus, no matter the location of by a low pH value. For example, a pH
4. In order to recognize which correct term an object, the mass remains constant. of 2 means there are many free H+ in the
to use here, you must first realize that solution. The question asks what will
directional terms are relative terms to the 3. The question asks you to predict the happen to the pH value if a base is added
body. Therefore, it doesn’t matter what atomic structure of fluorine. By definition,
position your body is in compared to the the atomic number (9) is the number of
earth, body parts always have the same

A-18

Appendix E A-19

to a solution. Because bases combine with ribosomes, carries out the synthesis of Chapter 4
H+, there will be less free H+ and the pH proteins that will be released from the cell.
value will increase. To evaluate the effect The Golgi apparatus is also involved in 2. a. The question asks about the relationship
of a buffer, it’s necessary to know that a the packaging of cellular materials that are between form and function of tissues.
buffer is a chemical that resists changes secreted by packaging the proteins into First, consider the name of the
in pH. In an acidic solution, a buffer will secretory vesicles that move to the plasma tissue type: nonkeratinized stratified
act as a H+ reservoir, releasing H+ when a membrane. (b) Active transport requires epithelium. The term stratified means
base is added. The released H+ combines ATP to move materials across the cell more than one layer of cells, whereas,
with the base to inhibit or even prevent the membrane, so we would expect the cell the term simple means a single layer of
solution from becoming more basic. to have many mitochondria to produce cells. In the digestive tract, a principal
ample ATP. (c) Cells that ingest foreign function is absorption, a process that
Chapter 3 substances by endocytosis would require would be hindered by the many layers
the enzymes needed to break down those of stratified epithelium. Stratified
2. First, we need to consider the normal substances. We learned that lysosomes are epithelium is more suited to areas where
process and identify the intracellular and vesicles of digestive enzymes that break the layers would protect underlying
extracellular areas involved. We are told down materials brought into the cell. tissues from abrasion. Columnar
that urea diffuses from liver cells, which 6. Recall from “Gene Expression” that a cells are specialized for secretion and
is the intracellular region, to the blood, gene is a sequence of DNA nucleotides absorption. These cells contain a large
which is the extracellular region. This also that provides the instructions for making number of organelles that produce the
defines the direction of urea diffusion, a specific protein. We also learned that the secretions and transporters needed to
from the area of higher urea concentration sequence of DNA nucleotides determines support absorption.
inside the cells to the area of lower urea the sequence of RNA nucleotides of
concentration in the blood. The kidneys an mRNA, which then determines the b. In this scenario, both tissue types are
remove the urea from the blood; therefore, sequence of amino acids of a protein stratified, but one type lacks keratin.
if the kidneys stopped functioning, the in the processes of transcription and The protein keratin provides a tough
concentration of urea in the blood would translation, respectively. We also learned layer that retards water movement.
increase. Eventually, this would eliminate that the information in mRNA is carried If keratin were absent from the
the urea concentration gradient or even in three nucleotide groups called codons, epidermis, the body could not retain
reverse it. Urea would remain in the cells which specify a particular amino acid or water effectively and would be more
and increase to toxic levels that could signal the end of translation. So, if one prone to damage from abrasion.
damage or even kill the cells. nucleotide in a DNA molecule is changed,
that one codon in the mRNA molecule 3. The question asks how the structure of
3. Remember that diffusion, whether simple will also be changed. This can lead to a tissue’s components contributes to its
or facilitated, is the movement of a several different outcomes. Since an function. When a muscle contracts, the pull
substance down its concentration gradient. amino acid can often be specified by more it exerts is transmitted along the length of
That means that the glucose concentration than one codon, the changed nucleotide its tendons. The tendons need to be very
gradient between the extracellular fluid and may not change the amino acid and hence strong in that direction but not as strong
the cytoplasm depends on the amount of the protein structure will not be affected. in others. The collagen fibers, which are
glucose molecules only and is not affected Alternatively, the changed nucleotide may like microscopic ropes, are therefore all
by other molecules, even if they are similar. change the codon to specify a different arranged in the same direction to maximize
If glucose is converted to other molecules amino acid. This single amino acid change their strength. In the skin, collagen fibers
inside the cell, the concentration gradient could in turn change the protein structure. are oriented in many directions because
is maintained and the cell can continue to Depending on the changed amino acid, the skin can be pulled in many directions.
take up more glucose. the structural change could be subtle or The collagen fibers can be somewhat
severe. Finally, the changed nucleotide randomly oriented, or they can be
4. In the description of cystic fibrosis we learn could create a new stop codon or eliminate organized into alternating layers. The
that it is the result of defective chloride ion an existing stop codon. These changes fibers within a layer run in the same
channels that fail to transport Cl− out of would very likely cause dramatic changes direction, but the fibers of different layers
cells. This description allows us to easily in the protein structure since a premature run in different directions, similar to steel
predict the effect on Cl− concentrations stop codon would cut the protein short and rods of rebar in a concrete structure.
inside and outside of the cell, because ion removal of a stop codon would add extra
channels allow ions to diffuse down their amino acids not normally in the protein. 4. The question tells you that: (1) vitamin C
concentration gradients. The concentration 7. Recall that after cell division, the is required for collagen formation; (2) scars
of Cl− would remain higher inside the cell new cells undergo the process of are formed from collagen; and (3) there is
and lower outside the cell. differentiation, which is when the cell a lack of vitamin C. Therefore, if there is a
develops the specialized structures and lack of vitamin C, the density of collagen
5. To answer this question, we must first functions of a mature cell. As a result, fibers in a scar may be reduced and the
consider the functions involved in each cells of different tissues do not all look scar may not be as durable as a normal scar.
cell described and identify the organelles the same. If cancer cells are continuously
that carry out these functions. Referring dividing, they do not undergo this 5. There is more than one way to organize a
to table 3.1 would help to quickly identify differentiation process and therefore do table that summarizes the characteristics
the organelles and functions. (a) Cells not appear the same as a mature cell of of the major muscle types. See the
that synthesize and secrete proteins the specific tissue. following table.
would require organelles involved in the
manufacturing, packaging, and releasing 6. First, define inflammation. Inflammation
of proteins from the cell. The rough produces five main symptoms: redness, heat,
endoplasmic reticulum, with the attached swelling, pain, and disturbance of function.
These symptoms occur because of an
increased blood flow to the area. However,

A-20 Appendix E

table E.1 Major Characteristics of the Three Muscle Types

Muscle Nuclei in Location Control Cell Shape Striated Branching
Type Each Cell of Nuclei Fibers
Voluntary Long and cylindrical Yes
Skeletal Many Peripheral Involuntary Yes No
Cardiac One Central Branching cylinders joined Yes
Involuntary by intercalated disks No
Smooth One Central No
Spindle-shaped cells

if the area is so badly damaged that blood will have a pinker appearance due to the urine output, the nurse can determine if he
vessels are destroyed, no inflammation lack of calluses and a thinner stratum is getting enough fluids. If his urine output
occurs in the damaged site. However, in corneum. (c) The posterior surface of the is too low, more fluids can be given.
the surviving tissues surrounding the dead forearm is usually darker than the anterior
tissue, inflammation occurs. surface of the forearm. Recall that the Chapter 6
7. The question asks why stitches are helpful pigment melanin contributes to the darker,
for healing a wound with a large space tanned appearance of skin. Also, melanin 2. In the previous section, you learned that
between the edges. Sutures bring the production increases with sun exposure. the minerals of bone give it weight-bearing
edges of a wound closer together so that The posterior surface of the arm is usually strength much as concrete provides
there is (1) less space for regenerating exposed to more sunlight than the anterior strength to columns of a bridge. Without
cells to fill in; (2) a lower risk of infection; surface, so we would expect more melanin the minerals, the bone matrix would consist
(3) a reduced amount of granulation tissue production and a darker appearance on the of only collagen and would be overly
formation; and (4) a faster healing time. posterior surface. flexible—it could be tied into a knot. On
Additionally, the smaller amount of scar 4. Recall that hair color is determined by the the other hand, you learned that collagen
tissue and wound contracture lessens the production and distribution of melanin springs back to its original shape after it
visibility of the wound site later on. by melanocytes in the hair bulb. Also, has been bent. Therefore, without collagen,
remember that hair growth begins at the bone would be too brittle and would easily
Chapter 5 hair bulb and that the pigmented cells break. Collagen loss is one reason the
are pushed farther and farther away from bones of many older people break easily.
2. In the description of the epidermis, the the hair bulb, as the hair grows longer.
superficial layer of the skin, we learned This would make it impossible for Marie 3. Without cartilage growth, the long bones
that the keratinized cells are coated with Antoinette’s hair to suddenly turn white; will be shorter than normal. Bone growth
lipids to prevent fluid loss. Recall from only new hair growth would show the loss occurs in the epiphyseal plate. As you
chapter 3 that substances that are lipid- of pigment. Since it takes quite a while for learned, the epiphyseal plate is a section of
soluble easily diffuse through lipid layers hair to grow, it is impossible that her hair hyaline cartilage between each epiphysis
but water-soluble substances do not. By could turn white in one day. and the diaphysis. In order for bone to
applying the same principles of diffusion 5. Recall that the redness of skin is due to grow in length, the hyaline cartilage in
across cell membranes to diffusion across increased blood flow through the skin. Also, the epiphyseal plate must first increase in
the skin, we can predict that lipid-soluble we learned that blood flow determines the thickness and can then be replaced by bone
substances diffuse easily but water-soluble distribution of heat to different regions of with the action of osteoblasts. However,
substances do not. the body. The red appearance of the nose bone thickness does not require cartilage
and ears indicates increased blood flow growth to occur first. Therefore, an adult
3. Recall that skin color is determined by in these areas, and we can assume that that lacked cartilage growth in the long
three factors: skin pigments, blood flow in this leads to warming of this tissue that is bones during childhood would have
the skin, and the thickness of the stratum probably very cold due to the weather. much shorter bones than normal, but their
corneum. We should consider these three 6. We learned that one of the functions of the bones would be the same diameter, or even
factors for each of the comparisons. skin is to reduce water loss. Sam’s burns thicker than normal. One type of dwarfism
(a) The lips are pinker or redder than the resulted in severe damage to his skin, exemplifies this. The person’s head and
palms of the hands. The skin of the palms which most likely led to increased water trunk are normal in size, but the long
of the hands is much thicker than the skin loss at the injury site, causing dehydration bones of the limbs are very short.
of the lips. As a result, the redness due to and reduced urine production. We learned
blood flow is more visible in the thinner that Sam was administered a large volume 4. Tears run over the surface of our eyes and
skin of the lips than in the thicker skin of of fluid to counteract his increased fluid enter the nasolacrimal duct, which empties
the palms of the hand. (b) The palms of the loss. But how much fluid should be given? into the nasal cavity. Therefore, when
hands of a person who does heavy manual The amount of fluid given should match our eyes are producing more tears than
labor are more likely to be calloused and the amount that is lost, plus enough to normal, the increased liquid in our nasal
therefore have a thicker stratum corneum. keep the kidneys functioning properly. An cavity causes a “runny nose.”
The thicker stratum corneum masks the adult receiving intravenous fluids should
redness due to blood flow and will also produce 30–50 mL of urine per hour, and 5. Just before the swimmer begins the power
have more carotene pigmentation, so the children should produce 1 mL/kg of body stroke, the arm is flexed (close to the body)
palms will appear paler with a yellowish weight per hour. By monitoring Sam’s and medially rotated (towards the center
tint. The palms of the hands of the person of the body) and the forearm is extended
who does not do heavy manual labor (away from the body) and pronated (palm
down). During the power stroke, the arm
is powerfully extended (pushed away from

