Oasis School Science and Technology 10 New

Oasis School Science and Technology - 10 101 plant and pure dwarf pea plant were crossed because dwarf is a recessive character. The recessive character never appears in the first filial generation when two purebreds are crossed. 8. Monohybrid cross between two hybrid parents gives birth to purebred and crossbreds. Hybrid organisms contain both the dominant genes as well as recessive genes. According to the law of purity of gamete, the genes won’t blende. So, during the monohybrid cross of hybrid parents, the dominant character, the recessive character and the hybrid characters, all of them, appear in offspring. 9. Is Mendel’s experiment applicable to animals too? Or is it applicable to plants only? Explainwith the help of an example. Mendel’s experiment applies not only to plants but also to animals. Let’s suppose there is an animal, it also has chromosomes in its cells similar to the plants. The chromosomes are in pairs as an allele. The animals also have meiosis cell division to form gametes similar to plants. When crossed animals also inherit traits from their parents. Therfore Mendel’s law must be applicable to animals too. 10. When two hybrid long-winged drosophila were crossed, 25% of drosophila had a short wing. Which law can explain it? Describe the law with an example. When two hybrid long-winged drosophilas were crossed, 25% of drosophila had short wings. This case can be explained by Mendel’s second law of genetics, the law of purity of gametes. It is also called the law of segregation. The law segregation explains that during a monohybrid cross, each factor that controls each contrasting character is inherited independently. They are not affected by others and they do not blend. For example: When pure long-winged (LL) drosophila (dominant) and pure short-winged (ll) drosophila (recessive) are crossed, 100 % hybrid organisms are formed and the genes are transferred into them independently. When the hybrid offspring of the first filial generation is crossed, then the genes are again independently inherited by the second filial generation. As a result, 25 % pure long-winged, 25 % pure short-winged and 50 % hybrid longwinged drosophila were seen in the second filial generation, which was hidden in the first generation. O O l l Ll L Ll Ll L Ll + Hybrid long-winged Hybrid long-winged Hybrid long-winged Hybrid long-winged O O L l LL L Ll Ll l l l + Pure long-winged Hybrid long-winged Pure short-winged Hybrid long-winged

102 Oasis School Science and Technology - 10 Exercises 1. Choose the best answer from the given alternatives. a. What are the traits that transfer from parents to offspring called? i. contrasting characteristics ii. hereditary characteristics iii. recessive characteristics iv. dominant characteristics b. Radha and her twins look different. What is this difference called? i. variation ii. heredity iii. evolution iv. mutation c. If TT stands for pure tall and tt stands for pure dwarf, what does the allele Tt stand for? i. pure bred ii. pure tall iii. pure dwarf iv. hybrid tall d. Where are the genes located? i. cytoplasm ii. chromosome iii. ribosome iv. centrosome e. What percentage of second filial generations are pure recessive? i. 25% ii. 50% iii. 75% iv. 100% f. What is the transfer of characteristics from parents to the offspring called? i. evolution ii. dominant characters iii. recessive characters iv. heredity 2. Define the following terms with required examples. a. Heredity b. Variations c. Genetics d. Allele e. Homozygous f. Heterozygous g. Dominant character h. Recessive characters i. Phenotype j. Genotype k. Monohybrid cross l. Dihybrid cross m. Contrasting characters n. Law of dominance o. Law of purity of gametes 3. Answer the following questions in very short. a. Who is called the father of genetics? b. When a black mouse was crossed with the white one, all of the new-borne mice were black? Which one is the dominant character in this case? c. What is the smallest hereditary unit called? d. What does it mean by first filial generation? f. Write the names of the organism in which Mendel carried his experiments.

Oasis School Science and Technology - 10 103 g. Write the phenotype ratio and genotype ratio of a monohybrid cross. h. A white dog is born from black parent dogs. Which law of genetics can explain this? 4. Give reasons. a. Individuals of the same species also differ from each other. b. Children have some physical features similar to their parents. c. Every offspring of the first filial generation is hybrid. d. Mendel chose the pea plant for his experiment. e. Every living being gives birth to its own kind of offspring. 5. Differentiate between the following. a. Pure organisms and hybrids b. Dominant character and recessive character c. Phenotype and genotype d. Monohybrid cross and dihybrid cross 6. Answer the following questions in short. a. What is the function of a gene? b. What is the significance of Mendelism? c. Describe the law of dominance with an example. d. Even though no white mouse is seen in the first filial generation, 25% of them reappear in the second filial generation. Which law is related to it? Describe that law. e. Write any two reasons for selecting pea plants by Mendel for his experiment. f. Explain the reason that only one characteristic is found expressed in F1 generation of Mendel's experiment. g. Mating of black and brown dogs takes place and all the offspring produced in F1 -generation are black. Why isn't their brown offspring? 7. Answer the following questions on the basis of the given table. The result obtained by crossing a black rat with a white rat is shown in the given checker board. On this basis, answer the following questions. i) Which filial generation does this result belong to? ii) Write down the ratio of dominant and recessive characteristics. iii) Which one is a pure black rat? 8. Answer the following long questions. a. Describe Mendel’s pea plant experiment. b. How is a hybrid obtained? Write in brief. O O B b BB B Bb Bb b bb +

