How body works

248 249

brain sexual attraction 244 in lungs 114, 115 childhood 38, 220–21, 231
active areas 65 sight 84–85 renal 150, 151 chloride 146
alcohol, effects of 61 smell sense 97 in skin 30 choking 142
autism 246 sound processing 90–91 sphincters 125 chromosomes
automatic functions control speech 104–105 wound repair 174
62 speed 60 carbohydrates DNA molecules 16, 17
baby’s 218–19 structure/components 62–63 diabetes 200 heredity 210–11
bipolar disorder 243 superior autobiographical digestion 144, 145 meiosis 19
body position sense 10, 101 irritable bowel syndrome (IBS) mitosis 18
breathing feedback system memory 247 telomeres 224
112 suprachiasmatic nucleus (SCN) 165 X and Y 16, 23, 210–11
child’s 220–21 liver’s use 156 chyme 141, 142, 143, 144, 145
circadian clock 198 198 low-carbohydrate diet 161 ciliary muscles 80, 81
corpus callosum 64 synesthesia 247 microbial digestion 149 circadian clock 198
death 227 thought processing 63 requirement 138 circulatory system see blood
default mode network 65 touch sense 76–77 carbon dioxide 112, 115–17, vessels; heart
depression 243 water balance 152 120–21, 125 coccidiodes fungus 177
development 218–21 white matter 62 cardiovascular exercise 132 cochlea 88, 89, 91, 95
dreaming 236–37 brainstem 61, 62, 63, 68, 79, cardiovascular system see cochlear implants 95
emotion formation 239 227, 237 blood vessels; heart codons 21
energy supply 161 breastfeeding 219 carpal tunnel syndrome 70 colds 182–183
exercise benefits 135 breasts 214, 222 cataracts 87 collagen 32, 36, 41, 46, 49,
fasting benefits 163 breathing cecum 146, 147 139
fight or flight response 240–41 anaphylaxis 186 celiac disease 165 colon 144, 146–47, 148, 149,
gray matter 62 asthma 187 cell membrane 14, 15, 18, 139 165; see also intestines
hallucinations 247 at birth 217 cells color blindness 87
hemispheres 64, 76–77 during/after exercise 130–31, aging 224, 225 color consistancy 85
hormone production 238 bacterial 148 color vision 83
hunger/satisfaction sensing 132 cell membranes 14, 15, 18, 139 comas 227
140 fight or flight response 241 cellular respiration 116 communication
integrated senses 102–103 gas exchange 114–117 death 15 nonverbal 108–109
itch response 79 hay fever 187 diameter 15 verbal 104–105
ketone body use 161 mechanics 112–113 DNA damage, repair 26–27 complement proteins 168
learning 62, 230–31 pregnancy effects 214 DNA molecules 16 cones 82–83
memory 231–33, 247 bruises 126–127 function 14–15 connective tissue 13; see also
nerve cell activity 65 burns 47 gene expression 22–23 ligaments; tendons
nerve cell number 65 butterflies in the stomach 69 hormone receptors 192, 193 copper 157
nerve pathways 65 butyric acid 149 multiplication 18–19 cornea 25, 80, 86, 87
networks 65 number 14 corpus callosum 64
obsessive compulsive disorder C self markers 170–171 corpus luteum 207
(OCD) 242 signaling 15 cortisol 109, 196, 198, 199, 238,
pain, sensing 78, 79 caffeine 152, 235 structure/components 14–15 240, 241
phobias 242 calcitonin 190, 195 types 13 coughing 118–119, 183
post-traumatic stress disorder calcium 36, 50, 51, 162, 190, viral invasions 182 CPR (cardiopulmonary
(PTSD) 243 centrosomes 15 resuscitation) 129
pregnancy effects 214 192, 194–95 cerebellum 62, 63, 101, 237 cranium 37, 45
puberty effects 222 calories 159–63 cerebral cortex 62, 63, 101 cryptococcus fungus 177
reading faces 106 cancer 18, 27, 31, 180–81, 226 cerebrum 62, 63, 76 cupula 92
sensory input/action output canine teeth 42–43 cervix 205, 216–17 cytokines 174–75, 178, 181, 183
60–61 capillary networks chemotherapy drugs 27 cytoplasm 14, 15, 20–21, 24
chewing 41, 44–45, 140, 142 cytosine 16, 17
blood pressure 124
in broken bones 49
diameter 117
gas exchange 116, 117, 125