Appendix E A-21

the body), slightly abducted (moved away produce ATP faster than can aerobic. axons carry action potentials from
from center), and medially rotated (towards However, anaerobic respiration can peripheral tissues to the central nervous
the center of the body). During the only produce ATP for 2–3 minutes and system (CNS), which includes the brain
recovery stroke, the arm is circumducted can’t be maintained. Because muscles and spinal cord. Motor axons carry action
(circled around the shoulder towards the replenish O2 and glucose stores after potentials from the CNS to peripheral
back), laterally rotated (moved away from physical exercise, aerobic respiration and tissues. Now, identify the types of axons
the center of the body), and flexed (brought breathing rate remain elevated. This can in each structure listed. Spinal nerves,
closer to the body) in preparation for the be thought of as repaying the O2 deficit. recall, have both sensory and motor axons,
next stroke. The forearm is flexed (close 4. Referring to figure 7.16 will help you so action potentials are propagated both to
to the body) during the first part of the answer this question. Raising eyebrows— the spinal cord and away from the spinal
recovery stroke and extended (away from occipitofrontalis; winking—orbicularis cord. Dorsal roots contain only sensory
the body) during the last part. oculi; whistling—orbicularis oris and axons, so action potentials are conducted
6. Hopefully, Betty will discourage her buccinators; smiling—zygomaticus; to the spinal cord only. Finally, ventral
granddaughter from smoking as it reduces frowning—depressor anguli oris; roots contain only motor axons, so action
estrogen levels. Lowered estrogen sneering—levator labii superioris. potentials are conducted away from the
levels, as you learned while reading the 5. Shortening the right sternocleidomastoid spinal cord.
background information, are a major muscle rotates the head to the left and 4. Recall that the phrenic nerve innervates
contributor to osteoporosis. Additionally, slightly elevates the chin. the diaphragm allowing for the contraction
Betty should encourage her granddaughter 6. In the sprinter’s stance and the bicyclist’s necessary for breathing. If the right phrenic
to get adequate calcium and vitamin D in racing posture, the thigh is flexed at a nerve was damaged, then we would expect
her diet and to get some sunscreen-free 45-degree angle because at that angle lack of muscle contraction in the right half
sun exposure for vitamin D production (no the gluteus maximus functions at its of the diaphragm affecting breathing. To
more than 20 minutes a day). Betty and maximum in extending the thigh, thus answer the second part of the question,
her granddaughter might consider taking providing maximum force. we need to consider the location of spinal
a yoga class together as well. Exercise 7. DMD affects the muscles of respiration cord injury to predict the effect it would
is an important source of increased bone and causes deformity of the thoracic have on the diaphragm. Remember that the
density because it causes the muscles to cavity. The reduced capacity of muscle phrenic nerve is part of the cervical plexus,
put stress on the bones, which thickens tissue to contract is one factor that reduces which includes spinal nerves C1–C4. If
the bones. Because the greater the density the ability to breathe deeply or cough the spinal cord is completely severed in
of bone before the onset of osteoporosis, effectively. In addition, the thoracic cavity the thoracic region, the phrenic nerve
the more tolerant it is to bone loss, most can become severely deformed because would not be damaged and the diaphragm
people (especially women in their 20s and of the replacement of skeletal muscle would not be affected. On the other hand,
30s) need to make sure to get adequate with connective tissue. The deformity can if the spinal cord is severed in the upper
calcium and exercise. reduce the ability to breathe deeply. DMD cervical region, the phrenic nerve would
can also affect the muscle of the heart and be damaged and the contractions of the
Chapter 7 cause heart failure. diaphragm would not occur, eliminating
the person’s ability to breathe. Death
2. To predict a mechanism for anesthetic Chapter 8 would likely occur if medical assistance
activity, you must first understand was not administered quickly.
how action potentials are initiated and 2. To answer this question, let’s first describe 5. We need to consider the functions of
propagated in electrically excitable cells. the Na+ concentration and its role in a the medulla oblongata first to answer
In this chapter, you learned that in both normal excitable cell. We learned that in this question. Recall that the medulla
nerve cells and muscle fibers, it is Na+ a normal cell, the concentration of Na+ is oblongata contain nuclei that regulate heart
entry that depolarizes the cell membrane much higher outside the cell than inside rate, blood vessel diameter, breathing,
to threshold. Now, recall that at threshold, the cell. As a result, when Na+ channels swallowing, vomiting, coughing, sneezing,
it is the opening of voltage-gated Na+ open Na+ diffuses into the cell quickly balance, and coordination. Compression
channels that creates the action potential. causing the changes in the membrane of the medulla could cause damage to
Thus, you can predict that in order for potential that result in an action potential. these nuclei and lead to other problems
an anesthetic to prevent action potential The movement of Na+ into the cell is the in the body. Changes in the regulation of
formation, it prevents Na+ channels from result of its steep concentration gradient. heart rate, blood flow, and respiration are
opening. Without Na+ entry, there is no Remember, also, that enough Na+ must the most life threatening. The cells of
action potential and no transmission of enter a cell for the membrane potential the body require adequate levels of O2
information, such as pain. to reach threshold, opening the voltage- and nutrients to maintain homeostatic
regulated Na+ channels and causing conditions. Blood flow and respiration
3. We learned that aerobic respiration is an action potential. If the extracellular are vital functions and interference with
the principal energy source for resting concentration of Na+ is reduced, then either may inhibit normal homeostatic
muscles or muscles undergoing long- the concentration gradient would also be functions. If not corrected, the loss
term exercise; therefore, a 10-mile run reduced. The effect would be that if the of homeostasis results in death.
requires aerobic respiration, which cell is stimulated, less Na+ would enter the Interestingly, the heart can continue to
can provide a consistent source of cell. The cell would not reach threshold beat, even if the medulla oblongata is
ATP. However, during the sprint, the and an action potential would not occur. damaged. However, blood pressure would
intense contraction of the muscles uses most likely drop, resulting in shock,
ATP faster than aerobic respiration 3. First, refer to figure 8.2 to see the which can ultimately result in death.
can replace it, and thus anaerobic direction of action potential propagation in
respiration is beneficial because it can sensory axons and motor axons. Sensory

A-22 Appendix E

6. To answer this question, we need to first 8. In this chapter, we learned that the question to include whether or not the
identify the type of sensation, the area of right side of the body is monitored and person is looking at a distant object or
the cerebrum that detects this sensation, controlled by the left side of the brain. The a near object. As the person is driving a
and the association area that allows for crossing over of axons from one side of car, she is looking at distant objects down
recognition of the object based on past the brainstem or spinal cord to the other the road. She then looks down to see the
experience. A person that is blindfolded side of the brainstem or spinal cord results near speedometer, and then back to the
would use the sense of touch to gather in this pattern of regulation. Since Scott distant objects down the road. Recall
information about the object in order to exhibited loss of skeletal muscle movement that the lenses change shape to focus on
describe it. Sensations from the skin of and sensations on his right side, we can objects that are either distant or near.
the hand are sent via sensory neurons to conclude that the left side of the brainstem Now consider the changes that occur to
the dorsal horn of the spinal cord. The was more severely affected by the stroke. the eye, particularly the lens, in the series
signals are then relayed to spinal cord of events. Referring to figure 9.15 will
neurons and transmitted to the brain. Chapter 9 also help in answering this question. As
We learned earlier that in the brain, she is looking at the road (distant), the
the sense of touch is perceived in the 2. To answer the first part of the question, ciliary muscles of the ciliary body are
primary somatic sensory cortex of the we must recall the types of pain and the relaxed, the tension in the suspensory
parietal lobe of the cerebrum and that the types of structures associated with each ligaments is high, and the lenses of
somatic sensory association area allows type of pain. Constipation is causing pain the eyes are flattened. When she looks
for recognition of the stimulation. The associated with the colon, a deep structure. at the speedometer (close), the ciliary
information is passed from the primary Remember that the deeper structures muscles contract, reducing the tension
somatic sensory cortex to the somatic lack tactile receptors, so the type of pain in the suspensory ligaments, causing the
sensory association area, where she will experienced is diffuse. We also learned lenses to thicken. When she looks back
recognize the characteristics of the object. after reading “Referred Pain” that the pain to the road (distant), the ciliary muscles
Now, that she has recognized the object, associated with deeper structures is usually relax again, increasing the tension in the
we need to describe the pathway involved felt in more superficial structures. Using suspensory ligaments, causing the lenses
in determining a word and initiating the figure 9.2, we can predict that the man feels to flatten again.
muscle contractions necessary to say the the pain around his navel, the common area 7. When you hear a faint sound, you turn
word. This occurs when action potentials for referred pain associated with the colon. your head toward it because sound waves
travel to the sensory speech area, where are collected by the auricle and conducted
the object is given a name. From there, 3. We have all probably had a cold and know through the external auditory canal to the
action potentials travel to motor speech that a common symptom is a stuffy nose, tympanic membrane. The shape of the
area, where the spoken word is initiated. making it hard to inhale through the nose. auricle is such that sounds coming from
Action potentials from the motor speech This also affects our ability to smell. Recall the side and front of the head are most
area travel to the premotor cortex and then that many taste sensations are strongly efficiently conducted into the external
to the primary motor cortex, where action influenced by olfactory sensations. If our auditory canal. Turning the head toward
potentials are initiated that stimulate the sense of smell is decreased, our sense of the sound helps maximize accumulation
muscles necessary to formulate the word. taste will also decrease. of the sound waves by the ear. In addition,
because the sound reaches each ear at a
7. The autonomic nervous system maintains 4. After reviewing the section “Lacrimal slightly different time, you can localize
homeostasis by adjusting body activity Apparatus,” we understand that tears from the origin of the sound. Remember also
to different levels of stress and activity. the surface of the eyeball drain through that reflexes integrated in the superior
Recall that the sympathetic division of the lacrimal caniculi into the lacrimal colliculi cause the head and therefore the
the autonomic nervous system, often sac, which empties into the nasal cavity eyes to turn toward a sound, so that you
called the fight-or-flight system, prepares through the nasolacrimal duct. Our can see what is making the sound as well.
the body for physical activity but also sense of smell is due to the presence of 8. We learned that the brain compares sensory
prepares the body for stressful situations. olfactory receptors in the nasal cavity. If input from the semicircular canals, eyes,
The parasympathetic division, often called medications are placed into the eyes, some and proprioceptors in the back and lower
the rest-and-digest system, is consistent may drain into the nasal cavity, which may limbs and that conflicting information can
with resting conditions. Keeping these stimulate the olfactory receptors of the cause motion sickness. If you close your
descriptions in mind and referring to olfactory organ. Our sense of taste is due eyes, one of these sources of information
table 8.8, we can easily answer this to the presence of taste receptors in the is eliminated and the brain has less
question. (a) A person who is extremely mouth and pharynx. The ability to “taste” conflicting input to compare, reducing
angry is experiencing a stressful situation the medication is due to the fluid draining the probability of motion sickness. We
and we would expect changes in the body from the nasal cavity into the pharynx can perceive more motion in close objects
associated with sympathetic activity to stimulating taste receptors. than in distant objects, so looking at the
occur. Examples include increased heart horizon would also reduce the visual input
rate, increased breathing rate, dilation 5. Recall that there are two types of of perceived motion to the brain and reduce
of pupils, and decreased digestive and photoreceptors that allow for the sense of the probability of motion sickness.
urinary functions. (b) A person who has vision. We learned that cones allow for
just finished eating and is now relaxing color vision and require more light for Chapter 10
would exhibit changes associated with stimulation, whereas rods allow for black-
the parasympathetic division. Examples and-white vision and can function in dim 2. The description of the drug is very
include decreased heart rate, decreased light. Hence, in dim light primarily rods, important to determining the function of
breathing rate, constriction of pupils, and and not cones, are stimulated, so that we the hormone that it affects. First, the drug
increased digestive and urinary functions. see objects in shades of gray, not in color. is lipid-soluble. Recall that many lipid-

6. This question addresses changes that
occur in the eye as a person looks at things
far away and close up. Let’s rephrase the

Appendix E A-23

soluble hormones bind to intracellular reabsorption and water conservation. thyroid tissue can be removed to reduce
receptors. Next, we learn that the drug Therefore, if aldosterone levels are secretion of thyroid hormone to within the
prevents the synthesis of messenger reduced, less Na+ is reabsorbed and less normal range. In addition, the remaining
RNA. We can therefore predict that the water is conserved. This results in a thyroid tissue normally does not enlarge
hormone functions by diffusing across lower blood volume and thus low blood enough to produce more thyroid hormone,
the cell membrane and binding to an pressure. Aldosterone targets the Na+–K+ although there are exceptions. The
intracellular receptor. The response of pump, which if you recall from chapter 3, removal of the thyroid tissue does not
the intracellular receptor is to produce transports Na+ and K+ in opposite directions. remove the influence of the abnormal
new messenger RNA, which leads to So as Na+ reabsorption decreases due to antibodies on the tissues behind the eyes.
synthesis of new proteins (see chapter 3 for reduced aldosterone, we would expect Thus, in many cases the condition’s effect
a description of the role of messenger RNA elevated blood K+ levels due to the on the eyes is not improved.
in protein synthesis). The new proteins reduced secretion of K+. High blood K+
produce the cell’s response to the hormone. levels lead to altered nerve and muscle Chapter 11
3. Recall that GH targets cartilage in the function, which could be life threatening.
epiphyseal plate of long bones and 7. To answer this question, you must first 2. To answer this question, we need to first
stimulates cell division of the chondrocytes. realize that cortisone mimics the normal determine the effect carbon monoxide
While Mr. Hoops’ son is actively growing, adrenal cortex secretion, cortisol, and has on red blood cells. Recall from our
GH administration would cause him to can, therefore, provide negative feedback reading of the function of red blood cells
grow taller. However, there could also at the anterior pituitary. Cortisone and the description of hemoglobin that
be unwanted changes consistent with inhibits ACTH secretion from the carbon monoxide binds very readily to
acromegaly (oversecretion of GH). Other anterior pituitary. Second, it’s important hemoglobin and does not tend to unbind.
side effects such as abnormal joint formation to understand that ACTH is required to Therefore, carbon monoxide–bound
and diabetes mellitus are also possible. prevent atrophy of the adrenal cortex. In hemoglobin in red blood cells can no
4. Remember that hormones of the the absence of ACTH, the adrenal cortex longer transport O2. This essentially leads
hypothalamus and anterior pituitary shrinks and may never recover to produce to a decrease in blood O2 levels. We also
regulate thyroid hormones. TRH from the its normal secretions even if ACTH learned that low blood O2 levels stimulate
hypothalamus stimulates the secretion secretion increases again. red blood cell production by causing the
of TSH from the anterior pituitary. TSH 8. It’s important to understand that a release of erythropoietin, primarily by
travels to the thyroid to promote secretion large meal, high in carbohydrates, will the kidneys. Erythropoietin stimulates
of thyroid hormones. In response to the increase blood glucose as the nutrients are red blood cell production in the red bone
large amount of this protein that is similar transported from the small intestine into marrow. So, we can predict that the
to TSH, thyroid hormones are oversecreted the blood. The body cells need to take up number of red blood cells in the person’s
by the thyroid gland (hyperthyroidism). the glucose across their cell membranes blood will increase.
Because production of the protein cannot either to utilize it immediately or to store it
be inhibited by thyroid hormones as for later use. Cells take up glucose only in 3. Referring to table 11.2 will help identify
TSH is, oversecretion of thyroid gland is the presence of insulin. Glucose serves as each of the white blood cells. It is also
prolonged, and the symptoms associated the stimulus for insulin secretion and the helpful to compare the size of each
with hyperthyroidism become obvious. inhibitor of glucagon secretion. Thus, after cell to red blood cells as well. In each
Because TSH stimulates gland growth as eating, insulin levels increase and glucagon figure, red blood cells are visible for easy
well as hormone secretion, the thyroid levels decrease. Long before 12 hours has comparison. (a) The cell in this figure is
gland enlarges. In addition, the increased passed after a meal, blood glucose levels slightly larger than red blood cells and has
thyroid hormones have a negative-feedback drop. Again, it is glucose that serves as a large round nucleus with a small amount
effect on the hypothalamus and pituitary the signal for hormone secretion. Now of cytoplasm. This cell is a lymphocyte.
gland. TSH-releasing hormone secretion the reduction in blood glucose stimulates (b) The cell in this figure is larger than a
from the hypothalamus and TSH secretion glucagon secretion and inhibits insulin red blood cell and has many bluish-purple
from the anterior pituitary gland are inhibited. secretion. Glucagon then promotes release granules. This cell is a basophil. (c) The
5. Insufficient vitamin D results in of stored glucose into the blood to be cell in this figure is very large and has a
insufficient Ca2+ absorption by the utilized by cells until the next meal. kidney-shaped nucleus. It is a monocyte.
intestine. As a result, blood Ca2+ levels 9. The pineal gland secretes melatonin, (d) The cell in this figure has a three-lobed
begin to fall. In response to the low blood which inhibits the release of reproductive nucleus. It is most likely a neutrophil.
Ca2+ levels, PTH is secreted from the hormones by acting on the hypothalamus (e) The cell in this figure has a bi-lobed
parathyroid glands. PTH acts primarily of the brain. If the pineal gland secretes nucleus and many bright red–stained
on bone, causing bone to be broken less melatonin, it should no longer have granules. It is an eosinophil.
down and Ca2+ to be released into the an inhibitory effect on the hypothalamus.
blood to maintain blood Ca2+ levels As a result, reproductive hormones could 4. People with type AB blood were called
within the normal range. So much Ca2+ be secreted in greater amounts. If this universal recipients because they could
can eventually be removed from bones condition occurred in a child before receive types A, B, AB, or O blood with
that they become soft, fragile, bent or puberty, we would predict exaggerated little likelihood of a transfusion reaction.
deformed, and easily broken. In adults the development of the reproductive system. Looking at figure 11.11, you can see that
condition is called osteomalacia, and in The evidence for this mechanism is not as type AB blood does not have antibodies
children the condition is called rickets. clear in humans as it is in other animals. against A or B antigens. Transfusion of
6. Aldosterone is secreted by the adrenal 10. Removal of part of the thyroid gland these antigens in types A, B, AB, or
cortex under low blood pressure reduces the amount of thyroid hormone O blood therefore does not cause a
conditions and results in increased Na+ secreted by the gland. Usually, enough transfusion reaction in a person with
type AB blood. The term is misleading,
however, for two reasons. First, other
blood groups can cause a transfusion