104 Oasis School Science and Technology - 10 c. Do Mendel's laws apply to human beings too? What difficulties would Mendel have faced if he had carried out his experiment on human beings instead of pea plants? d. If the monohybrid cross between a black male cat and a brown female cat takes place, all offspring of F1 -generation were black. Why were there no brown offspring in F1 -generation? Show this process with the help of a chart up to F2 generation. Write down the genotype ratio of this process. e. A hybrid tall pea (Tt) plant is crossed with a dwarf pea (tt) plant to get F1 -generation. Show it with genotype and phenotype. f. What are the laws derived from Mendel's experiment? Show in the chart of F1 -generation of round and wrinkled seeds of pea plants when they are crosspollinated. g. Show the genotype and phenotype of offsprings produced by crossing drosophila with long wings and short wings up to the second filial generation. h. Draw a chart to show both phenotype and genotype of the result obtained in the first and second filial generation of offsprings of the mouse, having black colour and white colour according to Mendel's experimental result. With the help of the same chart write the ratio of phenotype and genotype of the second generation. 9. The result obtained by first cross-pollination and then self-pollination between pure red flowering pea plant (RR) and pure white flowering pea plant (rr) is shown in the table. Answer the questions below: i. Which filial generation does this result belong to? ii. What is a hybrid? What is the percentage of hybrid pea plants in this generation? iii. Which pair of alleles indicates the pure white flowering pea plant? O O R r RR R Rr Rr r rr +

Oasis School Science and Technology - 10 105 Key terms and terminologies 1. Genes : Genes are the smallest hereditary units. The genes are made up of DNA sequences. 2. Genetic engineer : A genetic engineer is someone who studies the genes of living things. 3. Genetic technology: The technology in which the genes are modified, cut, removed or transferred using biotechnology is called genetic technology. 4. DNA testing : The technology which helps to count the number of chromosomes and identify changes in genes, chromosomes and genomes is called DNA testing. 5. Breeding : The way in which plants and animals produce new organisms through sexual reproduction is called breeding. 6. Selective breeding : The process in which humans identify certain special traits in an organism and take steps to breed them so that a new organism will have those traits is called selective breeding. 7. Inbreeding : Inbreeding is the act of breeding between males and females who UNIT 4.3 GENETIC TECHNOLOGY Estimated teaching periods Theory 4 Practical 1 • Introduction to genetic technology • Role of DNA tests in various investigations • Methods of selective breeding • Introduction, examples, merits and demerits of cross-breeding • Introduction to the in vitro fertilization and artificial insemination The Sequence of Curriculum Issued by CDC Thomas Hunt Morgan is noted for his discovery of the role of chromosomes in heredity. He was born in America on 25th September 1866 and died on 4th December 1945. He was an evolutionary biologist, embryologist and geneticist. He won the Nobel Prize in Medicine in 1933 for discovering and elucidating the role of chromosomes in heredity. He discovered linked genes and sexlinkage. About the Scientist Thomas Hunt Morgan

106 Oasis School Science and Technology - 10 are closely related genetically. It is breeding between first-degree relatives. 8. Line breeding : The process of breeding between males and females who are second or third degree relatives is known as line breeding. 9. Outcrossing : Breeding between males and females who have not been related for at least four to six generations is known as outcrossing. 10. Self-pollination : The transfer of pollen grains from anther to stigma of the same flower or flowers of the same species is called self-pollination. 11. Cross breeding : Cross breeding is the process of mating two purebred individuals from different species, breeds, or varieties to create new offspring. 12. IVF : The process in which ovum and sperm are fertilized outside the female body in the glass vessels is called in vitro fertilization (IVF). 13. Artificial insemination: Artificial insemination (AI) refers to the meaningful implantation of sperm into a female's cervix or uterus. 14. Intracervical insemination: When unwashed raw sperms or sperms donated by a sperms bank is inserted into the vagina, this is known as intracervical insemination. 15. Intrauterine insemination: Intrauterine insemination occurs when washed sperms are introduced directly into the uterus. Introduction Do you know why children resemble like their parents? Children typically resemble their parents. For example, a child's eyes or nose may be the same as a parent's. Children can inherit certain traits from their parents, including intelligence, physical abilities, and sometimes even disease resistance. Gregor Johan Mendel discovered that traits may be dominant or recessive when they are passed down from parents to offspring. He is known as the father of genetics. Later, many other scientists conducted additional research into heredity and found that genes are involved in the transmission of inherited traits and qualities to offspring. This is known as Mendel’s theory. Genes are the smallest hereditary units. The genes are made up of DNA sequences. A chromosome is made up of them. There are hundreds to thousands of genes on a single chromosome. Information contained in an organism's genes determines its physical characteristics. It also determines how a living thing eats, how well it can fight off illness, and which diseases it is vulnerable to. Reasonable Fact Children are similar to the parents. Children are similar to their parents because they receive genes from their parents which bring genetic features. Fact File In 1973, the first genetically modified animal was created. It was a bacterium.

Oasis School Science and Technology - 10 107 Genetic Technology Genes make up a living thing. Our genes determine things like our height, skin, tone, eye color, nose shape, and other physical traits. A genetic engineer is someone who studies the genes of living things. Genetic engineers typically add, remove, or cut genes from chromosomes. Sometimes they pass genes from one organism to another. They also alter the cell's genetic make-up. Due to changes in their genes, the organism's physical characteristics, resistance to disease, adaptation traits, physical capabilities, and intellectual capabilities will all be significantly altered. These are known as genetically modified organisms. As was mentioned above, genes contain all of the information necessary for building our bodies, including physical and mental skills, survival instincts, disease resistance and many other traits. We also discovered that genetic engineers could change the genes to change how organisms function physically. The technology in which the genes are modified, cut, removed or transferred using biotechnology is called genetic technology. Genetic engineering comes in a variety of forms. Gene testing, gene therapy, vaccines, genetic engineering, and other common applications of genetic technology are just a few. Some examples of genetic technology 1. It is known that human genes can be transferred to certain bacteria to produce insulin. Diabetes is cured with the hormone insulin. This is known as genetic engineering. 2. Certain genes from one plant can be inserted into the genomes of other plants to create genetically modified plants. It provides additional benefits to the plants, such as increased nutritional value, resistance pest and drought, etc. It increases agricultural output. Fig: genetically modified banana plant Fact File In genetic technology there occurs change of one pair of nitrogen base(A-T or C-G), cut or add of gene to develop a new character. Figure: Inserting gene in a DNA Fact File Chromosomes can be completely synthesized in a laboratory by genetic engineers.