D diseases size 205 production 191
death from 226 elastin 32 sexual attraction 244
daily rhythms 198–199 from DNA mutations 18, 26, 27 elbows 37, 54, 55, 71 epithelial cells/tissue 13,
deafness 94–95 infectious diseases 176–77 electrocardiograms (ECGs) 168
death 226–27 vaccines 184–85 esophagus 12, 140, 141, 142–43,
deep vein thrombosis 126 see also infections 122–23 165
defibrillation 129 embryos 212–13 estrogen
dehydration 131, 152 dislocations 49, 70 emotions functions 192
deltoid muscle 59 dizziness 92–93 menstrual cycle 206–207
dendritic cells 168 DNA (deoxyribonucleic acid) basic 238 osteoporosis 50
deoxyhemoglobin 117 development 220 during pregnancy 214, 215
depression 243 bases 16, 17 in dreams 237 production 191, 192, 223
dermis 31, 32, 47, 74–75, chemotherapy drugs 27 facial expressions 107 excretory system 141, 146–47,
copying 20 formation 239 150–51
174–75 damage and repair 26–27 hormones 238–39 exercise
diabetes 200–201, 226 double helix 16–17 and music 91 aerobic respiration 130–31
dialysis 151 exchange and recombination problems/disorders 242–43 anaerobic respiration 131
diaphragm 112–13, 118–19 purpose 239 benefits 134–35
diarrheal diseases 226 19 sexual attraction 244–45 bone production 50
diets 161–63, 200 free radicals 224 and smells 97 cardiovascular 132
digestive system 10–11 functions 16 endocrine system 10–11 fat-burning 133, 163
gene expression 17, 22 adrenal glands 191, 193, 238, fitness level 134–35
action/relaxation 68–69 gene therapy 27 heart rate 133
beneficial microbes 148–49 mutations 26 240, 241 hormonal benefits 197
bile 141, 144, 145, 155, 157 replication and division 18 hypothalamus 140, 152, 190, hydration 131
bloating 149 transcription 20 intensity 133
chewing and swallowing dopamine 197, 238, 244 193, 222 lactic acid levels 130–31
double-jointed people 41 ovaries 191, 192, 223, 238 resistance training 133
142–43 Down syndrome 19 pancreas 140, 141, 144, 158, runner’s high 239
colon 144, 146–47, 148, 149, dreaming 234, 236–37 timing 163
159, 191, 200–201 VO2 max 134–35
165 E pituitary gland 152, 190, 193, warm up 58
enzymes 141, 142, 144–45 eyelashes 81, 139
esophagus 12, 140, 141, eardrum 88, 94 206, 207, 240, 241 eyelids 81
ears testes 191, 205, 223, 238 eyes
142–43, 165 thyroid gland 190, 195, 199 afterimages 83
flatulence 149 aging 95, 225 see also hormones aging 86, 87, 225
food passage hours 140–41 balance function 92–93, 100 energy astigmatism 86
gas production 149 damage and disorders 94–95 action/relaxation 68 balance function 93
hunger/satisfaction hormones hair cells 13 balance 158–59, 190 binocular vision 84
joints 41 cellular respiration 116 blindspots 82
140, 198 localizing sound 90–91 fatty acids 158–59 body position sense 100
intestines see intestines ringing 95 fight or flight response 241 building from nutrients 139
large intestine 141, 146–47; sound reception 88–89 glucose 156, 157, 158–59, 200 cataracts 87
structure/components 36, from microbial digestion 149 correction reflex 93
see also colon; intestines 88–89, 92–93 from nutrients 138, 139 damage and disorders
liver see liver eating 140, 142–43, 198; see sugar trap 160–61
mouth 140 also digestive system use during exercise 130–31, 135 86–87
nutrient absorption 145 eczema 186 epidermis 31, 32, 47, 74–75, farsightedness 86
problems 141, 164–165 eggs 13 174–75 fight or flight response 241
small intestine 141, 144–45; fertilization 205, 208–209 epiglottis 119, 142 focus 81
heredity 210–11 epinephrine
see also intestines menstrual cycle 206–207 anaphylaxis, treating 186
stomach 141, 143; see also production 19 circulation in blood 120
fight or flight response 193,
stomach
structure/components 142–47 238, 240, 241
vomiting 165
direction sense 92