A-24 Appendix E

reaction. Second, antibodies in the donor’s to the tissue, including the conducting A severely narrowed opening through
blood can cause a transfusion reaction. system tissue, in the area is reduced and the aortic semilunar valve increases the
For example, type O blood contains tissue function is reduced. The conduction amount of work the heart must do to
anti-A and anti-B antibodies that can of action potentials through that side pump the normal volume of blood into
react against the A and B antigens in of the heart is slowed or blocked. As a the aorta. A greater pressure is required
type AB blood. consequence, the left side of the heart in the ventricle to force the same amount
5. We learned that HDN is caused by an contracts more slowly and its pumping of blood through the narrowed opening
Rh incompatibility between a pregnant effectiveness is reduced. Since the right during ventricular contraction.
mother with Rh-negative blood and bundle branch is not affected, the right
her Rh-positive child. If the mother is side of the heart contracts more normally. 7. Recall that the first heart sound occurs
sensitized to the Rh antigen, she can 5. There are two different scenarios that at the beginning of ventricular systole
produce anti-Rh antibodies that cross we need to consider to answer this (contraction) and results from closure of
the placenta and cause agglutination and question. First, a person who has a the AV valves, and the second heart sound
hemolysis of fetal red blood cells. To damaged left bundle branch will exhibit occurs at the beginning of ventricular
treat HDN with an exchange transfusion, the consequences outlined for Predict diastole (relaxation) and results from
the donor’s blood should be Rh-negative, question 4, but we need to describe how closure of the semilunar valves. Most of
even though the newborn is Rh-positive. the electrocardiogram will also be altered. the ventricular contraction occurs between
Rh-negative red blood cells do not have We learned that the QRS complex results the first and second heart sounds of the
Rh antigens. Therefore, any anti-Rh from depolarization of the ventricles same beat. Between the first and second
antibodies in the newborn’s blood do after action potentials pass through the heart sounds, blood is ejected from the
not react with the transfused Rh-negative bundle branches to the Purkinje fibers. ventricles into the pulmonary trunk and
red blood cells. Eventually, all of the In this first scenario, action potentials the aorta. Between the second heart sound
Rh-negative red blood cells die, and only pass through the right bundle branch of one beat and the first heart sound of the
Rh-positive red blood cells are produced normally but conduction of action next beat, the ventricles are relaxing and
by the newborn. potentials through the left bundle branch is the semilunar valves are closed. No blood
6. After reading the question, we know to slowed because of the damage. As a result, passes from the ventricles into the aorta
focus on blood tests that are associated the QRS complex has an abnormal shape or pulmonary trunk during that period.
with identification of bacterial infections. and it is prolonged.
White blood cells defend the body against In the second scenario, many ectopic 8. The shhh sound made after a heart sound
pathogens. A white blood differential cell action potentials arise in the atria. Ectopic is created by the backward flow of blood
count would be useful and would show action potentials originate in areas other after closure of a leaky or incompetent
an abnormally high neutrophil percentage, than the SA node (the pacemaker of the valve. A swishing sound immediately after
as those cells are associated with bacterial heart). Each ectopic action potential the second heart sound (lubb-duppshhh)
infections. initiates a new heartbeat, so we can predict represents a leaky aortic semilunar or
that many ectopic action potentials cause pulmonary semilunar valve. The shhh
Chapter 12 an increase in heart rate. It is possible for sound before a heart sound is created by
some ectopic action potentials arising in blood being forced through a narrowed, or
2. After reviewing figure 12.11a, we can see the atria to occur while the ventricles are stenosed, valve just before the valve closes.
that the anterior interventricular artery depolarized, but these action potentials The lubb-shhhdupp suggests that there is
supplies blood to the anterior wall of the do not initiate ventricular contraction. a swishing sound immediately before the
heart and much of the left ventricle. A Therefore, there can be more P waves second heart sound, indicating a stenosed
blocked anterior interventricular artery than QRS complexes in the aortic or pulmonary semilunar valve.
reduces the O2 supply to the tissue and the electrocardiogram. If ectopic action
cardiac muscle in that area of the heart is potentials do not occur in a regular 9. In response to severe hemorrhage, blood
not able to contract effectively. fashion, they can cause the heart to beat pressure decreased, which is detected
at an irregular rate, or arrhythmically. by baroreceptors. The decreased blood
3. Before answering the question, we need 6. Before addressing the effects of a leaky pressure leads to a reduced frequency
to define tetanic contraction. Recall aortic semilunar valve on left ventricle of action potentials sent from the
from chapter 7 that a tetanic contraction blood volume, first review the blood baroreceptors to the medulla oblongata.
is a sustained contraction in which the flow under normal conditions. In a This causes the cardioregulatory center
frequency of stimulation of the muscle normal person, the aortic semilunar to increase sympathetic stimulation of
is so rapid that no relaxation occurs. The valve closes during ventricular relaxation. the heart and increase the heart rate.
purpose of cardiac muscle contractions At the same time, blood flows out of the Normally, sympathetic stimulation of the
is to pump blood through the circulation left atrium and into the left ventricle. heart also increases stroke volume, as long
by contracting and relaxing in a repeated When the aortic semilunar valve is leaky as the volume of blood returned to the
cycle. Tetanic contractions in cardiac (incompetent), some blood leaks back heart is optimizing ventricular stretching,
muscle would interrupt the pumping action into the left ventricles from the aorta or preload. Following hemorrhage,
produced by the cycle of contraction during ventricular relaxation. When this however, the blood volume in the body
and relaxation and the blood flow would blood is added to the blood that normally is reduced, and the venous return to the
cease. Tetanic skeletal muscle contractions enters the left ventricle from the left heart from the body is reduced. This
are important to maintain posture or to atrium, there is a greater than normal leads to a reduction in preload. According
hold a limb in a specific position. volume of blood in the left ventricle just to Starling’s law of the heart, as venous
before ventricular contraction. return and preload decrease, so does stroke
4. If the normal blood supply is reduced in volume. So, the heart rate is increased due
a small area of the heart through which to sympathetic stimulation, but the volume
the left bundle branch passes, O2 supply of blood returning to the heart is decreased;

Appendix E A-25

thus, the ventricle does not fill with blood. weak pulse. The second condition to include the baroreceptor reflexes,
As a consequence, the stroke volume is low consider is why would cardiovascular chemoreceptor reflexes, and hormonal
and the heart rate is high. shock due to hemorrhage cause a weak mechanisms. In response to a dramatic
10. Rupture of the left ventricle can occur pulse. Cardiovascular shock due to drop in blood pressure due to the
several days after a myocardial infarction. hemorrhage, or loss of large volumes of rapid loss of a large volume of blood,
As the necrotic tissues are being removed blood, will reduce the volume of blood the baroreceptor mechanism, adrenal
by macrophages, the wall of the ventricle returning to the heart. If this occurs, medullary mechanism, and chemoreceptor
becomes thinner and may bulge during the stroke volume will also be greatly mechanism increase the heart rate and
systole. If the wall of the ventricle becomes reduced since there is not as much blood result in vasoconstriction of blood
very thin before new connective tissue is to be pumped from the heart. Again, vessels, especially in the skin and viscera.
deposited, it can rupture. If the left ventricle the low stroke volume leads to a weak Angiotensin II is produced quickly; it
ruptures, blood flows from the left ventricle pulse. The third condition to consider causes vasoconstriction and stimulates
into the pericardial sac, resulting in cardiac is why exercise causes a stronger pulse. aldosterone secretion. Aldosterone,
tamponade. As blood fills the pericardial Exercise causes an increase in heart rate which requires up to 24 hours to become
sac, it compresses the ventricle from the and stroke volume. The increased stroke maximally active, increases water
outside. As a consequence, the ventricle is volume causes a stronger pulse. reabsorption from the kidneys and reduces
not able to fill with blood and its pumping 5. Recall from reading “Capillary Exchange” the loss of water in the form of urine.
ability is rapidly eliminated. Rupture of and reviewing figure 13.25 that blood Blood volume is therefore increased. All of
the left ventricular wall, therefore, quickly pressure in the capillaries causes outward these mechanisms increase blood pressure
results in death. movement of fluid out of the capillaries back to its normal value.
and osmotic pressure causes inward If blood is lost over several hours,
Chapter 13 movement of fluid into the capillaries. the decrease in blood pressure is not
(a) If the plasma protein concentration as dramatic as when blood loss occurs
2. As stated in the question, atherosclerosis in the blood is decreased, the osmotic quickly. Consequently, mechanisms that
of vessels occurs when lipid deposits pressure will decrease and there is less respond to a rapid and large decrease in
block the vessels, which results in movement of fluid from the tissues to blood pressure are stimulated to a lesser
reduced blood flow through the vessel. the capillaries, causing edema. (b) If degree. These include the chemoreceptor
The tissues to which the blocked vessels blood pressure within a capillary reflex, the vasopressin mechanism, and
supply blood will therefore have reduced increases, more fluid is forced out of the adrenal medullary mechanism. The
O2 and nutrients. Since the carotid artery the capillary into the peripheral tissue, baroreceptor reflexes are most sensitive to
supplies blood to the brain, we would causing edema. sudden decreases in blood pressure, but the
expect atherosclerosis of these vessels to 6. While the student was sitting with her baroreceptor reflexes are still sensitive to
lead to reduced brain function, which may legs crossed, the blood vessels, particularly decreases in blood pressure that occur over
include confusion and loss of memory. in the skin, were blocked. O2 and nutrient a period of several hours. The baroreceptor
levels decrease and waste products reflexes that trigger vasoconstriction in
3. To answer this question, let’s view accumulate in tissues supplied by the response to the blood loss are substantial.
figures 13.14 and 13.5 to see the direction blocked blood vessels. Recall that the The kidneys detect even small decreases
of blood flow and the arrangement of precapillary sphincters that regulate blood in blood volume. Consequently, the
vessels and parts of the heart. Also, flow through capillaries are regulated renin-angiotensin-aldosterone mechanism
remember that veins carry blood towards by metabolic needs, such as O2 and is activated and remains active until the
the heart. An embolus that formed in the nutrients. When these levels decrease, the blood pressure is returned to its normal
posterior tibial vein would pass through precapillary sphincters relax allowing more range of values. Aldosterone secretion
the popliteal vein, femoral vein, external blood flow through the tissues, and causing increases and, though it requires several
iliac vein, common iliac vein, and inferior the appearance of the red blotch in the area hours to become maximally active, it
vena cava. From the inferior vena cava, that previously lacked blood flow. continues to stimulate water reabsorption
the embolus would then pass through 7. Raynaud syndrome causes severe by the kidneys, increasing blood volume
the right atrium and right ventricle of the vasoconstriction in the fingers and until the blood pressure returns to its
heart before moving into the pulmonary toes. This means that blood flow to the normal range of values.
trunk. The embolus would then pass from fingers and toes is severely restricted.
the pulmonary trunk into either the right The restricted blood flow will alter the Chapter 14
or left pulmonary arteries into the smaller appearance and the health of the tissue
vessels of the lungs. The embolus would of the fingers and toes. Due to the lack of 2. The function of lymphatic vessels is to
most likely lodge in the lungs because blood flow, the fingers and toes appear return fluid from the peripheral tissues to
as it moved from the posterior tibial vein white. If blood flow is not sufficient to the circulation. If lymphatic vessels are cut
towards the heart, it was passing through provide O2 and nutrients to and remove and tied, the movement of the fluid would
larger and larger vessels. The vessels waste products from the tissues of the be interrupted and edema will occur.
of the lungs would be too small for the fingers and toes, cell damage and death
embolus to pass through. could occur. Necrotic (dead) tissue and 3. Review figure 14.11 to answer this
gangrene may develop. question. We learned that a B cell
4. The first condition to consider is why 8. The rapid loss of a large volume of blood phagocytizes and processes antigens
premature heartbeats result in a weak activates the mechanisms responsible for that combine with MHC molecules on
pulse. Premature beats of the heart maintaining blood pressure. Recall that the surface of the cell. Helper T cells
result in the heart contracting before blood pressure regulatory mechanisms interact with the MHC-antigen complex to
it has time to fill to its normal capacity. stimulate the B cell to divide. The daughter
The volume of blood ejected from the cells then produce antibodies. If the antigens
heart will therefore be less causing a