108 Oasis School Science and Technology - 10 3. Another application of gene technology is vaccines. Numerous deadly diseases, including measles and chicken pox, are prevented by vaccinations. Since the vaccine contains the virus' genes, when we receive it, our bodies produce antibodies to fight off actual viruses. 4. Scientists can insert modified virus genes into a young plant. The young plant develops and produces fruits that contain virus genes. We won't get sick if we consume these fruits. But the body gets ready to fight the virus with antibodies. It protects us from future illnesses. 5. DNA is injected into a patient during gene therapy to treat genetic disorders. It is also used to turn off specific genes in cancer-causing cells. 6. A type of genetic technology used to diagnose genetic disorders is genetic testing. Additionally, it is used to find chromosomal defects in the foetus, like Down's syndrome. DNA testing is another name for genetic testing. Fig: chicken pox vaccine Fig: gene therapy Fig: genetic testing Reasonable Fact Scientists mix DNA of a virus into the DNA of banana plants. Scientists mix virus DNA into banana plant DNA, so that the banana fruits contain virus genes. It acts as a vaccine, protecting us from disease. Activity 1 How do gene technology help to develop a vaccine? Learn more about it from the internet. Potential issues of genetic technology Humans can benefit from genetic technology by preventing diseases, curing diseases, and ensuring food security. However, there are risks associated with any form of genetic technology. Some of them are discussed below: i. Genetically modified crop plant can be transferred to wild plants. It has the potential to harm the ecosystem. ii. Farmers will be forced to buy expensive genetically modified seeds. iii. Transferring genes from one species to another is an unethical work. iv. Use of genetic modification to treat diseases is an improvement rather than a treatment. v. Superhuman soldiers can be created using genetic technology.

Oasis School Science and Technology - 10 109 Measures against genetic technology Many nations have laws regulating genetic technologies because they can actually be used for unethical experiments. For example: i. The modification of genes in the human embryo is prohibited. ii. Human cloning is illegal and punishable by death. DNA Testing Every living organism has deoxyribonucleic acid (DNA), which serves as the genetic code. Every person has a different DNA. Every cell in the body has instructions on how to function properly. Our parents pass on their DNA to us. Our health and body are affectd by DNA. Therefore, DNA testing will be very beneficial in the medical field and other fields. It is a type of genetic engineering. The number of chromosomes in a human cell could be counted by biologists in the 1950s. A human cell typically contains 46 chromosomes, or 23 pairs of them. Serious defects in the body can result from the chromosomes' rearrangement, number, or increase or decrease. Chromosome disorder is the name given to such a condition. The technology which helps to count the number of chromosomes and identify changes in genes, chromosomes and genomes is called DNA testing. DNA testing looks at our DNA's chemical database. It helps in exposing gene changes that may result in disease. DNA testing is growing popular among the public, medical fields and criminal investigation. Role of DNA testing 1. DNA testing is carried out to investigate or rule out potential chromosomal or genetic disorders. 2. Based on a person's DNA test, doctors can recommend medications or create a treatment plan just for them. 3. To determine whether a person is biologically related to a child or not, a DNA test can be performed. For example, DNA paternity testing. 4. Nowadays, many people use DNA testing to determine their ancestry. 5. Learning about various aspects of evolution is also beneficial due to genetic test. 6. It is used to test if an organ donor and receiver have a genetic match. 7. DNA testing is frequently employed in investigations. Crimes are investigated using Fact File DNA in identical twins will be 100% alike, but their fingerprints will be different. Fig: DNA testing to find ancestry Fact File The Central Police Forensic Science Laboratory (CPFSL) of Nepal Police started DNA testing in Kathmandu in 2015 AD.

110 Oasis School Science and Technology - 10 DNA test. In the case that a suspect is present, their DNA is examined. The result is then matched with the DNA test result of any samples taken from the crime scene. After comparing the two results, the judge can draw a conclusion about the case. For example: Imagine there has been a robbery. After that, any samples from the crime scene will be collected by the criminal investigation department. For example, it might include fingerprints, hair, blood, sweat, and tears. A DNA test will be performed. They will then carry out additional research and identify some suspects. The suspects' DNA can be tested, and the results can be added up. If the suspect is a criminal or not, they can draw that conclusion. DNA testing frequently helps in the resolution of rape and murder cases. Question to think If a child separted from parents in early age do not know who his parents are? How can he try to find the parents? Breeding The act of producing a new, unique organism from its parent or parents is known as reproduction. Every living thing reproduces sexually or asexually. During sexual reproduction, two parents are involved. One of them is male and other one is female. The male and female organisms of same species take part in sexual reproduction. So, the way in which plants and animals produce new organisms through sexual reproduction is called breeding. The organisms that take part in breeding are called breeding pairs. Wild breeding refers to the natural process by which wild animals reproduce. In plant, sexual reproduction is also referred to as breeding. It is also popular in animal husbandry. Humans select specific characteristics of an organism and use them to breed new organisms. Fig: holeistein cow Fig: cross breed goat Fig: cross breed buffalo Reasonable Fact Most wild animals breed in spring. Most wild animals breed in the spring because it is warm and there is plenty of food in the forest. Fact File Genetic variation is necessary to make progress in breeding in successive generations.