250 251

glaucoma 87 cravings 214 glaucoma 87 sound processing 90–91
image capture 80 nutrient requirements 138–39 glucagon 159, 191, 193 sound reception 88–89
images, forming 82–83 processing see digestive glucose heart
light spots 82 arrhythmias 129
lubrication 81 system; eating balance 158–59 arteries 128
nearsightedness 86 unhealthy choices 196 conversion from lactic acid beating 122–23
protection 81 fractures 38, 48–49 blood circulation 122–23
pupil control 68–69 freckles 33 121 blood flow 121, 128
rods and cones 82–83 free radicals 224 conversion from lactose 164 cardiovascular exercise 132
structure/components 80 friendships 221 diabetes 200–201 cycle 122–23
vision tests 87 fungal infections 168, 177 fight or flight response 241 damage 128
see also sight fungi, friendly 172–73 glycemic index (GI) 163 defibrillation 129
funny bone 37, 70, 71 hormones regulating 191, 193, ECG recording 122–23
F exercise benefits 135
G 196 fetal growth and development
facial expressions 106, 107, 108, lifestyle impacts 196–97
109, 239 galactose 164 production in liver 68, 156, 212
gallbladder 144, 155, 157 hormone production 191
facial recognition 106 gastrin 191 157 problems 128–29, 226
fascicles 56 gastrointestinal tract 138, sugar trap 160–161 sinoatrial node/pacemaker
fasting 162–63 use during exercise 130, 131
fat 140–41; see also intestines; gluten 165 122, 123
stomach gluten intolerance 165 structure 122–23
burning 133, 163 glycemic index (GI) 163 tissue repair 25, 128
metabolism 15, 156 gene swapping 19 glycogen 157, 159, 193 volume of blood 123
production 15 gene therapy 27 Golgi apparatus 14 heart attacks 127, 128, 226
storage 158, 160 genes gonadotrophin-releasing heart disease 226
fat, dietary 138, 145 hormone 222 heart rate
fat tissues 140 alleles 17 goose bumps 30, 31 action/relaxation 68–69
fatty acids 145, 158–59, 161 complement at fertilization granulocytes 46, 169, 174–75 cardiovascular exercise 132
fear 242 gravity sense 93 exercise benefits 135
feces 141, 146–47 208, 210 grayscale vision 83 exercise intensity 133
feelings see emotions dominant and recessive forms grinding teeth 43 fight or flight response 241
feet 36, 37, 173 growth charts 39 sexual attraction 244
femur 37, 51 211 growth hormone 38, 193, 197, heartbeat 123, 128, 129
fertility treatments 209 expression 17, 22–23 199 heartburn 143
fetuses 212–13 function 20–21 guanine 16, 17 height 39
fever 176, 182, 183 gender determination 23 Helicobacter pylori 148
fibula 36, 37 gender-linked 211 H hemoglobin 116–17, 127, 139,
fight or flight response 191, 193, gene swapping 19 157
240–41 heredity 210–11 hair, body 30, 74, 222 heparin 156
fingerprints 32 length 16 hair cells, ear 13, 89, 92, 93, 95 herd immunity 184
fingers 55 mutations 21 hair, scalp 34–35, 225 heredity 17, 210–211
fingertips 75, 76 number 16, 17 hallucinations 247 herpesvirus 176
fitness level 134–35 transcription 22 hands 36, 55, 75, 109, 172 hiccups 119
flatulence 149 translation 20–21 hay fever 187 high blood pressure 226
flicker fusion 85 genitals, female headaches 63 high-protein diet 161
flu 182–83 menstrual cycle 206–207 hearing higher brain 62, 63
follicle-stimulating hormone microbes 172 higher cortex 79
(FSH) 206–207 pregnancy 208–209 aging 95, 225 hippocampus 233, 240
food sperm travel 205 cochlear implants 95 histamines 46, 174–175, 183,
allergies 186 structure/components 205, hair cells 13, 89, 92, 93, 95 186, 187
localizing sound 90–91
207 pitches 89
genitals, male 172, 204–205 problems 94–95
ghrelin 140, 198
giardia 177