A-26 Appendix E

are eliminated, the stimulus for B cell the structure of the trachea ensures that the Therefore, the Po2 inside the cells declines,
proliferation and antibody production is air passageway remains open under most which increases the partial pressure
then removed. conditions due to the reinforcement by the difference for O2 across the cell membrane.
4. The first exposure to the disease-causing cartilage, but the trachea has the flexibility This results in increased movement of O2
agent (antigen) evokes a primary immune to allow the esophagus to expand and food into the cells. The aerobic production of
response, which destroys the existing to move towards the stomach. ATP also produces CO2 (see chapter 17).
pathogens but also produces memory 4. During respiratory movements, the Therefore the Pco2 inside the cell goes up.
cells that can respond to future infections. parietal and visceral pleurae slide over This increases the partial pressure difference
As time passes, the antibodies produced each other. Normally, the pleural fluid in for CO2 across the membrane causing
during the primary immune response the pleural cavities lubricates the surfaces increased movement of CO2 out of cells.
will degrade and memory cells will die. of these membranes. When the pleural 1 0. A rapid rate of breathing increases the
If, before all of the memory cells are membranes are inflamed, their surfaces blood pH because CO2 is eliminated
eliminated, a second exposure to the become roughened. The rough surfaces from the blood more quickly during rapid
antigen occurs, a secondary response rub against each other and create an respiration. As CO2 is lost, H+ and HCO3−
results, increasing the number of intense pain. The pain is increased when combine to form H2CO3, which in turn
antibodies and memory cells again. The a person takes a deep breath because the dissociates to form CO2 and H2O. The
newly produced memory cells could movement of the membranes is greater lowered H+ levels cause an increase in
provide immunity until the next exposure than during normal breaths. blood pH. Holding your breath results in a
to the antigen. 5. In order for us to inhale, our thoracic decrease in pH because CO2 accumulates
5. After reading the Systems Pathology, cavity must be able to expand, which in the blood. The CO2 combines with H2O
we learned that SLE is an autoimmune increases its volume. When the volume to form H2CO3, which dissociates to form
disorder in which self-antigens activate increases, the pressure is lowered allowing H+ and HCO3−. The elevation in H+ levels
immune responses. Often, this results air to flow into the lungs down its pressure causes a decrease in blood pH.
in the formation of immune complexes gradient. The diaphragm contracts 1 1. When a person breathes rapidly and
and inflammation. Sometimes antibodies downward onto the liver. By relaxing the deeply for several seconds, the CO2
bind to antigens on cell membranes, abdominal muscles, the liver and other levels decrease and blood pH increases.
resulting in the rupture of the cell abdominal organs also move downward Carbon dioxide is an important regulator
membranes. Purpura results from bleeding (inferiorly). This makes it easier for the of respiratory movements. A decrease in
into the skin. One cause of purpura diaphragm to move downward while blood CO2 and an increase in blood pH
is thrombocytopenia, a condition in expanding the thoracic cavity. reduce the stimulus to the respiratory
which the number of platelets is greatly 6. The tube should apply suction. In order center. As a consequence, respiratory
reduced, resulting in decreased platelet for the lung to expand, the pressure movements stop until blood CO2 levels
plug formation and blood clotting (see in the alveoli must be greater than the build up again in the body fluid. This
chapter 11). Considering that SLE is an pressure in the pleural cavity. This can be normally takes only a short time.
autoimmune disorder, we can predict accomplished by lowering the pressure 12. By viewing figure 15.13 and Appendix B
that the purpura is the result of the in the pleural cavity through suction. we see that normal blood Po2 levels are
production of antibodies that destroy Applying air under pressure would make 75–100 mm Hg and normal blood Pco2
platelets causing thrombocytopenia. the pressure in the pleural cavity greater levels are 35–43 mm Hg. A Po2 of 60
than the pressure in the alveoli, which mm Hg and a Pco2 of 30 mm Hg are both
Chapter 15 would keep the alveoli collapsed. below normal. Let’s first focus on how
7. The resting person with a tidal volume Will’s Po2 could be low. The movement of
2. Another way to word this question would of 500 mL and breathing rate of air into and out of the lungs is restricted
be, “What is the function of the nasal 12 respirations/min has a minute ventilation because of the asthma, and there is a
passageway?” We learned that the nasal of 6000 mL (500 mL × 12 respirations/ mismatch between ventilation of the
passageway warms and humidifies the min). The exercising person with a tidal alveoli and blood flow to the alveoli.
air. Therefore, breathing with your mouth volume of 4000 mL and a breathing Consequently, because of the ineffective
open brings in drier than normal air, which rate of 24 respirations/min has a ventilation, blood O2 levels decrease.
irritates the throat and trachea. Running in minute ventilation of 96,000 mL Will’s hyperventilating also explains why
cold weather with your mouth open results (4000 mL × 24 respirations/min). The his Pco2 is low. As Will hyperventilates
in the same scenario. Cold air is dry, and difference between the two is 90,000 mL to help maintain blood O2 levels it also
breathing through the mouth doesn’t allow more air per minute than the person at rest. results in lower than normal blood CO2
for humidification of the air. 8. The main principle allowing for acquisition levels. (If there were no hyperventilation,
of O2 and removal of CO2 are pressure we would expect decreased blood O2 but
3. We learned that the cartilage rings of the differences. Therefore, inadequate increased blood CO2.)
trachea are incomplete, C-shaped rings, ventilation causes a smaller difference in
and that the esophagus lies in the groove the Po2 and Pco2 across the respiratory Chapter 16
of those rings along the posterior side membrane. Therefore, the rate of O2
of the trachea. When a large mouthful and CO2 diffusion across the membrane 2. Four. Recall that the greater omentum is
of food is swallowed, it will stretch the decreases, causing O2 levels in the blood a localized mesentery, which consists of
esophagus in the area through which the to decrease and CO2 levels to increase. serous membranes. Each single layer of
food passes. Because the posterior region 9. During exercise, skeletal muscle cells the mesentery has two layers of simple
of the trachea is flexible, as the region of increase O2 use in order to produce the ATP squamous epithelium. Since the greater
the esophagus expands, the adjacent area molecules required for muscle contraction. omentum is folded back on itself, that results
of the trachea momentarily collapes as the in 4 layers of simple squamous epithelium.
food passes. This is advantageous because

Appendix E A-27

3. First, it is important to define the function its function is lost. If the vitamins were 8. When blood vessels constrict, the flow of
of a normal palate. Normally, during broken down by digestion before being warm blood to the skin is reduced and the
swallowing, the soft palate is elevated, absorbed, they would not be functional temperature of the skin is also reduced.
closing off the nasopharynx so that liquids and vitamin deficiencies would occur. The benefit is that less heat is lost through
and food bypass the nasal cavity and enter 3. To answer this question we need to first the skin to the environment and the
the esophagus. A cleft in the soft palate identify the Daily Value for carbohydrates, internal body temperature is maintained.
would result in food and liquid entering which is 300 g/day. The % Daily Value is As the difference in temperature between
the nasal cavity during swallowing. If a then determined by dividing the amount the skin and the environment decreases,
person laughs suddenly while drinking in the serving of food (30 g) by the Daily less heat is lost. If the skin temperature
a liquid, the liquid may be explosively Value (300 g). The % Daily Value for decreases too much, however, dilation of
expelled from the mouth and even the carbohydrates from one serving of this food blood vessels to the skin occurs, which
nose. If a person tries to swallow and product is 10% (30/300 = 0.10, or 10%). prevents the skin from becoming so cold
speak at the same time, choking is most 4. Recall that the % Daily Values for that it is damaged.
likely to occur. Speaking requires that the energy-producing nutrients are based
epiglottis be elevated, so that air can pass on a 2000 kcal/day diet. We can use the Chapter 18
out of the larynx. When the epiglottis is % Daily Values of a food on the Nutrition
raised, food or liquid could pass into the Facts food label to determine how the 2. First, recall that the afferent arteriole
larynx and choke the person. amounts of certain nutrients in the food fit supplies the glomerulus with blood to be
into the overall diet. If a person consumes filtered. The afferent arteriole has a larger
4. First, let’s consider that acidic chyme 1800 kcal/day, the % Daily Values will be diameter than the efferent arteriole. This
in the small intestine is the stimulus. reduced proportionally. To calculate the means that blood enters the glomerulus
Stimuli are detected by receptors and then adjusted % Daily Values, the actual caloric at a faster rate than it exits, which causes
control centers send a signal to initiate a intake (1800 kcal/day) should be divided blood in the glomerular capillaries to be
response that will regulate homeostasis. by 2000 kcal/day. On a 1800 kcal/day diet, under higher pressure than other capillary
In this case, the control center is the the total percentage of Daily Values for beds in the body. The high pressure in the
pancreas. In response to the acidic chyme, energy-producing nutrients should add glomerular capillaries is the driving force
pancreatic secretin stimulates bicarbonate up to no more than 90% because of filtration in the renal corpuscle. Thus,
ion secretion from the pancreas (the 1800/2000 = 0.9, or 90%. by changing the glomerular capillary
effector), which neutralizes the acidic 5. The last step in the electron-transport pressure, the rate of filtration can be
chyme. Thus, secretin prevents the acid chain is when the electrons are passed to changed. Second, remember that arteriolar
levels in the chyme from becoming too O2 to form water. If this step is blocked, walls have a layer of smooth muscle and
high, and keeps them in the normal range. the citric acid and electron-transport can vasoconstrict. If the afferent arteriole
The neutralization of the acidic chyme chain cannot function, so ATP will not were to constrict, its diameter would
removes the stimulus for more secretin be produced aerobically. Lactic acid be reduced, which would reduce the
release and bicarbonate ion is no longer fermentation alone cannot produce volume of blood entering the glomerulus.
secreted. Because the response was sufficient levels of ATP to maintain normal Reducing the volume of blood in the
inhibited, this is an example of a negative- cellular activity and death will occur. glomerulus reduces the pressure. Since more
feedback system. 6. We can see from table 17.1 that one cola pressure equals more filtration, it follows
or beer has about 145 kcal/serving. To that less pressure equals less filtration and
5. An enema is introduction of fluid into the determine the time it takes to burn these therefore reduced urine production.
rectum, which causes it to distend. Recall kilocalories we divide the kcal/serving by
that the defecation reflex is initiated by the number of kilocalories used per hour. 3. First, remember that urine formation is
the movement of feces into the rectum and Watching TV uses 95 kcal/h, so 145/95 is greatly influenced by osmosis. The ability
the subsequent stretch of the rectal wall. equal to about 1.5 hours, or 1 hour and of the kidney to produce concentrated
Therefore, because an enema stretches the 30 minutes. Jogging at a pace of 6 mph urine by reabsorbing water depends on the
rectal wall, it initiates the defecation reflex. uses 580 kcal/h, so 145/580 is equal to standing salt gradient. If the concentration
0.25 hours, or 15 minutes. of salt or other compounds, such as
6. Recall that diarrhea is either increased 7. Recall that catabolism of food releases glucose, in the urine exceeds that of the
stool frequency or increased stool energy that can be used by the body for medullary interstitial fluid, the kidney
volume, which can result in the abnormal normal biological work, such as muscle won’t be able to reabsorb the water from
loss of fluid and ions from the colon. contraction. However, about 40% of the the urine. The glucose molecules attract
This fluid loss from the colon affects total energy released is actually used for water and, because the glucose molecules
the cardiovascular system in the same biological work. The remaining energy is are trapped in the nephron, the amount
way that blood loss does. In either case, lost as heat. Exercise increases the amount of water that remains in the nephron is
the result is hypovolemia, which causes of biological work and therefore requires increased. Urine volume will therefore be
a drop in blood pressure in a positive- more energy in the form of ATP. As more much higher. In addition, because glucose
feedback cycle. Eventually heart failure ATP is produced to fuel the exercise, cannot be reabsorbed by the kidney, the
results from insufficient blood flow to the more heat is also generated as lost energy, urine concentration will be greater than
heart itself. thereby increasing body temperature. a healthy person’s.
Shivering consists of small, rapid muscle
Chapter 17 contractions that produce heat in an effort 4. Reabsorption of water from the nephron
to prevent a decrease in body temperature is based on osmosis. If Na+ and Cl−
2. Most of the vitamins, with the exception in the cold. are not actively transported out of the
of A, D, and niacin, are essential vitamins, nephron, the concentration of ions inside
meaning they cannot be produced by the the nephron stays elevated. The normal
body but must be obtained from the diet. osmotic gradient that moves water out
Recall that after a vitamin is destroyed,