Oasis School Science and Technology - 10 111 Activity 2 Visit a cow farm and observe the cows. Make a questionnaire and ask farmers. Collect information on purebred cows and crossbred cows. List out their characteristics. Selective Breeding Humans can keep animals or plants having desirable characteristics while discarding the others. Humans, for example, captured and tamed less aggressive wolves. It gave birth to a new species of the dog, after thousands of years. Similarly, cauliflower is a highly modified version of a mustard family cabbage. Cauliflower exists because farmers selected seed from plants with better flowers and bred them for many years. It is known as selective breeding. The process in which humans identify certain special traits in an organism and take steps to breed them so that a new organism will have those traits is called selective breeding. It is also called artificial breeding. Selective breeding helps an organism to evolve faster. Animal husbandry frequently uses animal breeding. It helps us grow hens that can produce a lot of eggs or meat. Sheep are available with a lot of meat or wool. A breed of cow that produces a lot of milk can be used by farmers to fertilize their own cows. Fig: crossbred hen Fig: cross bred dog Fig: cross bred sheep Plant breeding is also in practice since ancient times. It helps farmers to grow highyielding varieties of crops. It is also used to grow plants that can resist viruses, bacteria, fungi and drought. Fig: crossbred paddy Fig: crossbred maize Fig: crossbred tomato Breeding back helps to re-assemble genes to give birth to plants or animals that are already extinct.

112 Oasis School Science and Technology - 10 Demerits of Selective Breeding 1. As a result of selective breeding plants and animals which have only one type of genetic characters grow in large population. 2. Genetic diseases and infectious diseases can transfer from generation to generation. 3. Selective breeding is also called artificial selection because it is done by the human choice. It may reduce biodiversity. Reasonable Fact Selective breeding affects biodiversity. Selective breeding affects biodiversity because we select only those animals and plants which have desired characters and discard others. In this process, some animals and plants which have one or few bad characters are left for breeding. It may extinct these animals and plants. Methods of Selective Breeding There are several methods for selective breeding. Some of them are described below: Inbreeding Inbreeding is the act of breeding between males and females who are closely related genetically. It is breeding between first-degree relatives. Inbreeding helps to bring uniformity in characteristics of that organisms. It is done to preserve certain trait of organisms which is desirable to humans. They are also called pure trait. For example, if we have a cow that is very healthy and gives a lot of milk, we can fertilize it with a bull which is genetically identical to our cow. So that newborn cow can also give a lot of milk. However, inbreeding has lots of side effects. For example, since male and female from same family is breeding, recessive characteristics can be seen in children. The offspring may be unhealthy physically and mentally. Inbreeding is considered a crime in human beings. Some examples of pure inbred are Siamese cat, Labrador retriever dog, etc. Fig: Siamese cat Fig: Labrador retriever dog Reasonable Fact Inbreeding is not good for humans. Inbreeding is not good for humans because the recessive characteristics are observed. The offspring suffer from genetic disorders, gene pool decreases and children can be violent.

Oasis School Science and Technology - 10 113 Line Breeding The process of breeding between males and females who are second or third degree relatives is known as line breeding. The genetic purity of plants and animals is increased as a result of line breeding. For example, suppose a goat had two female young. Each is taken away by two farmers. Both farmers have their own goat herds after few years. Since they are distant relatives, it is referred to as line breeding if the first farmer's goat and the second farmer's goat mate. In some ways, it helps to counter the negative effects of inbreeding. Self pollination The transfer of pollen grains from anther to stigma of the same flower or flowers of the same species is called self pollination. It results almost same types of offspring. Fig. self pollination Out-crossing Breeding between males and females who have not been related for at least four to six generations is known as outcrossing. Another name for it is outbreeding. It is advantageous to introduce genetic material from unrelated species into the breeding line. As a result, genetic diversity is increased because thre are breeding pairs of organisms from various bloodlines. For example, an out-crossing between a native Belgian cow and an imported English cow produced the Belgian blue cow. Cross breeding In all organisms, chromosomes exist in pairs. If both of the chromosomes of an allele are identical, then the organism is called purebred. All members of a purebred line share the same observable characteristics. Cross breeding is the process of mating two purebred individuals from different species, breeds, or varieties to create new offspring. As a result, alleles from both parents are present in the organism. The organism is referred to as a hybrid or crossbred because it has different chromosomes for each allele. Crossbreds are typically the offspring of different purebred species. Fig: Belgium blue cow