HIV (Human Immunodeficiency PTH 192, 194, 195 incisors 42–43 joints
Virus) 176, 226 puberty 222–223 incus (anvil) bone 88 dislocations 49, 70
receptors in cells 192, 193 indigestion 143 double-jointed people 41
hormone therapy 193 relaxin 153, 216 infections flexion and extension 54
hormones serotonin 79, 135, 198–199, function 40
bacterial 174–75, 176 osteoarthritis 51
adenosine 234, 235 238, 243, 244 barriers to pathogens 168–69 position receptors 101
ADH 152–153 sex hormones 38 in broken bones 48 replacement 51
aldosterone 199 sexual attraction 244 defenses against 31, 168–69 rheumatoid arthritis 186
balance 194–95 stress-management 198, 199 in ears 94 sprains 71
calcitonin 190, 195 testosterone see testosterone fungal 177 structure/components 40
cortisol 109, 196, 198, 199, thyroid-stimulating hormone immune response 174–75, types 40–41

238, 240, 241 199 180–81, 183 K
daily rhythms 198–99 triggers 192–193 infectious diseases 176–77
dopamine 197, 238, 244 vasopressin 245 necrosis of cells 15 keratin 21, 32, 34–35, 139
emotions 238–239 housekeeping proteins 23 protozoan 177 ketone bodies 161
epinephrine see epinephrine human chorionic gonadotropin spread 177 kidney stones 150
exercise benefits 197 (hCG) 215 in teeth 43 kidneys
fat-insoluble 193 human genome 16 testing for antibodies 178
fat-soluble 192 humerus 36, 49, 54, 55 types 168 calcium excretion 195
feedback loop 194–95 hunger 140, 198 vaccines against 184–85 filtration 150–51
“feel good” 197 hydration 131, 152–53 viruses 176, 182–83 hormone production 191
fight or flight response 240 hypodermis 31, 32, 47 infertility 209 structure/components 150–51
follicle-stimulating hormone hypothalamus 140, 152, 190, influenza 182–83 vitamin D activation 194
193, 222 injuries 70–71 water balance 153
(FSH) 206–207 insulin 149, 158, 160–61, 191,
functions 192–193 I 196, 197, 200–201 L
gastrin 191 intermittent fasting 162
ghrelin 140 immune system intestines lactase 164
glucagon 159, 191, 193 adaptive immune system 169 action/relaxation 68–69 lactic acid 43, 57, 121, 130–31
gonadotropin-releasing aging 175 calcium absorption 194, 195 Lactobacillus 148
antibodies 172–73, 178–79 celiac disease 165 lactose intolerance 164
hormone 222 B cells see B cells digestion 141, 144–47 larynx 104, 222
growth hormone 38, 193, 197, barriers to pathogens 168 gas production 149 laughter 128
calming 173 hormone production 238 laxatives 141
199 cancer, fighting 180–81 irritable bowel syndrome (IBS) learning 62, 230–31
human chorionic fight or flight response 241 left-handedness 64
innate immune system 169 165 legs 37, 41, 46, 127, 173, 212
gonadotropin (hCG) 215 lifestyle impacts 196–197 lactose intolerance 164 lens 80, 81, 86, 87, 201
hunger/satisfaction 140, 198 memory 169 microbes 148, 172 lentivirus 176
problems 186–87 nutrient absorption 149 leptin 140, 198, 222
estrogen see estrogen response to bacterial touch sense 74 levers, body 55
insulin 149, 158, 160–61, 191, infections 174–75 iris 80, 81 lifestyle 196–197
196, 197, 200–201 response to viruses 183 iron 116, 117, 139, 149, 157 ligaments 37, 40, 41, 49, 70, 71,
fatigue 234 Rhesus babies 179 irritable bowel syndrome (IBS)
leptin 140, 198, 222 self/nonself distinction 165 216
lifestyle impacts 196–97 170–71 itching 46, 79 light spots 82
long-term pair bonding 245 T cells see T cells lipase 143, 145
melatonin 190, 196, 198–99 J liver
menstrual cycle 206–207 immunocompromised
muscle growth 133 conditions 187 jaws 41, 44–45, 101 action/relaxation 68–69
norepinephrine 243 jet lag 199 bile 141, 144, 155, 157
oxytocin 192, 197, 238, 245 immunotherapy 180–81
placental 215
production 15, 157, 190–91
progesterone 191, 206–207,