A-28 Appendix E

of the nephron is greatly reduced and However, the kidney also plays an level after ovulation and prevents further
the water stays in the nephron, which important role in the regulation of blood development of follicles. Therefore,
increases urine volume. pH. The kidney’s rate of H+ secretion administration of a large amount of
5. Because the solution was a saline solution, into the urine and reabsorption of HCO3− progesterone and estrogen just before the
it had the same concentration of solutes as increase. This helps prevent high blood preovulatory LH surge inhibits the release
the body fluids. Therefore, the excess IV H+ levels and low blood pH in Adam. of GnRH, LH, and FSH. Consequently,
solution did not change the concentration ovulation does not occur. However,
of the body fluids, but it did increase 9. After 7 days Roger’s kidneys began progesterone is the more potent hormone
the volume of body fluids. An increased to produce a large volume of urine when it comes to inhibiting ovulation.
volume of saline solution increases with larger than normal Na+ and Injections of a small amount of estrogen
the blood volume and blood pressure. K+ concentrations. As a result, just before ovulation could stimulate
Increased blood pressure stimulates Roger became dehydrated by day GnRH, LH, and FSH secretion with little
baroreceptors, which results in inhibition 9. Dehydration results in reduced negative effect on ovulation.
of ADH secretion. Remember that ADH blood volume and blood pressure. His 5. Molly’s mother could have had
normally conserves water. The reduced hematocrit was increased because the leiomyomas also, although, without direct
ADH secretion causes the kidneys to volume of his blood was decreased, but data from medical examinations, one
produce a large volume of urine. At the there was no decrease in the number of cannot be certain. If that was the cause
same time, the increased blood volume red blood cells. The percentage of the of her irregular menstruations, they may
stretches the walls of the atria, especially blood made of red blood cells therefore have become less frequent as Molly’s
the right atrium, and causes the release increased. The pale skin was the result mother experienced menopause. During
of atrial natriuretic hormone. Atrial of vasoconstriction, which was triggered menopause, the uterus gradually becomes
natriuretic hormone acts on the kidneys by the reduced blood pressure. Dizziness smaller, and eventually the cyclical
to reduce Na+ reabsorption. Because Na+ resulted from reduced blood flow to changes in the endometrial lining cease.
reabsorption is decreased, both Na+ and the brain when Roger tried to stand and If the condition was relatively mild, the
water are lost in the urine. The increased walk. He was lethargic in part because of onset of menopause could explain the
pressure also results in less renin secretion reduced blood volume, but also because gradual disappearance of the irregular
from the kidney. The reduced renin causes of low blood levels of K+ and Na+, caused and prolonged menstruations. (Note: If
less angiotensinogen to be converted by the loss of these ions in the urine. the tumors are large, constant and severe
to angiotensin. Consequently, less Low blood levels of Na+ and K+ alter the menstruations are likely even if regular
angiotensin II is formed, which reduces electrical activity of nerve and muscle menstrual cycles stop due to menopause.)
aldosterone secretion from the adrenal cells and result in muscular weakness.
cortex. The decreased aldosterone slows The arrhythmia of his heart was due to Chapter 20
Na+ and water reabsorption, causing more low blood levels of K+ and increased
Na+ and water to be lost in the urine. sympathetic stimulation, which was also 2. To determine the days of the menstrual
Consequently, the urine volume and the triggered by low blood pressure. cycle when fertilization is most likely to
amount of NaCl in the urine increase until occur, we need to remember the timing
the excess saline solution is eliminated. Chapter 19 of ovulation, when the secondary oocyte
6. Recall that the female urethra is much is released from the ovary and available
shorter than the male urethra and is more 2. Recall that the prostate is inferior to for fertilization. Recall that ovulation
accessible to bacteria from the external the bladder and anterior to the rectum. usually occurs around day 14 post-LMP.
environment. For this reason, females are Physicians can manually palpate the Also recall that sperm cells remain viable
more susceptible to bladder infections prostate through the wall of the rectum. in the female reproductive tract for up to
than males. The patient is fully awake and has 6 days and that the secondary oocyte is
7. Remember that acidic pH is due to an relatively minor discomfort. capable of being fertilized for up to 1 day
elevated concentration of H+. Hydrogen after ovulation. Considering all of these
ions in the blood are derived from the 3. To answer the question, you must first factors, we can conclude that fertilization
combination of CO2 and water. When remember that the testes are the major would occur if sexual intercourse occurred
someone is hyperventilating, the faster source of the hormone testosterone. between 5 days before ovulation and 1
breathing rate results in a greater than Secondary sexual characteristics, day following ovulation. That will be
normal rate of CO2 loss from the circulatory external genitalia, and sexual behavior between 10 days and 15 days post-LMP.
system. Because CO2 levels decrease, fewer development are all driven by You may find it interesting that data
H+ are formed and the pH becomes more testosterone. Therefore, an inability of indicate that the most fertile period during
basic. Breathing into a paper bag corrects the testes to produce normal amounts of the menstrual cycle is between 2 days just
for the effects of hyperventilation because the hormone would result in the failure before ovulation and the day of ovulation.
the person rebreathes air that has a higher to develop into a sexually mature male.
concentration of CO2. Carbon dioxide It is most likely that this individual’s 3. The primitive streak essentially forms the
levels increase in the body, more H+ are external genitalia would retain a juvenile central axis of an embryo. If two primitive
formed and pH levels drop back into the appearance and normal adult sexual streaks formed in one embryonic disk,
normal range. behavior would not develop. we would expect two different embryos,
8. Elevated blood CO2 levels cause an or essentially twins, to develop. If the
increase in H+ and a decrease in blood pH 4. The question has addressed the time two primitive streaks were touching each
due to the following reaction: period in the menstrual cycle just before other, conjoined twins would develop. The
the LH surge, which promotes ovulation. degree to which the two primitive streaks
CO2 + H2O H2CO3 H+ + HCO3− Referring to figure 19.14, it is evident that are touching would determine the severity
estrogen and progesterone are normally of the attachment.
at their lowest levels before the LH surge.
In contrast, progesterone is at its highest

Appendix E A-29

4. Recall that clinical age is dependent 5. Suckling causes a reflex release of 7. Since we assume that the nondisjunction
oxytocin from the mother’s posterior causing her Turner syndrome occurred in
on LMP (last menstrual period) of the pituitary. Oxytocin causes expulsion of the father, the girl would have inherited
milk from the breast, but it also causes her single X chromosome from her
mother and developmental age begins at contraction of the uterus. Contraction of mother. Hemophilia is an X-linked gene.
the uterus is responsible for the sensation If her mother is a carrier (XHXh) for
fertilization, which is assumed to occur of cramps in her abdomen. hemophilia, then there is a 50% chance
that she will pass the X chromosome with
on day 14 after LMP. Most of the times 6. Genotypes are the alleles a person has the recessive gene (Xh) to this daughter
for a given trait, and the phenotype is and a 50% chance that she will pass the
reported in the text are developmental the person’s appearance. In the case of X chromosome with the normal gene (XH)
polydactyly, there are three possible to this daughter. So, we can conclude that
age. To determine the clinical age, genotypes: DD (homozygous dominant), there is a 50% chance that a female with
Dd (heterozygous), and dd (homozygous Turner syndrome, who inherited her only
add 14 to the developmental age. The recessive). Since polydactyly is a X chromosome from her mother (a carrier
dominant trait, we would expect the of hemophilia), would have hemophilia.
one exception is parturition, which is individuals with genotypes DD or Dd to
exhibit polydactyly and the individuals
reported as clinical age. To determine the with the genotype dd not to exhibit
polydactyly.
developmental age, subtract 14 from the

clinical age. We can easily construct a

table to compare the ages:

Clinical Developmental

Age Age

Fertilization 14 days 0 days

Implantation 21 days 7 days

Fetal period begins 70 days 56 days

Parturition 280 days 266 days

Glossary

Many of the words in this glossary and acetabulum (as-ĕ-tab′ū-lŭm) [L., shallow resemble two minute strands of pearls
throughout the text are followed by a simplified vinegar vessel or cup] Cup-shaped twisted together.
phonetic spelling showing pronunciation. The depression on the lateral surface of the coxal action potential All-or-none change in
pronunciation key reflects standard clinical bone, where the head of the femur articulates. membrane potential in an excitable tissue
usage, with minor modifications, as presented that is propagated as an electrical signal.
in Stedman’s Medical Dictionary (27th edition), acetylcholine (as-e-til-kō′lēn) Neurotransmitter activation energy Energy that must be
which has long been a leading reference substance released from motor neurons added to atoms or molecules to start a
volume in the health sciences. that innervate skeletal muscle fibers, all chemical reaction.
autonomic eganglionic neurons, all active transport Carrier-mediated process
ā as in day, ate, way postganglionic parasympathetic neurons, that requires ATP and can move substances
a as in mat, hat, act some postganglionic sympathetic neurons, into or out of cells from a lower to a higher
ă as in alone, abortion, media and some central nervous system neurons. concentration.
ah as in father adaptive immunity Immune system response
ar as in far acetylcholinesterase (as′e-til-kō-lin-es′ter-ās) in which there is an ability to recognize,
aw as in fall (fawl) Enzyme that breaks down acetylcholine to remember, and destroy a specific antigen.
ē as in be, bee, meet acetic acid and choline. adduction (ă-dŭk′shŭn) [L. adductus, to bring
ĕ as in taken, genesis toward] Movement toward the midline.
er as in term, earn, learn acetyl-CoA (as′e-til) Acetyl-coenzyme A; adductor (a-dŭk′ter, -tōr) [L. adductus, to
ı̄ as in pie, pine, side formed by the combination of the two- bring toward] Muscle causing movement
i as in pit, tip, fit carbon acetyl group with coenzyme A; the toward the midline.
ı̆ as in pencil molecule that combines with a four-carbon adenoid (ad′ĕ-noyd) Enlarged pharyngeal
ō as in no, note, toe molecule to enter the citric acid cycle. tonsil.
o as in not, box, cot adenosine triphosphate (ă-den′ō-sēn trı̄-
ŏ as in occult, lemon, son Achilles (ă-kil′ēz) tendon Common tendon fos′fāt) (ATP) Adenosine, an organic base,
oo as in food, to, tool of the calf muscles that attaches to the heel with three phosphate groups attached to
ow as in cow, brow, plow, now (calcaneus); named after a mythical Greek it; energy stored in adenosine triphosphate
oy as in boy, toy, oil warrior who was vulnerable only in the heel. is used in nearly all the energy-requiring
u as in wood, foot, took reactions in the body.
ŭ as in but, sun, bud, cup, up acid (as′id) Any substance that is a proton ADH See antidiuretic hormone.
ū as in pure, unit, union, future donor; or any substance that releases adipose (ad′i-pōs) [L. adeps, fat] Fat; relating
hydrogen ions. to fat tissue.
abdomen (ab-dō′men, ab′dō-men) Belly, adrenal cortex (ă-drē′năl kōr′teks) The outer
between the thorax and the pelvis. acidic solution Solution with more hydrogen part of the adrenal gland, which secretes the
ions than hydroxide ions; has a pH of less following steroid hormones: glucocorticoids,
abdominal cavity (ab-dom′i-năl) Space than 7. mainly cortisol; mineralocorticoids, mainly
bounded by the diaphragm, the abdominal aldosterone; and androgens.
wall, and the pelvis. acidosis (as-i-dō′sis) Condition characterized adrenal gland (ă-drē′năl) [L. ad, to; ren,
by a lower than normal blood pH (pH of kidney, near or on the kidneys] One of two
abdominopelvic cavity (ab-dom′i-nō- 7.35 or lower). endocrine glands located on the superior
pel′vik) Abdominal and pelvic cavities pole of each kidney; secretes the hormones
considered together. acinus (as′i-nŭs), pl. acini (as′i-nı̄) [L., berry, epinephrine, norepinephrine, aldosterone,
grape] Grape-shaped secretory portion cortisol, and androgens.
abduction (ab-dŭk′shun) [abductio] of a gland. adrenal medulla (ă-drē′năl me-dool′ă) Inner
Movement away from the midline. part of the adrenal gland, which secretes
acromegaly (ak-rō-meg′ă-lē) [G. acro; megas, mainly epinephrine but also small amounts
absorption (ab-sōrp′shŭn) The taking in or large] Disorder marked by progressive of norepinephrine.
reception of gases, liquids, light, heat, or enlargement of the bones of the head,
solutes, such as the movement of digested face, hands, feet, and thorax as a result of adrenaline (ă-dren′ă-lin) [from the adrenal
molecules across the intestinal wall and into excessive secretion of growth hormone by gland] Synonym for epinephrine.
the bloodstream; the movement of substances the anterior pituitary gland.
through the skin; and the movement of fluid adrenocorticotropic hormone (ă-drē′nō-
into the lymphatics from the interstitial fluid. acromion (ă-krō′mē-on) [Fr. akron, tip + omos, kōr′ti-kō-trō′pik) [L. ad, near + ren, kidney
shoulder] Lateral end of the spine of the + cortico, cortex + trophre, nurture]
accommodation (ă-kom′ŏ-dā′shŭn) The act or scapula that projects as a broad, flattened (ACTH) Hormone of the anterior pituitary
state of adjustment or adaptation, such as the process overhanging the glenoid fossa; gland that stimulates the adrenal cortex to
increase in the thickness and convexity of the articulates with the clavicle. secrete cortisol.
lens of the eye in order to focus an object on
the retina as the object moves closer to the acrosome (ak′rō-sōm) [acro, tip + G. soma,
eyes; decreasing sensitivity of a nerve cell to body]. A caplike organelle surrounding the
a stimulus of constant strength. anterior portion of a sperm cell, containing
enzymes that facilitate entry of the sperm
G-1 cell through the zona pellucida.

actin myofilament (ak′tin mı̄-ō-fil′ă-ment)
One of the two major kinds of protein fibers
that make up a sarcomere; thin filaments;