114 Oasis School Science and Technology - 10 Some examples of crossbreds 1. Mule : The horse and the donkey are two different species. When a male donkey and a female horse mate to produce offsprings, a mule is born. It is sterile, can carry load like donkey and run like horse. 2. Hinny: When a male horse and a female donkey mate to produce offspring, a hinny is born. It is infertile. 3. Liger: The hybrid obtained from male lion and female tiger is called liger. It is bigger than their parents and behave like lion. 4. Tigon: The hybrid obtained from male tiger and female lion is called tigon. It is smaller than their parents. They look like tiger but behave mostly like lion. 5. Beefalo: The hybrid obtained from American Bison and bull is called beefalo. They are fertile. It is done for more meat. 6. Zebroid: The hybrid obtained from zebra and horse is called zebroid. They are infertile. 7. Pomato: The hybrid obtained from tomato and potato is called pomato. They give tomatoes outside the soil and potatoes inside the soil. Advantages of cross breeding Cross breeding is used in both animal husbandry and agriculture. Several species are crossed in order to create hybrids with desirable characteristics. The following are some of the most significant advantages of cross breeding. 1. It helps improve the quality of both plants and animals, so farmers can get more out put from their farms. Fig. Mule Fig. Hinny Fact File Mule, and Hinny are infertile. They do not give birth. Fig. Liger Fig. Tigon Fig. Beefalo Fig. Zebroid Fact File The crossing between lemon and orange gives Meyer lemon which is a hybrid. Fig. Pomato Fact File Crossbred dogs live longer than purebred dogs.

Oasis School Science and Technology - 10 115 2. Stronger offspring are produced when local and foreign breeds with desirable characteris are crossed. 3. Cross breeding between two species helps to cancel out weak traits of each species. 4. Animals that have been cross bred are heterotic. Therefore, hybrid organisms possess better and improved biological characteristics. Better weight, height, and adaptability can be found in crossbred animals. Reasonable Fact Farmers go to ICIMOD to crossbreed their goats. Farmers travel to ICIMOD to cross breed their goats because ICIMOD sells high-quality goats. Goats will pass on these superior traits to their progeny. Farmers make a good profit. Activity 3 Observe ten different crossbred dogs. Do they have same traits? Discuss. Beware of dogs. Disadvantages of cross breeding Anyone can perform crossbreeding. We simply need to find a male and female of two different plants or animal species, breeds, or varieties and breed them together. Crossbreeding takes place. It occurs naturally between various organisms without the assistance of humans. Some disadvantages of crossbreeding are: i. Backcrossing to an inferior version of the original breed can result from random cross breeding. ii. Cross-breeding can result in the birth of violent and aggressive offspring, or vice versa. It is challenging to forecast their nature. iii. The adult body size of offspring is extremely difficult to predict. For example, a very large liger is created when a lion and a tiger are crossed. iv. Animals usually die while giving birth because their offspring may have larger heads or bodies inherited from larger male breeds. v. The price in the market for hybrid is comparatively less than pure breeds. vi. Due to continuous cross breeding some pure breeds may extinct. Reasonable Fact A crossbreed may be sterile. A crossbreed have chromosomes from two different species which do not match up, so it does not have viable sex cells, which can not produce sperms and eggs. In Vitro Fertilization (IVF) There are many assisted reproductive technology. Among them in vitro fertilization is most common. It is typically used to treat both male and female infertility. In 1977, Bourne

116 Oasis School Science and Technology - 10 Hall in Cambridge, England, used IVF to treat human infertility for the first time. Generally, in this process, a female provides an ovum, and a male provides sperms. The ovum and sperm are then fertilized in the Petri dish, beaker, or glass tube. The zygote is placed in the uterus where it develops into an embryo. The embryo will now develop into a foetus and continue to grow normally inside the uterus. This technology is called in vitro fertilization. The process in which ovum and sperm are fertilized outside the female body in the glass vessels is called in vitro fertilization. Women who wish to use in vitro fertilization must take ovary-stimulating medications. As a result of sedative, many eggs are released by the stimulated ovary, and these eggs are collected by the doctors. On the same day, the sperms are also collected from male and washed. In a petri dish under suitable circumstances, the ovum and sperm are fertilized. Doctors examine embryos for genetic and medical conditions. It moves to the uterus after a few weeks. Two weeks later, a blood test helps whether the embryo is either growing well or is being rejected. Fig: in vitro fertilization Conditions when doctors suggest in vitro fertilization i. IVF is advised if the fallopian tube is absent or afflicted with incurable diseases. ii. If a woman has endometriosis disease. It is a condition in which additional tissues is developing in the uterus and fallopian tube. iii. If males have an insufficient number of sperms or any other sperm-related defect. iv. If the male is not producing sperms at all, the sperms should be collected surgically. v. If a man or woman has a genetic disorder that prevents conception. Fact File The first IVF baby (Louise Joy Brown) from Lesle Brown and John Brown born on 25 july 1978. Similarly, in Nepal the first IVF baby (Om Mani Tamang) from Rajendra Tamang and Sandhya Tamang born on 3 march 2005. Fact File In vitro fertilization is the most successful fertility treatment currently available.

Oasis School Science and Technology - 10 117 Reasonable Fact Ovary is stimulated using drugs for IVF. Drugs are used to stimulate the ovaries during IVF because doing so makes it easier to collect multiple ova in a syringe otherwise only one ovum is produced at a time. Importance of in vitro fertilization (IVF) 1. It helps infertile couples who are unable to conceive naturally. 2. It is the most effective method of treating infertility. 3. It can assist people in same-sex relationships or single women in becoming parents. 4. It helps in the diagnosis of fertilization issues. 5. If any genetic disorders or diseases are discovered, embryos are genetically tested and destroyed. Disadvantages of in vitro fertilization(IVF) 1. Sometimes IVF doesn't work. It is based on the age of the mother and reproductive history. IVF success rates are higher for the younger woman than the older woman. Compared to women who have never been pregnant, those who have previously given birth have a higher success rate. 2. The probability of miscarriage is between 15 and 25 percent. 3. The success rate of IVF is low in those parents who are taking alcohol and caffeine. 4. Multiple embryos are implanted into the uterus because there is a chance of failure. As a result, people get multiple births. 5. IVF technology is expensive. 6. Some people say it is unethical work. 7. It may give pre-matured and under weight baby. 8. In this process the woman may have psychological stress. Artificial Insemination Artificial insemination (AI) is a type of assisted reproduction. When couples are unable to conceive naturally, it is used to treat infertility. Infertility in humans was first treated with artificial insemination in 1790. In 1884, a donor successfully performed the first artificial insemination procedure. Beginning in the 1950s, there was the first sperm bank. A sperms bank is a place where semen is kept in cold storage for use in artificial insemination. Fig: Artificial insemination