214, 215

252 253

blood supply 154 mammary glands 172 body levers and fulcrums 55 nerve endings
damage 157 mast cells 169, 175 breathing 132 in clitoris 204
fat metabolism 156 meiosis 19 contraction/relaxation 57, in ear hair cells 95
filtration speed 155 melanin 31, 33, 34, 35, 225 in hands/fingers 75, 76
functions 156–157 melatonin 190, 196, 198–199 58–59 in nasal passages 118
gluconeogenesis 156 memory 231–233, 237, 243, 247 control by nervous system in skin 30, 31, 74, 78
glycogen storage 157 menopause 206 60–61 on the tongue 99
heat generation 157 menstrual cramps 206 cramps 57
hormone production 157 menstrual cycle 206–207, 223, energy use 158–59 nerves/nervous system 10–11
ketone body production 161 exercise benefits 135 action/relaxation 68–69
manufacturing function 157 245 eye muscles 80, 81 aging 225
mineral storage 157 messenger RNA (mRNA) 14, 20, facial expressions 107 autonomic 69
nutrient processing 154–55, flexion and extension 54–55 in the brain 64, 65
21 growth 133 brain see brain
156, 157 microbes hair erector muscles 30 breathing feedback system 112
protein synthesis 157 jaw muscles 44–45 fight or flight response 240–41
regeneration 156 friendly 146, 148–49, 164, lactic acid 131 hearing 89
storage function 157 172–73 muscle fibers 56 injuries 70
structure/components 154–55 muscle tissue 13 learning 230–31
toxin detoxification 156 harmful 148, 172–173; see paralysis during sleep 234, memory 231, 232, 233
vitamin storage 157 also infections message transmission 64,
lock and key theory 97 237 66–67
low-carbohydrate diet 161 microtubules 15 pulling and lengthening 59 nerve cells 13
lungs milk teeth 42 pulling and shortening 58 nervous tissue 13
action/relaxation 68–69 minerals pulling without shortening 59 pain, sensing 78–79
allergy response 187 reflex reactions 60–61 pins and needles 66
asthma 187 calcium 36, 50, 51, 162, 190, resistance training 133 sensory input/action output
breathing 112–13 192, 194–95 skeletal muscle cells 13 60–61
cancer 226 slow-twitch/fast-twitch fibers sight 82–83
capacity 132 chloride 146 smell sense 97
coughing 118–19 copper 157 57 speech 105
disease 226 iron 116, 117, 139, 149, 157 smooth muscle cells 13 speed 66
exercise benefits 134 microbial digestion 149 sprains and strains 70, 71 spinal cord see spinal cord
fetal growth and development phosphate 16, 17, 36 stretch receptors 100 structure/components 66–67
potassium 147 structure/components 56 sympathetic and
212 requirement 138, 139 teamwork 54 parasympathetic 69
gas exchange 114–15, 120 sodium 146, 147 tendons, control by 55 touch sense 74–75
infections 226 storage in liver 157 tension 58–59 see also nerve endings
structure/components 112–13, mirror box therapy 100 warm up, exercise 58
114–15 mitochondria 14, 15 weight lifting 58–59 nervous tissue 13
surface area 113 mitosis 18 music 91 neurons 66–67, 90, 91, 163, 197,
lust 244 molars 42, 43 myosin 56–57, 131
lying 109 morning sickness 215 234
lymph system 170, 171, 178 motor cortex 105, 236, 237, N neurotransmitters 67, 89, 135,
lysavirus 176 239
mouth nails 34, 35 197, 230, 235, 237
M eating 140, 142 natural killer (NK) cells 169 nonverbal communication
microbes 172 near-death experiences 227
macrophages 126, 127, 169, speech 104 nearsightedness 86 108–109
174–75, 178, 179, 180 teeth 42–43 necrosis 15 norepinephrine 243
temporomandibular joints 41 nematodes 177 nose
maggot therapy 175 tongue see tongue nerve bundles 62
malleus (hammer) bone 88 muscles nerve cell bodies 62, 67 bone and cartilage 48
aerobic respiration 131 breaking 48
anaerobic respiration 132 cold and flu symptoms 183
arm muscles 54–55 microbes 172
body heat generation 59