Glossary G-2

adventitia (ad-ven-tish′ ă) [L. adventicius, amylase (am′ il-ās)  One of a group of anterior (an-tēr′ ē-ōr) [L., to go before]  That
coming from abroad or outside; foreign] starch-splitting enzymes that cleave starch, which goes first; in humans, toward the
Outermost covering of an organ that glycogen, and related polysaccharides. belly or front.
is continuous with the surrounding
connective tissue. anabolism (ă-nab′ ō-lizm) [G. anabole, a anterior horn  Part of the spinal cord gray
raising up] All the synthesis reactions that matter containing motor neurons; also
aerobic respiration (ār-ō′ bik) Breakdown occur within the body; requires energy. called the ventral horn or motor horn.
of glucose in the presence of oxygen
to produce carbon dioxide, water, and anaerobic respiration (an-ār-ō′ bik) anterior pituitary gland  Portion of the pituitary
approximately 38 ATP molecules; includes Breakdown of glucose in the absence of gland derived from the oral epithelium.
glycolysis, the citric acid cycle, and the oxygen to produce lactic acid and two ATP
electron-transport chain. molecules; consists of glycolysis and the antibody (an′ tē-bod-ē) [G. anti, against +
reduction of pyruvic acid to lactic acid. body, a thing]  Protein in the plasma that is
afferent (af′ er-ent) [L. afferens, to bring to] responsible for antibody-mediated (humoral)
Inflowing; conducting toward a center, anaphase (an′ ă-fāz) [G. ana, up + phases, immunity; binds specifically to an antigen.
denoting certain arteries, veins, lymphatics, appearance] Stage of mitosis or meiosis
and sensory nerves. Opposite of efferent. in which the chromosomes move from the antibody-mediated immunity Immunity
center area of the cell, the equatorial plane, resulting from B cells and the production
afferent arteriole (ar-tēr′ ē-ōl)  Small artery toward the poles of the cell. of antibodies.
in the renal cortex that supplies blood to
the glomerulus. anatomical position (an′ ă-tom′ i-kăl)  anticoagulant (an′ tē-kō-ag′ ū-lant) Chemical
Position in which a person is standing that prevents coagulation or blood clotting;
afferent fiber  Sensory nerve fiber going from erect with the feet facing forward, the arms an example is antithrombin.
the peripheral to the central nervous system; hanging to the sides, and the palms of the
sensory or afferent fiber. hands facing forward. antidiuretic hormone (an′ tē-dı̄-ū-ret′ ik)
[G. anti, against + uresis, urine volume]
afterload  Resistance against which the anatomy (ă-nat′ ŏ-mē) [G. ana, apart + tome, (ADH) Hormone secreted from the
ventricles must pump blood; it is increased a cutting]  Scientific discipline that posterior pituitary gland that acts on the
in people who have hypertension. investigates the structure of the body. kidney to reduce the output of urine; also
called vasopressin.
agglutination (ă-gloo′ ti-nā′ shŭn) [L. ad, androgen (an′ drō-jen) [G. andros, male]
to + gluten, glue]  Process by which cells Hormone that stimulates the development antigen (an′ ti-jen) [G. anti (body) + -gen, a
stick together to form clumps. of male sexual characteristics; includes thing]  Substance that induces a state of
testosterone. sensitivity or resistance to microorganisms
agonist (ăg′ ōn-ist) [G. agon, a contest] or toxic substances after a latent period;
Denoting a muscle in a state of contraction, anemia (ă-nē′ mē-ă) [G. an, without + haima, substance that stimulates the adaptive
with reference to its opposing muscle, or blood]  Condition that results in less than immune system; self-antigens are produced
antagonist. normal hemoglobin in the blood or a lower by the body, and foreign antigens are
than normal number of red blood cells. introduced into the body.
agranulocyte (ă-gran′ ū-lō-sı̄t) [G. a-, without
+ granular + kytos, cell]  White blood anencephaly (an′ en-sef′ ă-lē) Defective antigen receptor  Molecule on the surface of
cell with very small cytoplasmic granules development of the brain with absence of lymphocytes that specifically binds antigens.
that cannot be easily seen with the light the cerebral and cerebellar hemispheres and
microscope; lymphocytes and monocytes. with only a rudimentary brainstem. aorta (ā-ōr′ tă) [G. aorte, from + aeiro, to lift
up] Large, elastic artery that is the main trunk
aldosterone (al-dos′ ter-ōn)  Steroid hormone angina pectoris (an′ ji-nă pek′ tō-ris, an-jı̄′ nă) of the systemic arterial system, which carries
produced by the adrenal cortex that facilitates Pain resulting from a reduced blood supply blood from the left ventricle of the heart and
potassium exchange for sodium in the to cardiac muscle. passes through the thorax and abdomen.
distal convoluted tubule and collecting
duct, causing sodium ion reabsorption and angioplasty (an′ jē-ō-plas-tē) [G. angio, aortic semilunar valve  Semilunar valve
potassium and hydrogen ion secretion. blood vessel]  Technique used to dilate consisting of three cusps of tissue located
the coronary arteries by threading a at the base of the aorta where it arises from
alkaline solution (al′ kă-lı̄n) See basic solution. small, balloonlike device into a partially the left ventricle; the cusps overlap during
alkalosis (al-kă-lō′ sis) Condition blocked coronary artery and then inflating ventricular diastole to prevent leakage of
the balloon to enlarge the diameter of blood from the aorta into the left ventricle.
characterized by a higher than normal blood the vessel.
pH (pH of 7.45 or above). apex (ā′ peks) [L., tip]  Extremity of a conical
alveolar duct (al-vē′ ō-lăr)  Part of the respiratory angiotensin (an-jē-ō-ten′ sin) [angio, blood or pyramidal structure; the apex of the heart
passages beyond a respiratory bronchiole; vessel + tensus, to stretch]  Angiotensin I is the rounded tip directed anteriorly and
from it arise alveolar sacs and alveoli. is a peptide derived when renin acts on slightly inferiorly.
alveolar sac  Two or more alveoli that share a angiotensinogen; angiotensin II is formed
common opening. from angiotensin I when angiotensin- aphasia (ă-fā′ zē-ă) [G. a-, without + phasis,
alveolus (al-vē′ ō-lŭs), pl. alveoli (al-vē′ ō-lı̄) converting enzyme acts on angiotensin I; speech or speechlessness]  Impaired or absent
[L., small cavity or hollow sac]  Cavity; angiotensin II is a potent vasoconstrictor, communication by speech, writing, or signs
examples include the sockets into and it stimulates the secretion of because of dysfunction of brain centers in the
which the teeth fit and the ends of the aldosterone from the adrenal cortex. dominant cerebral hemisphere.
respiratory system.
amino acid (ă-mē′ nō)  Class of organic acids angiotensinogen (an′ jē-ō-ten-sin′ ō-jen) apocrine (ap′ ō-krin) [G. apo, away from
containing an amine group (NH2) that Protein found in the blood that gives rise + krino, to separate]  Type of gland
makes up the building blocks of proteins. to angiotensin I after renin, an enzyme whose cells contribute cytoplasm to its
amniotic cavity (am-nē-ot′ ik) [G. amnios, secreted from the kidney, acts on it. secretion; sweat glands that produce organic
lamb] Fluid-filled cavity surrounding and secretions traditionally are called apocrine;
protecting the developing embryo. ANH See atrial natriuretic hormone. however, these sweat glands are now known
to be merocrine glands; see also merocrine
antagonist (an-tag′ ŏ-nist)  Muscle that works and holocrine.
in opposition to another muscle.

G-3 Glossary

aponeurosis (ap′ ō-noo-rō′ sis) [G. neuron, atherosclerosis (ath′ er-ō-skler-ō′ sis) autocrine (aw′ tō-krin) [G. autos, self + krino,
sinew; end of a muscle where it becomes a [G. athere, gruel or soft, pasty material to separate]  Denoting self-stimulation
tendon]  Sheet of fibrous connective tissue, + sklerosis, hardness]  Lipid deposits through cellular production of a factor
or an expanded tendon, serving as the origin (plaques) in the tunica intima of large and a specific receptor for it.
or insertion of a flat muscle. and medium-sized arteries.
autoimmune disease (aw-tō-i-mūn′ ) Disorder
appendicular (ap′ en-dik′ ū-lăr) [L. appendo, atom (at′ ŏm) [G. atomos, indivisible, uncut] resulting from a specific immune system
to hang something on]  Relating to an Smallest particle into which an element reaction against self-antigens.
appendage, such as the limbs and their can be divided using chemical methods;
associated girdles. composed of neutrons, protons, and electrons. autonomic nervous system (ANS) (aw-tō-
nom′ ik)  Part of the peripheral nervous
appendix (ă-pen′ diks), pl. appendices (ă- atomic number (ă-tom′ ik)  Number of protons system composed of efferent fibers that
pen′ di-sēs) [L. appendo, to hang something in an element. reach from the central nervous system to
on] Smaller structure usually attached by smooth muscle, cardiac muscle, and glands.
one end to a larger structure; a small blind ATP See adenosine triphosphate.
extension of the colon attached to the autosome (aw′ tō-sōm) [G. auto-, self + soma,
cecum. atrial natriuretic (ā′ trē-ăl nā′ tre-yū-ret′ ik) body]  Any chromosome other than a sex
hormone (ANH)  Hormone released from chromosome; normally occurs in pairs in
appositional growth (ap-ō-zish′ ŭn-ăl) [L. cells in the atrial wall of the heart when somatic cells and singly in gametes.
ap + pono, to place at or to]  To place one atrial blood pressure is increased; lowers
layer of bone, cartilage, or other connective blood pressure by increasing the rate of AV See atrioventricular.
tissue against an existing layer; increases urine production. axial (ak′ sē-ăl) [L. axle, axis]  Head, neck, and
the width or diameter of bones.
atrioventricular (AV) bundle (ā-trē-ō-ven- trunk as distinguished from the extremities.
aqueous humor (ak′ wē-ŭs, ā′ kwē-ŭs) Watery, trik′ ū-lar)  Bundle of modified cardiac axon (ak′ son) [G., axis]  Main process of a
clear fluid that fills the anterior chamber muscle fibers that projects from the AV
and posterior chamber of the eye. node through the interventricular septum; neuron; usually conducts action potentials
conducts action potentials from the AV node away from the neuron cell body.
arachnoid mater (ă-rak′ noyd ma′ ter) [G. rapidly through the interventricular septum;
arachne, spiderlike, cobweb]  Thin, also called the bundle of His. baroreceptor (bar′ ō-rē-sep′ ter) [G. baro,
cobweblike meningeal layer surrounding weight or pressure]  Sensory nerve endings
the brain and spinal cord; the middle of atrioventricular (AV) node  Small collection in the walls of the atria of the heart, aortic
three layers. of specialized cardiac muscle fibers located arch, and carotid sinuses; sensitive to
in the inferior part of the right atrium; stretching of the wall caused by increased
areola (ă-rē′ ō-lă), pl. areolae (ă-rē′ ō-lē) delays action potential transmission to blood pressure; also called a pressoreceptor.
[small areas]  Pigmented area surrounding the atrioventricular bundle.
the nipple of a mammary gland. baroreceptor reflex  Process in which
atrioventricular valve  Valve between the atrium baroreceptors detect changes in blood
areolar (ă-rē′ ō-lăr)  Relating to connective and the ventricle of the heart, the tricuspid pressure and produce changes in heart rate,
tissue with small spaces within it; loose valve between the right atrium and right force of heart contraction, and blood vessel
connective tissue. ventricle, and the bicuspid (or mitral valve) diameter that return blood pressure toward
between the left atrium and left ventricle. normal levels.
arrector pili (ă-rek′ tōr pı̄′ lı̄) [L., that which
raises hair]  Smooth muscle attached to the atrium (ā′ trē-ŭm), pl. atria (ā′ trē-ă) basal nuclei  Nuclei at the base of the
hair follicle and dermis that raises the hair [L., entrance chamber]  One of the two cerebrum, diencephalon, and midbrain
when it contracts. chambers of the heart that collect blood involved in controlling motor functions.
during ventricular contraction and pump
arteriosclerosis (ar-tēr′ ē-ō-skler-ō′ sis) blood into the ventricles to complete base  Any substance that is a proton acceptor
[L. arterio- + G. sklerosis, hardness]  ventricular filling at the end of ventricular or any substance that binds to hydrogen
Hardness of the arteries. relaxation; the right atrium receives blood ions; lower part or bottom of a structure;
from the inferior and superior venae cavae the base of the heart is the flat portion
arteriosclerotic lesion (ar-tēr′ ē-ō-skler-ot′ ik) and from the coronary sinus and delivers directed posteriorly and superiorly; veins
Lesion or growth in arteries that narrows the blood to the right ventricle; the left atrium and arteries project into and out of the
lumen, or passage, and makes the walls of receives blood from the pulmonary veins base, respectively.
the arteries less elastic. and delivers blood to the left ventricle.
basement membrane  Structure that
artery (ar′ ter-ē) [G. arteria, the windpipe] Blood auditory (aw′ di-tōr-ē)  Relating to hearing. attaches most epithelia (exceptions
vessel that carries blood away from the heart. auditory ossicles (os′ i-klz)  Bones of the include lymphatic vessels and the liver
sinusoids) to underlying tissue; consists
articulation (ar-tik-ū-lā′ shŭn) [L. articulatio, middle ear; the malleus, incus, and stapes. of carbohydrates and proteins secreted
a forming of vines]  Place where two bones by the epithelia and the underlying
come together; a joint. auditory tube  Air-filled passageway between connective tissue.
the middle ear and pharynx.
artificial heart  Mechanical pump used to basic solution (bā′ sik)  Solution with fewer
replace a diseased heart. auricle (aw′ r ı̆-kl) [L. auris, ear]  Fleshy part hydrogen ions than hydroxide ions; has a
of the external ear on the outside of the pH greater than 7.
artificial pacemaker  Electronic device head; a small, conical pouch projecting
implanted beneath the skin with an from the upper anterior part of each atrium basilar membrane (bas′ i-lăr)  One of two
electrode that extends to the heart; provides of the heart. membranes forming the cochlear duct;
periodic electrical stimuli to the heart and supports the spiral organ.
substitutes for a faulty SA node. auscultatory (aws-kŭl′ tă-tō-rē) [L. ausculto,
to listen]  To listen to the sounds made by basophil (bā′ sō-fil) [G. basis, base + phileo,
astrocyte (as′ trō-sı̄t) [G. astron, star + kytos, the various body structures, especially to love]  White blood cell with granules
a hollow cell]  Star-shaped neuroglial to Korotkoff sounds when determining that stain purple with basic dyes; promotes
cell that helps regulate the composition blood pressure. inflammation and prevents clot formation.
of fluid around the neurons of the central
nervous system.