118 Oasis School Science and Technology - 10 The women's menstrual cycle is closely monitored during AI process. The timing of the ovulation cycle is determined using ovulation kits, ultrasound, blood tests, the softness of the cervix's nose, etc. Drugs may occasionally be used to initiate the menstrual cycle. When a healthy man abstains for at least three days, his sperms are collected. Sperms are not collected if the husband or the sperms donor is ill. When sperm is donated privately, it is not kept or frozen. It is given to the woman freshly. Artificial insemination refers to the meaningful implantation of sperms into a female's cervix or uterus. When unwashed raw sperms or sperms donated by a sperms bank are inserted into the vagina, this is known as intracervical insemination. It is the easiest form of artificial insemination. It can be performed by the woman herself. In fertility clinics, however, doctors will first introduce it to the vagina. The sperm will then travel through the cervix and into the uterus. It will continue to move deeper into the fallopian tubes, fertilizing the egg. For about 30 minutes, women should remain motionless to allow the sperm to swim easily toward the egg. Intrauterine insemination occurs when washed sperm is introduced directly into the uterus. It is more effective than intracervical insemination. To increase the success rate, washed sperm is sometimes introduced into the fallopian tubes. Condition for artificial insemination Conditions when doctors suggest artificial insemination are: i. If the woman has endometriosis. ii. If there are not enough sperm in the man. iii. If there is less sperm mobility in the semen. iv. If sperm are unable to enter the cervix. Advantages of artificial insemination i. It is cheaper than in vitro fertilization. ii. It helps a woman to conceive if she is not conceiving naturally. ii. It helps single women, widowers, lesbians etc. to be a parent. iv. It helps a man to be a parent in case his sperm count is low. v. In animal husbandry, it does not require to keep male in the farm. vi. It reduces STD and increases rate of fertility. vii. It avoids injury which frequently occurs during male and female coupling. Fact File If a woman under the age of 35 fails to conceive after a year of unprotected mating, her doctor may recommend artificial insemination. Fig: intracervical insemination

Oasis School Science and Technology - 10 119 Reasonable Fact How does artificial insemination help farmers? In animal husbandry, it does not require to keep male in the farm. It reduces cost. It reduces STD and increases rate of fertility. It avoids injury which frequently occurs during male and female coupling. We can carry sperms for a long distance too. Disadvantages of artificial insemination i. It can be unsuccessful. ii. It needs skilled manpower to do it. iii. Dirty instruments can cause infection. iv. To prepare artificial insemination, it needs more time than natural fertilization. Reasonable Thinking Skill Reasonable Thinking Skill R T S 1. Rita does not want to get married but wants to be a mother. She is considering conceiving through artificial insemination? Explain the risk of artificial insemination to her. Rita does not want to get married but wants to be a mother. She has consulted doctors about artificial insemination. There are certain risks of artificial insemination. They are: i. Artificial insemination can fail. ii. It can transfer diseases. iii. Infected tools can cause uterine infection or cancer. 2. Mrs Krishna Kumari has a healthy and big buffalo that gives lots of milk. She wants to breed siblings he-buffalo and she-buffalo so that the good traits can be transferred to the offspring. Did she make the right decision? Explain to her why is it a wrong idea. Also, explain to her that she should find a healthy he-buffalo which is not related to her she-buffalo with reasons. Mrs Krishna Kumari has a healthy and big buffalo that gives lots of milk. She plans to breed sibling he-buffalo and she-buffalo so that good traits can be transferred to the offspring. However, it is not a good idea. We should tell her that breeding two siblings are called inbreeding. Inbreeding causes recessive characteristics to appear in organisms. Offsprings can be weak, prone to diseases and cannot adapt to changing environments. Instead, she should practise line breeding. It means finding a healthy he-buffalo which is separated for a few generations. It can be a distant cousin. It contains more gene pools. So, offsprings can have better genetic make up and physical traits. Outbreeding is also a good solution to her problem. It means finding a healthy hebuffalo which is not genetically related to her buffalo. It provides a wide range of gene pools. The offsprings will be in better health, can adapt easily to the environment and has lots of good traits. 3. Rohan is an infertile man. He has already tried ayurvedic medicines. He has also prayed and visited wizards. But still has no child. What suggestions can we offer him so that he can father some children? Despite using many ayurvedic medicines, herbs or visiting wizards, praying etc. Ram