sense of smell 96–97 purpose 78 progesterone 191, 206–207, 214, rigor mortis 227
sneezing 118 referred 78 215 RNA polymerase 22
snoring 118 reflex reactions 60–61 road accidents 226
nucleus, cell 14, 20 sensing 78–79, 99 propyonic acid 149 rods 82–83
nutrition 138–39, 140, 149, 219; strains and sprains 71 prostaglandins 78 rough endoplasmic reticulum
see also digestive system; whiplash 71 protease 145
eating painkillers 78, 79 protein, dietary 138, 161 14
paleolithic diets 162–63 proteins
O pancreas 140, 141, 144, 158, S
159, 191, 200–201 functions 16
obesity 160 parasites 168, 176–177 housekeeping 23 saccule 93
obsessive compulsive disorder parathyroid glands 190, 192, packaging in vesicles 14 sacrum 37
194 production in liver 157 salivary glands 142
(OCD) 242 pathogens 168, 176–77, transfer out of cell 14 salmonella bacteria 176
olfactory receptors 97 180–181, 184; see also translation 14, 16, 20–21 sarcomeres 57
opioids 79, 239 infections protozoan infections 177 scabs 46
optic nerve 80, 81, 87 pelvis 37 PTH (parathyroid hormone) scars 47
organs 12, 212–13; see also penis 204–205 192, 194, 195 scratching 79
perspective 85 puberty 222–223 sebum oil 31, 47
specific organ phagocytes 168, 169, 179 pupils 68, 81, 244 semen 204–205
orgasms 204 phantom limb pain 100 senses
ossicle bones 88, 94 phobias 242 R
osteoarthritis 51 phosphate 16, 17, 36 baby’s 219
osteoporosis 48, 50–51 photoreceptor cells 13 radius 49, 54 body ownership 101
ovaries pineal gland 190 reading faces 106–107 body position 100–101
pins and needles 66 rectum 147 in dreams 236
hormone production 191, pituitary gland 152, 190, 193, red blood cells 13, 16, 116–17, fetal development 213
192, 223, 238 206, 207, 240, 241 hearing see hearing
placenta 179, 208, 209, 212–13, 120, 139 integrated 102–103
menstrual cycle 206–207 215, 216, 217 reflex reactions 60, 218 memory 231
oxygen post-traumatic stress disorder relaxin 153, 216 sight see sight
(PTSD) 243 REM (rapid eye movement) smell 96–97
altitude effects 115 potassium 147 taste 98–99
circulation 115, 116–17, prefrontal cortex 236, 243, 244 sleep 234, 235, 236, 237 touch 74–77, 99
pregnancy repressor protein 22 sensory cortex 76–77
120–21, 128, 134 birth 216–17 reproductive system sensory homunculus 76
daily amount used 116 changes to mother’s body serotonin 79, 135, 198–99, 238,
energy function 116, 130 fertilization 208–209 243, 244
gas exchange 115, 117 214–15 gender determination 23 sesamoid bones 36
heart’s requirement 128 fertilization 208–209 genitals, female 205, 207 sex 204–205
oxygen intake fetal growth and development genitals, male 204–205 sex determination 16
action/relaxation 68–69 heredity 210–11 sexual attraction 244–45
breathing feedback system 112 212–13 menstrual cycle 206–207 shoulder blades 37, 54, 55
during/after exercise 130–31, food cravings 214 reproductive cells 13 sight
132 length 217 sexual intercourse 204–205 3-D vision 84
exercise benefits 134 morning sickness 215 resistance training 133 aging 86, 87, 225
extraction in alveoli 114 Rhesus babies 179 respiration see breathing astigmatism 86
VO2 max 135 stretch marks 215 respiratory system 10–11 binocular vision 84
oxyhemoglobin 117 premolars 42 lungs see lungs brain processing 84–85
oxytocin 192, 197, 238, 245 PRICE technique 71 trachea 112, 114 bright and dim light 81
primitive brain 62, 63, 68–69 retinas 80, 81, 82, 83, 86, 87, 93 cataracts 86
P probiotics 149 Rhesus factor (Rh) 179 color blindness 87
rheumatoid arthritis 186
pacemaker 122–23 ribosomes 14, 20–21
pain right-handedness 64