Glossary G-4

belly  Largest part of a muscle between the Bowman’s capsule  Enlarged end of the required to raise the temperature of
origin and insertion. nephron; Bowman’s capsule and the 1000 grams of water from 14°C to 15°C.
glomerulus make up the renal corpuscle.
benign (bē-nı̄n′ ) [L. benignus, kind]  Mild in calyx (kā′ liks), pl. calyces (kal′ i-sēz) [G.,
character or nonmalignant; does not spread brachialis (brā′ kē-ăl-is)  Muscle of the anterior flower petal or cup of a flower]  Small
to distant sites. arm that originates on the humerus and container into which urine flows as it
inserts onto the ulna; flexes the forearm. leaves the collecting ducts at the tip of the
beta-adrenergic (bā′ tă ad-rĕ-ner′ jik) blocking renal pyramids; the calyces come together
agent  Drug that binds to and prevents brachial plexus (brā′ kē-ăl) [L. brachium, arm] to form the renal pelvis.
adrenergic receptors from responding to Nerve plexus to the upper limb; originates
adrenergic compounds that normally bind to from spinal nerves C5 to T1. canaliculus (kan-ă-lik′ ū-lŭs)  Tiny canal in bone
beta-adrenergic receptors and cause them to between osteocytes containing osteocyte
function; beta-adrenergic blocking agents are brainstem  Portion of the brain consisting of cell processes; a cleftlike lumen between
used to treat certain arrhythmias in the heart the midbrain, pons, and medulla oblongata. the cells of each hepatic cord, connects
and to treat tachycardia (rapid heart rate). medial corner of the eye to the lacrimal sac.
breathing (brēthing)  Movement of air into
biceps brachii (bı̄′ seps brā′ kē-ı̄)  Muscle in the and out of the lung; see ventilation. cancer (kan′ ser) [L., a crab, suggesting
anterior arm with two heads, or origins, on crablike movement]  Malignant neoplasm,
the scapula and an insertion onto the radius; bronchiole (brong′ kē-ōl)  One of the finer or tumor.
flexes and supinates the forearm. subdivisions of the bronchial tubes, less
than 1 mm in diameter, that has no cartilage capacitation (kă-pas′ i-tā′ shŭn) Process
bicuspid valve (bı̄-kŭs′ pid)  Valve closing the in its wall but has relatively more smooth whereby the sperm cells develop the ability
opening between the left atrium and left muscle and elastic fibers than do larger to fertilize oocytes.
ventricle of the heart; has two cusps; also bronchial tubes.
called the mitral valve. capillary (kap′ i-lār-ē) [L. capillaris, relating to
bronchus (brong′ kŭs), pl. bronchi (brong′ kı̄) hair, resembling a fine hair]  Minute blood
bile (bı̄l)  Fluid secreted from the liver, [G. bronchos, windpipe]  Any one of the air vessel consisting only of simple squamous
stored in the gallbladder, and released ducts conducting air from the trachea to the epithelium and a basement membrane;
into the duodenum; consists of bile salts, bronchioles. major site for the exchange of substances
bile pigments, bicarbonate ions, fats, and between the blood and tissues.
other materials. buccinator (buk′ s ı̆-nā′ tōr)  Muscle making up
the lateral sides of the oral cavity; flattens carbohydrate (kar-bō-hı̄′ drāt) Organic
bile salt  Organic salt secreted by the liver that the cheeks. molecule made up of one or more
emulsifies lipids. monosaccharides chemically bound
buffer (bŭf′ er)  Chemical that resists changes together; sugars and starches.
bilirubin (bil-i-roo′ bin) [L., bile + ruber, red] in pH when either an acid or a base is added
Bile pigment formed from the heme in to a solution containing the buffer. carbonic anhydrase (kar-bon′ ik an-hı̄′ drās)
hemoglobin during the destruction of red Enzyme that increases the rate at which
blood cells by macrophages. bundle of His See atrioventricular bundle. carbon dioxide reacts with water to form
burn  Lesion caused by heat, acid, or other hydrogen ions and bicarbonate ions.
biopsy (bı̄′ op-sē)  Process of removing
tissue from living patients for diagnostic agents; a partial-thickness burn of the carcinoma (kar-si-nō′ mă) [G. karkinoma,
examination, or a specimen obtained by skin damages only the epidermis (first- cancer + oma, tumor]  Malignant tumor
biopsy. degree burn) or the epidermis and part of derived from epithelial tissue.
the dermis (second-degree burn); a full-
blastocele (blas′ tō-sēl) [G. blastos, germ + thickness (third-degree) burn destroys the cardiac cycle (kar′ dē-ak)  One complete
koilos, hollow]  Cavity in the blastocyst. epidermis and the dermis and sometimes the sequence of cardiac systole and diastole.
underlying tissue.
blastocyst (blas′ tō-sist) [G. blastos, germ + bursa (ber′ să) [L., purse or pocket]  Closed sac cardiac output  Volume of blood pumped by
kystis, bladder]  Early stage of mammalian or pocket containing synovial fluid; usually either ventricle of the heart per minute;
embryo development consisting of a hollow found in areas where friction occurs. about 5 L/min for the heart of a healthy
ball of cells with an inner cell mass and an adult at rest.
outer trophoblast layer. calcaneus (kal-kā′ nē-ŭs) [L., the
heel]  Largest tarsal bone forming the heel. cardioregulatory center  Specialized area
blood-brain barrier  Cellular and matrix within the medulla oblongata of the
barrier made up primarily of blood vessel calcitonin (kal-si-tō′ nin)  Hormone, released brain that receives sensory input and
endothelium, with some help from the from cells of the thyroid gland, that acts on controls parasympathetic and sympathetic
surrounding astrocytes; it allows some tissues, especially bone, to cause a decrease stimulation of the heart.
(usually small) substances to pass from the in blood levels of calcium ions.
circulation into the brain but does not allow carotene (kar′ ō-tēn)  Yellow pigment in plants
other (larger) substances to pass. calcium channel blocker (kal′ sē-ŭm) Class such as squash and carrots; accumulates in
of drugs that specifically block channels in the lipids of the stratum corneum and in the
blood group  Category of red blood cells based cell membranes through which calcium ions fat cells of the dermis and hypodermis and is
on the type of antigen on the surface of the pass; calcium channel blockers are used to used as a source of vitamin A.
red blood cell; for example, the ABO blood treat some kinds of cardiac arrhythmias.
group is involved with transfusion reactions. carotid bodies (ka-rot′ id)  Small organs near
callus (kal′ ŭs) [L., hard skin]  Thickening of the carotid sinuses that detect changes in
blood pressure [L. pressus, to press]  The force the stratum corneum of skin in response to blood oxygen, carbon dioxide, and pH.
blood exerts against the blood vessel walls; friction; the zone of tissue repair between
expressed relative to atmospheric pressure fragments of a broken bone. carotid sinus  Enlargement of the internal
and reported in the form of millimeters of carotid artery near the point where the
mercury (mm Hg) of pressure. calorie (kal′ ō-rē) [L. calor, heat]  Unit of heat internal carotid artery branches from
or energy content; the quantity of energy the common carotid artery; contains
bony labyrinth (lab′ i-rinth) Interconnecting required to raise the temperature of 1 gram baroreceptors.
tunnels and chambers within the temporal of water 1°C. A Calorie (Cal), or kilocalorie
bone in which the inner ear is located. (kcal), is the amount of heat or energy carpal (kar′ păl) [G. karpos, wrist]  Associated
with the wrist; bones of the wrist.

G-5 Glossary

carrier molecule  Protein that extends from cervical plexus  Nerve plexus of the neck; chyle (kı̄l) [G. chylos, juice]  Milky colored
one side of the cell membrane to the other; originates from spinal nerves C1–C4. lymph with a high fat content.
binds to molecules to be transported and
moves them from one side of the membrane cervix (ser′ viks) [L., neck]  Lower part of the chylomicron (kı̄-lō-mi′ kron) [chylo- +
to the other. uterus extending to the vagina. G. micros, small]  Lipid droplet synthesized
in the epithelial cells of the small intestine
cartilage (kar′ ti-lij) [L. cartilage, gristle]  chemical (kem′ i-kăl)  Relating to chemistry, containing triglycerides, cholesterol, and
Firm, smooth, resilient, nonvascular especially to the characteristics of atoms lipoproteins.
connective tissue. and molecules and to their interactions.
chyme (kı̄m) [G. chymos, juice]  Semifluid
cascade (kas-kād′ ) [Fr. cascare, to fall]  Series chemical bond  Association between two mass of partly digested food passed from
of sequential interactions, which once atoms formed when the outermost electrons the stomach into the duodenum.
initiated continues to the final one; each are transferred or shared between atoms.
interaction is activated by the preceding ciliary body (sil′ ē-ar-ē) [like an eyelash]
one, with cumulative effect. chemical mediator of inflammation Chemical Structure continuous with the choroid
released or activated by injured tissues and layer of the eye at its anterior margin
catabolism (kă-tab′ ō-lizm) [G. katabole, adjacent blood vessels; produces vasodilation, that contains smooth muscle cells and
a casting down]  All the decomposition increases vascular permeability, and attracts is attached to the lens by suspensory
reactions that occur in the body; releases blood cells; includes histamine, kinins, ligaments; regulates the thickness of the
energy. prostaglandins, and leukotrienes. lens and produces aqueous humor.

catalyst (kat′ ă-list)  Substance that increases chemical reaction  Process by which atoms cilium  (sil′ ē-ŭm), pl. cilia (sil′ ē-ă) [L., eyelid]
the rate of a chemical reaction; in the or molecules interact to form or break Mobile extension of a cell surface; varies
process, the catalyst is not permanently chemical bonds. from one to thousands per cell and contains
changed or used up. specialized microtubules enclosed by the
chemistry (kem′ is-trē) [G. chemeia, alchemy] cell membrane.
cecum (sē′ kŭm) [L. caecus, blind]  Blind sac Science dealing with the atomic composition
forming the beginning of the large intestine. of substances and the reactions they undergo. citric acid cycle (sit′ rik)  Series of chemical
reactions in which citric acid (six-carbon
cell  (sel) [L. cella, chamber]  Basic living unit chemoreceptor reflex (kem′ ō-rē-sep′ tŏr) molecule) is converted into a four-carbon
of all plants and animals. Process in which chemoreceptors detect molecule, carbon dioxide is formed, and
changes in oxygen levels, carbon dioxide energy is released; the released energy is
cell-mediated immunity  Immunity resulting levels, and pH in the blood and produce used to form ATP; the four-carbon molecule
from the actions of T cells. changes in heart rate, force of heart can combine with acetyl-CoA (two-carbon)
contraction, and blood vessel diameter that to form citric acid and start the cycle again.
cell membrane  Plasma membrane; outermost return these values toward their normal levels.
component of the cell, surrounding and clavicle (klav′ i-kl) [L., a small key]  Bone
binding the rest of the cell contents. cholecystokinin (kō′ lē-sis-tō-kı̄′ nin) [G. chole, between the sternum and shoulder; the
bile + kysis, bladder + kineo, to move] collarbone.
central canal  Small canal containing blood Hormone released from the duodenum;
vessels, nerves, and loose connective tissue inhibits gastric acid secretion and stimulates climacteric (klı̄-mak′ ter-ik, klı̄-mak-ter′ ik) [G.,
and running parallel to the long axis of a contraction of the gallbladder. the rung of a ladder]  Period of endocrine,
bone; also called a haversian canal. somatic, and transitory psychological
chondrocyte (kon′ drō-sı̄t) [G. chondrion, changes occurring in the transition to
central nervous system (CNS)  Brain and gristle + cyte]  Cartilage cell. menopause.
spinal cord.
chordae tendineae (kōr′ dē ten′ di-nē-ē) clitoris (klit′ ō-ris)  Small, erectile structure
centriole (sen′ trē-ōl)  Small organelle that [L., cord]  Tendinous strands running from located in the anterior margin of the vestibule.
divides and migrates to each pole of the the papillary muscles to the free margin of
nucleus; spindle fibers extend from the the cusps that make up the tricuspid and clot  (klot)  To coagulate; a soft, insoluble mass
centromeres to the centrioles during mitosis. bicuspid valves; prevent the cusps of these formed when blood coagulates.
valves from extending up into the atria
centromere (sen′ trō-mēr) [G. kentron, during ventricular contraction. clot retraction  Condensation of the clot into a
center + meros, part]  Specialized region denser, more compact structure.
where chromatids are linked together in choroid (kō′ royd) [G. chorioeides,
a chromosome. membranelike or lacy]  Portion of the clotting factor  One of many proteins found in
vascular tunic associated with the sclera the blood in an inactive state; activated in
cerebellum (ser-e-bel′ ŭm) [L., little brain] of the eye; prevents scattering of light. a series of chemical reactions that result in
Part of the brain attached to the brainstem; the formation of a blood clot.
important in maintaining muscle tone, choroid plexus  Specialized group of
balance, and coordination of movements. ependymal cells in the ventricles; secretes coagulation (kō-ag-ū-lā′ shŭn)  Process of
cerebrospinal fluid. changing from a liquid to a solid, especially
cerebral aqueduct (ser′ ĕ-brăl, sĕ-rē′ brăl)  blood.
Small connecting tube through the midbrain chromatid (krō′ mă-tid) [G. chroma, color]
between the third and fourth ventricles. One of a pair of duplicated chromosomes, cochlea (kok′ lē-ă)  Portion of the inner ear
joined by the centromere, which separates involved in hearing; shaped like a snail shell.
cerebrospinal fluid (ser′ ĕ-brō-spı̄-năl, sĕ-rē′ brō- from its partner during cell division.
spı̄-năl) (CSF)  Fluid filling the ventricles codon (kō′ don)  Sequence of three nucleotides
and surrounding the brain and spinal cord. chromatin (krō′ ma-tin) [G. chroma, color] in mRNA that codes for a specific amino
Genetic material of the nucleus consisting acid in a protein.
cerebrum (ser′ ĕ-brŭm, sĕ-rē′ brŭm) [L., brain] of deoxyribonucleic acid (DNA) associated
Largest part of the brain, consisting of two with proteins. coenzyme (kō-en′ zı̄m)  Substance that
hemispheres and including the cortex, nerve enhances or is necessary for the function
tracts, and basal nuclei. chromosome (krō′ mō-sōm) [G. chroma, color of an enzyme.
+ soma, body]  One of the bodies (normally
cerumen (sĕ-roo′ men) [L. cera, wax]  Specific 46 in humans) in the cell nucleus that carry collagen (kol′ lă-jen) [G. koila, glue +
type of sebum produced in the external the cell’s genetic information. gen, producing]  Ropelike protein of the
auditory canal; earwax. extracellular matrix.

cervical (ser′ v ı̆-kal) Neck.