120 Oasis School Science and Technology - 10 still does not have a child. It could be because of low sperm count or immotile sperm. We should suggest him to use assisted reproductive technology. i. He can use artificial insemination. Doctors will collect sperm. Sperm will be washed, concentrated and introduced into the cervix of his wife. Sperm will swim to the uterus and fertilize with the ovum. ii. If intracervical insemination fails, doctors will introduce washed sperm directly into the uterus or fallopian tube to increase the probability of fertilization. iii. If artificial insemination fails, he can try in vitro fertilization. Doctors will collect his sperm and ovum from his wife. It is fertilized in a petri dish. Healthy embryos are installed in the uterus of his wife. 4. Compare between inbreeding and cross-breeding. The comparison between inbreeding and cross-breeding are: SN Inbreeding SN Crossbreeding 1. Breeding between males and females who are genetically closely related to one another is known as inbreeding. 1. Crossbreeding is the process of mating two purebred individuals from different species, breeds, or varieties to create new offspring. 2. Generally, inbreeding is harmful. 2. Generally, crossbreeding is useful. 3. Inbreeding decreases the gene pool. 3. Crossbreeding increases the gene pool. 4. It brings out the recessive characteristics in organisms. 4. It brings out lots of variation in organisms. 5. Offsprings born by outbreeding can adapt better to the environment. Outcrossing means crossing between two organisms that are genetically separated by lots of generations. It brings lots of varieties of genes to the gene pool. New offsprings can select among the best genes. It brings various adaptational features to the organism. So, they can survive better in the environment. 6. Farmers try to avoid inbreeding. What might be the reasons? Farmers try to avoid inbreeding, especially in animals because of the following reasons: i. Offspring from inbreeding is usually violent. ii. Most offspring die early. iii. Most of them are sick. iv. They have lots of recessive characters. 7. If two cattle from the same parents bred together, what is it called? If two cattle from the same mother are bred together, it is called inbreeding. 8. Compare between a tigon and a lion. The comparison between a tigon and a lion are: SN Tigon SN Lion 1. It is crossbred. 1. It is not cross bred. 2. It is sterile. 2. It is fertile.

Oasis School Science and Technology - 10 121 9. We should be very careful while collecting a sample for the DNA test. We should be very careful while collecting a sample for a DNA test so that we could collect sufficient DNA for the test. We should also be aware that we should not mix samples from other sources than the required ones. 10. A child was born from a rape victim. How can the father of the child be identified? A child from a rape case, or a child who does not know his biological parent can track the parents from DNA testing. DNA testing can accurately track down the parents. Exercises 1. Select the best answer from the given alternatives. a. What are genes made of? i. vitamins ii. DNA sequence iii. cellulose iv. chitin b. How can we change fruit into a vaccine? i. injecting vaccines in fruit and distributing them in the market. ii. dissolving vaccine in fruit. iii. inserting virus genes in seeds and using that seed to grow plants. iv. using compost fertilizer to grow fruits. c. Which assisted reproductive technology is popular in animal husbandry? i. in vitro fertilization ii. intracervical insemination iii. insemination by bull iv. artificial fertilization d. In which assisted reproductive technology, an embryo is formed in a Petri dish? i. internal fertilization ii. external fertilization iii. artificial insemination iv. in vitro fertilization e. Pet shops cross different purebred dogs to produce new puppies. What kind of animals are they? i. purebreds ii. crossbreds iii. hybrids iv. clones f. How are mules born? i. from the male mule and female mule ii. cross-breeding between a female donkey and a male horse iii. cross-breeding between a male donkey and a female horse iv. from crossbreeding of mole and horse

122 Oasis School Science and Technology - 10 2. Define the following terms with required examples. a. Genes and genetics b. Genetic engineer c. Genetic technology d. DNA testing e. Reproduction f. Breeding g. Selective breeding h. Inbreeding i. Line breeding j. Outcrossing k. Purebred l. Crossbreds m. In vitro fertilization n. Artificial insemination o. Intracervical insemination p. Intrauterine insemination 3. Answer the following questions in very short. a. What are the primary contents of the vaccine? b. Can DNA testing identify the gender of the person? c. In which assisted reproductive technology, the zygote is introduced in a fallopian tube? d. If a Holstein cow is bred with a Siri cow, what type of breeding is it? e. What is the breeding between two different species or breeds called? 4. Give reasons. a. Genes are the smallest hereditary unit. b. It would be wise to test the DNA of babies before they are born. c. Scientists add genomes of viruses in seeds of plants. d. Experimenting on human genomes is illegal. e. Study of genes is very important in genetic engineering. f. Most hybrid animals are infertile. g. DNA testing can help in the criminal investigation. h. Selective breeding is popular in the pet industry. i. Farmers should practice line breeding than inbreeding. j. Drugs are used during in vitro fertilization. 5. Differentiate between the following. a. Inbreeding and line-breeding b. Cross breeding and outbreeding c. Pure bred and crossbred d. Artificial insemination and in vitro fertilization e. In vitro fertilization and intracervical insemination f. Zebra and zebroid 6. Answer the following questions in short. a. What kind of physical properties of an organism are determined by genes? b. What kind of measures have different countries adopted against genetic technology?

Oasis School Science and Technology - 10 123 c. Why is DNA testing growing popular? Can DNA testing be used to solve criminal activities? How is it used? d. What kind of genetic technology is used in medicine? e. Do selective breeding help in organic evolution? How? f. What are the advantages of line breeding? g. What are the conditions under which a couple is suggested to use artificial insemination? h. Is genetic engineering a boon or curse? Put forward your opinion. 7. Answer the following questions on the basis of the given figure. i. Which assisted reproductive technology is shown in the diagram? ii. Why is sperm washed for this? iii. Why is DNA testing of embryos important? iv. Why are multiple embryos put in the uterus? 8. Answer the following long questions. a. How has genetic technology helped human civilization? Discuss its importance. b. How is the DNA test done? What is the application of DNA testing? c. Do genetic technology have any disadvantages? If there are any, enlist them. d. DNA testing is very helpful in agriculture. How? e. What is cross-breeding? How is it good for farmers? Enlist some of its disadvantages. f. How is in vitro fertilization performed? Why is it a boon for infertile couples? g. Explain the procedure for artificial insemination. h. How has artificial insemination helped farmers? Discuss. i. A married couple engaged in unprotected mating for more than a year already but they could not conceive. What could be the problems? Discuss. j. Despite trying for many years, Mr. and Mrs. Chandra are not able to make a child. Whom should they consult now? What is the probable solution to their problems? k. What is selective breeding? Discuss the methods of selective breeding.