back pain 70
nerve pinching 70

254 255

color consistancy 85 sleep hormone production 140, function 54
color vision 83 body paralysis 234, 237 191 length 54, 55
damage and disorders 86–87 circadian clock 198–99 sesamoid bones 36
development 219 deprivation 235 microbes 148 sprains and strains 71
flicker fusion 85 dreaming 236–37 pregnancy effects 215 temporalis tendon 44
focus 81 levels 234, 235 structure/components 12, tension receptors 100
glaucoma 86 melatonin 196, 198–99 testes 191, 205, 223, 238
grayscale vision 83 memory consolidation 237 143 testosterone
image formation 81, 82–83 REM (rapid eye movement) ulcers 148 emotions 238
long-sightedness 86 sleep 234, 235, 236, 237 strains 71 exercise benefits 197
nerve signals 83 sleep pressure 234 streptococcus bacteria 176 nightly surge 198
nutrition for 139 sleep talking 236 stress 198, 199, 241 production 191, 223
perspective 85 sleepwalking 234, 236 stretch marks 215 sexual attraction 244, 245
photoreceptor cells 13 strokes 226 superman pose 109
short-sightedness 86 sleep deprivation 235 sugar trap 160–161 thalamus 62, 63, 79, 240, 243
tunnel vision 240 sleep talking 236 sugars 57, 68, 116, 138, 139, theory of mind 220
vision tests 87 sleepwalking 234, 236 144–45, 147; see also glucose thymine 16, 17
see also eyes slipped discs 70 superman pose 109 thymus 171, 190
singing 105 smell, sense of 96–97 suprachiasmatic nucleus (SCN) thyroid gland 190, 195, 199
sinoatrial node 122–23 smoking 196 198 thyroid-stimulating hormone
skeletal system see bones smooth endoplasmic reticulum swallowing 142 199
skin sweat glands 30 tibia 37
acne 47, 223 15 synaesthesia 247 tickle response 77
aging 32, 225 smooth muscle 12, 13, 124, synovial fluid 40 tiredness 234–235
area 31 systems 10–11 tissues
blisters 47 125 stem cell engineering 25
burns 47 sneezing 118, 176 T transplants 25
color 33 snoring 118 types 13
damage 46–47 sodium 146, 147 T cells tongue
as defensive barrier 31, spatial awareness 237 B cell stimulation 178, 180 body position sensors
speech 101, 104–105 bactericidal chemicals 175
32–33 sperm 13 cancer, fighting 180–181 101
eczema 186 count 181 eating 142
functions 30–31 ejaculation 204, 205, 223 maturation/release 171 other receptors 99
healing 46–47 fertilization of egg 208–209 migration to lymph nodes 171 sensitivity 76
layers 31, 32 heredity 210–211 production 170, 190 snoring 118
microbes 173 journey to fallopian tubes 205 self test 171 speech 104
permeability 31 production 19, 223 taste receptors 98–99
scabs 46 size 205 types 181 touch 74–77, 99
scars 47 spinal cord taste 98–99 toxins
self-renewal 32 message transmission 62, 68, taste buds 98 damage from 15, 26, 168
stretch marks 215 tattoos 32 detoxification in liver 156
stretch receptors 101 69, 78, 79, 237 tears 81 released as defense 148
structure/components 30–31, reflex reactions 60, 61 teenagers 38, 222–223 trachea 112, 114
sensory input/action output teeth 42–43 transfer RNA (tRNA) 20, 21
32 telomeres 224, 225 transplants 25, 170
temperature control 30 60, 61 temperature, control 30 treponema bacteria 176
touch sense 74–75 spine 36, 50, 70, 71, 212, 215 temperature, sensing 77, 99 triceps 54, 55
vitamin D synthesis 33 sprains 71 temporomandibular joints 41, trichomonas 177
weight 12 stapes (stirrup) bone 36, 88 turning sense 92
wound response 174–175 stem cells 23, 24–25, 170, 217 44–45 twins 170, 208, 209
skull 37 stomach tendons