Glossary G-6

collecting duct  Straight tubule that extends coronal plane (kōr′ ō-năl) [G. korone, crown] cryptorchidism (krip-tōr′ ki-dizm)  Failure of
from the cortex of the kidney to the tip of Plane separating the body into anterior and the testes to descend into the scrotal sac.
the renal pyramid; filtrate from the distal posterior portions; also called a frontal plane.
convoluted tubules enters the collecting cupula (koo′ poo-lă) [L. cupa, a tub]
duct and is carried to the calyces. coronary artery (kōr′ o-nār-ē) [circling like Gelatinous mass that overlies the hair cells
a crown]  Artery that carries blood to the of the cristae ampullaris of the semicircular
colliculus (ko-lik′ ū-lŭs) [L. collis, hill]  One muscles of the heart; the left and right canals; responds to fluid movement.
of four small mounds on the dorsal side of coronary arteries arise from the aorta.
the midbrain; the superior two are involved cutaneous (kū-tā′ nē-ŭs) [L. cutis, skin]
in visual reflexes, and the inferior two are coronary bypass  Surgery in which a vein Relating to the skin.
involved in hearing. from another part of the body is grafted
to a coronary artery in such a way as to cuticle (kū′ ti-kl) [L. cutis, skin]  Outer thin
colon (kō′ lon)  Division of the large intestine allow blood flow past a blockage in the layer, usually horny; for example, the
that extends from the cecum to the rectum. coronary artery. outer covering of hair or the growth of
the stratum corneum onto the nail.
commissure (kom′ ı̆-shūr) [L., a joining coronary vein  Vein that carries blood from the
together]  Bundle of nerve fibers passing heart muscle, primarily to the right atrium. cyanosis (sı̄-ă-nō′ sis) [G., dark blue color]
from one side to the other in the brain or Blue coloration of the skin and mucous
spinal cord. corpus callosum (kōr′ pus kă-lō′ sŭm) membranes caused by insufficient
[L., body; callous]  Large, thick nerve fiber oxygenation of blood.
common bile duct  Duct formed by the union tract connecting the two cerebral hemispheres.
of the common hepatic and cystic ducts; it cystic duct (sis′ tik)  Duct from the
joins the pancreatic duct and empties into corpus luteum (loo′ tē′ ŭm)  Yellow endocrine gallbladder; it joins the common hepatic
the duodenum. body formed in the ovary in the site of a duct to form the common bile duct.
ruptured follicle immediately after ovulation;
common hepatic duct  Duct formed by secretes progesterone and estrogen. cytoplasm (sı̄′ tō-plazm) [G. cyto, cell +
union of the right and left hepatic ducts; plasma, a thing formed]  Cellular material
it joins the cystic duct to form the common cortex (kōr′ teks), pl. cortices (kōr′ ti-sēz) surrounding the nucleus.
bile duct. [L., bark]  Outer part of an organ such as
the brain, kidney, adrenal gland, or hair. cytoskeleton (sı̄-tō-skel′ ĕ-ton) Collection
compact bone  Bone that is denser and has of microtubules, microfilaments, and
fewer spaces than spongy bone. cortisol (kōr′ ti-sol)  Steroid hormone released intermediate filaments that supports the
by the adrenal cortex; increases blood cytoplasm and organelles; also involved
complement (kom′ plĕ-ment)  Group of glucose and inhibits inflammation; it is with cell movements.
serum proteins that stimulate phagocytosis, a glucocorticoid.
inflammation, and lysis of cells. dartos muscle (dar′ tōs) [Fr. dero¯, to skin]
cotransport (kō-trans′ pōrt)  Transport of one Layer of smooth muscle beneath the skin
compound (kom′ pound) [to place together] substance across a cell membrane, coupled of the scrotum.
Substance containing two or more different with the simultaneous transport of another
kinds of atoms that are chemically combined. substance across the same membrane in the deciduous teeth (dē-sid′ ū-ŭs) [L. deciduus,
same direction. falling off]  Primary teeth, which fall out
concha (kon′ kă) [L., shell]  Structure to be replaced by the permanent teeth.
resembling a shell in shape; the three bony covalent bond (kō-vāl′ ent)  Chemical bond
ridges on the lateral wall of the nasal cavity. formed when two atoms share one or more decomposition reaction (dē′ kom-pō-zish′ ŭn)
pairs of electrons. Breakdown of a larger molecule into
condyle (kon′ dı̄l) [G. kondyles, knuckle] smaller molecules, ions, or atoms.
Rounded, articulating surface of a joint. coxal (kok′ săl) bone [L., hip]  Bone of the hip.
cranial nerve (krā′ nē-ăl)  Peripheral nerve deep [O.E. deop, deep]  Away from the
cone  Photoreceptor cell in the retina of the eye surface, internal.
with cone-shaped photoreceptive process; originating in the brain.
important in color vision and visual acuity. defecation (def-ĕ-kā′ shŭn) [L. defaeco, to
cranial vault  Eight skull bones that surround purify]  Discharge of feces from the rectum.
conjunctiva (kon-jŭnk-tı̄′ vă) [L. conjungo, to and protect the brain; braincase.
bind together]  Mucous membrane covering deglutition (dē-gloo-tish′ ŭn) [L. de-, from,
the anterior surface of the eye and the inner cremaster muscle (krē-mas′ ter) Extension away + glutio, to swallow]  Swallowing.
lining of the eyelids. of abdominal muscles; in the male, it raises
the testis. deltoid (del′ toyd) [triangular]  Triangular
connective tissue  One of the four major tissue muscle over the shoulder; inserts onto the
types; consists of cells usually surrounded crenation (krē-nā′ shŭn) [L. crena, a notch] humerus; abducts the arm.
by large amounts of extracellular material; Cell shrinkage that occurs when water
holds other tissues together and provides a moves by osmosis from a cell into a denaturation (dē-na-tū-rā′ shŭn) Change
supporting framework for the body. hypertonic solution. in shape of a protein caused by breaking
hydrogen bonds; agents that cause
constant region  Part of an antibody that does cretinism (krē′ tin-izm)  Hypothyroidism in an denaturation include heat and changes in pH.
not combine with an antigen and is the infant; appears during the first years of life
same in different antibodies; responsible and results in stunting of body growth and dendrite (den′ drı̄t) [G. dendrite, tree]  Short,
for activating complement and binding the mental development; hypothyroid dwarfism. treelike cell process of a neuron; receives
antibody to cells such as macrophages, stimuli.
basophils, and mast cells. cricoid cartilage (krı̄′ koyd)  Most inferior
laryngeal cartilage. dentin (den′ tin)  Bonelike material forming
corn [L. cornu, horn]  Thickening of the the mass of a tooth.
stratum corneum of the skin over a bony cricothyrotomy (krı̄′ kō-thı̄-rot′ ō-mē) Formation
projection in response to friction or pressure. of an artificial opening in a victim’s air deoxyribonucleic (dē-oks′ ē-rı̄′ bō-noo-klē′ ic)
passageway through the membrane between acid (DNA) Type of nucleic acid containing
cornea (kōr′ nē-ă) [hornlike]  Transparent, the cricoid and thyroid cartilage. the sugar deoxyribose; the genetic material
anterior part of the fibrous tunic of the eye, of cells.
through which light enters the eye. crown  Part of the tooth formed of and covered
by enamel. depolarize  Decrease in the difference in
corneum (kōr′ nē-ŭm) See stratum corneum. potential (charge) between two points,
crypt  (kript) [G. kryptos, hidden]  Pitlike as between the inside and outside of a
depression. cell membrane.

G-7 Glossary

dermis (der′ mis) [G. derma, skin]  Dense together; glucose and fructose chemically efferent fiber  Nerve fiber going from
connective tissue that forms the deep layer join to form sucrose. the central nervous system toward the
of the skin; responsible for the structural dissociate (di-sō-sē-āt′ ) [L. dis- + socio, to peripheral nervous system; motor fiber.
strength of the skin. disjoin, separate]  Separation of positive and
negative ions when they dissolve in water ejaculation (ē-jak′ ū-lā′ shŭn) [to shoot out]
desmosome (dez′ mō-sōm) [G. desmos, a band and are surrounded by water molecules. Reflexive expulsion of semen from the penis.
+ soma, body]  Point of adhesion between distal (dis′ tăl) [L. di- + sto, to be distant]
two cells. Farther from the point of attachment to ejaculatory duct (ē-jak′ ū-lă-tōr-ē) Duct
the body than another structure. formed by the union of the ductus deferens
diabetes mellitus (dı̄-ă-bē′ tēz me-lı̄′ tŭs) distal convoluted tubule  Convoluted tubule of and the excretory duct of the seminal
Condition resulting from too little insulin the nephron that extends from the ascending vesicle, which opens into the urethra.
secreted from the pancreatic islets, limb of the loop of Henle and ends in a
insufficient numbers of insulin receptors collecting duct. electrocardiogram (ē-lek-trō-kar′ dē-ō-gram)
on target cells, or defective receptors that DNA See deoxyribonucleic acid. (ECG)  Graphic record of the heart’s
do not respond to insulin. dominant (dom′ i-nant) [L. dominus, a master]  electrical currents obtained with an
In genetics, a gene that is expressed electronic recording instrument.
diaphragm (dı̄′ ă-fram) [a partition wall] phenotypically to the exclusion of a
Muscular separation between the thoracic contrasting recessive trait. electrolyte (ē-lek′ trō-lı̄t) [G. electro, + lytos,
and abdominal cavities; its contraction dorsal (dōr′ săl) [L. dorsum, back]  Back soluble]  Positive and negative ions that
results in inspiration. surface of the body; in humans, synonymous conduct electricity in solution.
with posterior.
diaphysis (dı̄-af′ i-sis) [G., growing between] dorsal root  Sensory root of a spinal nerve. electron (ē-lek′ tron)  Negatively charged
Shaft of a long bone. ductus arteriosus (dŭk′ tŭs ar-tēr′ ē-ō-sŭs) Short particle around the nucleus of an atom.
artery that extends from the pulmonary trunk
diastole (dı̄-as′ tō-lē) [G. diastole, dilation] to the aorta; in the fetus, blood flows through electron-transport chain  Series of energy-
Relaxation of the heart chambers, during the ductus arteriosus from the pulmonary transfer molecules in the inner mitochondrial
which they fill with blood; usually refers trunk into the aorta and bypasses the lungs. membrane; they receive energy and use it in
to ventricular relaxation. ductus deferens (dūk′ tŭs def′ er-enz)  the formation of ATP and water.
Duct of the testis, running from the
diastolic pressure  Minimum arterial epididymis to the ejaculatory duct; also element (el′ ĕ-ment) [L. elementum, a
blood pressure achieved during ventricular called the vas deferens. rudiment]  Simplest type of matter with
diastole. duodenum (doo-ō-dē′ nŭm, doo-od′ ĕ-nŭm) unique chemical properties.
[L. duodeni, 12]  First division of the small
diencephalon (dı̄-en-sef′ ă-lon) [G. dia, intestine; connects to the stomach. embolus (em′ bō-lŭs) [G. embolos, a plug]
through + enkephalos, brain]  Part of the dura mater (doo′ ră mā′ ter) [L., tough mother] Detached clot or other foreign body that
brain inferior to and nearly surrounded by Tough, fibrous membrane forming the occludes a blood vessel.
the cerebrum and connecting posteriorly outermost meningeal covering of the brain
and inferiorly to the brainstem. and spinal cord. embryo (em′ brē-ō) [Fr. en, in + bryo¯, to swell] 
In prenatal development, the developing
diffusion (di-fū′ zhŭn) [L. diffundo, to pour eardrum See tympanic membrane. human from the time of fertilization to
in different directions]  Tendency for eccrine (ek′ rin) [G. ek, out + krino, to separate]  approximately the end of the second month.
solute molecules to move from an area of
higher concentration to an area of lower Exocrine; refers to water-producing sweat emission (ē-mish′ ŭn) [L. emissio, to send out]
concentration in a solution; the product glands; see merocrine. Discharge; formation and accumulation of
of the constant random motion of all atoms, ECG See electrocardiogram. semen prior to ejaculation.
ions, or molecules in a solution. ectoderm (ek′ tō-derm)  Outermost of the three
germ layers of the embryo. emulsification (ē-mŭl′ si-fi-kā-shŭn) 
digestion (di-jes′ chŭn, dı̄-jes′ chŭn)  ectopic beat (ek-top′ ik)  Heartbeat that Dispersal of one liquid, or very small
Breakdown of carbohydrates, lipids, originates from an area of the heart other globules of the liquid, within another liquid.
proteins, and other large molecules to than the SA node.
their component parts. edema (e-dē′ mă) [G. oidema, a swelling] emulsify (ē-mŭl′ si-fı̄)  To form an emulsion,
Excessive accumulation of fluid, usually which is one liquid dispersed within
digestive tract (di-jes′ tiv, dı̄-jes′ tiv) Tract causing swelling. another liquid.
from the mouth to the anus, including the efferent (ef′ er-ent) [L. efferens, to bring out]
stomach and intestines, where food is taken Conducting outward from a given organ enamel (ē-nam′ ĕl)  Hard substance covering
in, broken down, and absorbed. or part, denoting certain arteries, veins, the exposed portion of a tooth.
lymphatics, and motor nerves. Opposite
digitalis (dij′ i-tal′ is) [L., relating to fingerlike of afferent. endocardium (en-dō-kar′ dē-ŭm) [G. endon,
flowers]  Steroid used in the treatment efferent arteriole (ar-tēr′ ē-ōl)  Vessel that within + kardia, heart]  Innermost layer
of heart diseases, such as heart failure; carries blood from the glomerulus to the of the heart, including endothelium and
increases the force of contraction of the peritubular capillaries. connective tissue.
heart; extracted from the foxglove plant efferent ductule (dŭk′ tool)  Small duct that
(Digitalis purpura). leads from the testis to the epididymis. endochondral (en-dō-kon′ drăl) [endo +
G. chondrion, gristle]  Growth of cartilage,
diploid (dip′ loyd)  Condition in which which is then replaced by bone.
there are 2 copies of each autosome and
2 sex chromosomes (46 total chromosomes endochondral ossification (en-dō-kon′ drăl os′ i-
in humans). fi-kā′ shŭn)  Bone formation within cartilage.

disaccharidase (dı̄-sak′ ă-rid-ās) Enzyme endocrine (en′ dō-krin) [endo + G. krino,
that breaks disaccharides down to to separate]  Ductless gland that secretes
monosaccharides; commonly found in the internally, usually into the circulatory system.
microvilli of the intestinal epithelium.
endocytosis (en′ dō-sı̄-tō′ sis) [endo +
disaccharide (dı̄-sak′ ă-rı̄d) [two sugars]  G. kytos, cell + -osis, condition]  Bulk
Two monosaccharides chemically bound uptake of material through the cell
membrane by taking it into a vesicle.

endoderm (en′ dō-derm) [endo + G. derma,
skin]  Innermost of the three germ layers of
the embryo.