action/relaxation 68–69 Achilles tendon 37, 54, 55, 71
butterflies 69 in fingers 55
digestion 141, 143
gastric juices 143

U vision see sight Acknowledgments
vision tests 87
ulcers 148 visual cortex 85, 237, 240 DK would like to thank the following people for help in
ulna 49, 55 vitamins preparing this book: Amy Child, Michael Duffy, Jon Durbin,
ulnar nerve 37, 70, 71 Phil Gamble, Alex Lloyd, and Katherine Raj for design
ultraviolet light 26, 31, 33 microbial production/ assistance; Nadine King, Dragana Puvacic, and Gillian Reid for
urea 150, 151 secretion 149 pre-production assistance; Caroline Jones for indexing; and
ureters 150, 151, 153 Angeles Gavira Guerrero and Andy Szudek for proofreading.
urinary system 10–11, 150–53 requirement 138
storage in liver 157 The publisher would like to thank the following for their kind
bladder 69, 150, 151, 153, 215 vitamin A 139, 155, 157 permission to reproduce their images:
kidneys see kidneys vitamin B 146, 149, 157
ureters 150, 151, 153 vitamin C 126, 138 p.85: Edward H Adelson
urine 150–51, 153, 195, 212 vitamin D 30, 31, 33, 36, 50, p.87: Photolibrary: Steve Allen
uterus
birth 216–17 157, 194, 195 For further information see:
embedding of fertilized egg vitamin E 157 www.dkimages.com
vitamin K 126, 146, 149, 157
208, 209 VO2 max 135
expansion during pregnancy vocal chords 104
vomiting 165
215
menstrual cycle 206, 207 W
utricle 93
water
V absorption 146
balance 152–53
vaccines 176, 180–81, 184–85 elimination 151
vagina 204–205, 223 requirement 138, 139
varicose veins 127
vasopressin 245 weight 158, 159, 160–63, 196
veins whiplash 71
wisdom teeth 42, 43
blood pressure 124 wounds 46–47, 174–75
carrying oxygen-poor blood
Y
116, 125
carrying oxygen-rich blood yawning 119

114 Z
deep vein thrombosis 126
hepatic 154–55 zoonotic diseases 177
penile erection 204
renal 150, 151
varicose veins 127
vertebrae 50, 70
vesicles 14, 15
vibrio bacteria 176
viruses
cell invasion 168, 182
cold and flu 182–83
friendly 172–73
gene therapy 27
symptoms 183
types 176
vaccines 176, 184–85