124 Oasis School Science and Technology - 10 Key terms and terminologies 1. Circulatory system: The organ system in human body which supplies food, oxygen, hormone, etc. to the different parts of the body and carries away metabolic wastes to the site of excretion with the help of blood is called blood circulatory system. 2. Blood : Blood is a heterogeneous, red-coloured, viscous liquid connective tissue that is made up of 55% plasma and 45% blood cells. 3. Plasma : Plasma is a transparent clear yellowish liquid. It forms about 55% of the blood volume. 4. Erythrocytes (RBCs): Erythrocytes (RBCs) are red coloured, biconcave and enucleated, disc-like structures present in the plasma. 5. Haemoglobin : Haemoglobin is a red-colored respiratory pigment. It is made up of an iron-containing pigment called haemin and a protein called globin. 6. Anaemia : When there is a long-term decrease in the number of RBCs or UNIT 5 PHYSIOLOGICAL STRUCTURE AND LIFE PROCESS Estimated teaching periods Theory 9 Practical 3 • Introduction to the human blood circulatory system • Structure and function of different parts of human blood circulatory system • Blood circulatory system in human body • Introduction and identification of blood group • Investigation of heartbeat and pulse • Blood pressure, blood sugar and uric acid • Heart attack: introduction, causes, measures to control and curative method (angiography and bypass surgery) The Sequence of Curriculum Issued by CDC Karl Landsteiner is well known as the father of transfusion medicine for his research onthe blood group system. He was born in AustriaHungary on 14th June 1868 and died on 26th June 1943. He was a biologist, physician and immunologist. He distinguished main blood groups in 1900. He also discovered the Rhesus factor in RBC. He also discovered the polio virus. He was honoured with Nobel Prize in Physiology or Medicine in 1930. About the Scientist Karl Landsteiner

Oasis School Science and Technology - 10 125 in the amount of haemoglobin or in both, the condition is called anaemia. 7. WBCs : White blood corpuscles (WBCs), or leucocytes, are larger and irregular cells having a nucleus. 8. Leukaemia : Leukaemia is a condition in which a person has excess number of WBCs in their body. 9. Leucopenia : Leucopenia is a condition in which there is a decrease in the WBC count below 4000 per mm3 . 10. Thrombocytes : Thrombocytes are colourless, oval or round, non-nucleated cytoplasmic fragments formed from giant cells of the bone marrow. 11. Haemophilia : It is a genetic disease, in which the blood loses its ability to clot. 12. Blood-clotting : The process of formation of solid mesh at the site of cuts and wounds is called blood-clotting or blood coagulation. 13. Pericardium : The human heart remains enclosed in a double layered membranous sac called pericardium. 14. Pericardial fluid : The space between two pericardial layers is filled with a slippery fluid known as pericardial fluid. 15. Tricuspid valve : The valve between the right auricle and right ventricle is called tricuspid valve. 16. Bicuspid valve : The valve present between left auricle and the left ventricle is called bicuspid valve. 17. Pulmonary valve : The valve present between pulmonary artery and right ventricle is known as pulmonary valve. 18. Aortic valve : The valve present between aorta and the left ventricle is known as the aortic valve. 19. Blood vessels : Blood vessels are the tubes or pipes through which blood flows. 20. Arteries : Arteries are thick-walled blood vessels that carry blood away from the heart to different parts of the body. 21. Veins : Veins are thin-walled blood vessels that carry blood towards the heart. 22. Capillaries : Capillaries are microscopic, extremely narrow and thin-walled blood vessels which can penetrate every part of the body. 23. Double circulation : The circulation in which blood travels twice through the heart in one complete cycle in the body is called double circulation. 24. Systemic circulation: The circulation of blood from the left ventricle to the right auricle of the heart via body tissues (except lungs) is called systemic circulation. 25. Pulmonary circulation: The circulation of blood from the right ventricle of the heart to the left auricle via lungs is called pulmonary circulation. 26. Blood pressure : Blood pressure is the force with which blood pushes against the walls of the arteries. 27. Systolic blood pressure: Systolic blood pressure is the measure of maximum pressure in the arteries when left ventricle contracts. 28. Diastolic blood pressure: Diastolic blood pressure is the measure of minimum pressure in the arteries when left ventricle relaxes. 29. Heart beat : The continuous rhythmic beat throughout life which is produced due to contraction and relaxation of the heart muscles is called heart beat.

126 Oasis School Science and Technology - 10 30. Arterial pulse : Arterial pulse is the systemic contraction of the heart that can be felt as a jerk in certain arteries which are superficial in position. 31. Diabetes : Diabetes is a disease which is caused due to increase in the sugar level in blood. It occurs due to lack of insulin hormone. 32. Uric acid : Uric acid is an antioxidant which helps to remove toxic materials from our body and also protects the inner walls of the blood vessels. 33. Gout (uric acid) : Gout is a form of arthritic disease which is characterized by the deposition of uric acid crystals in the large joints of body like knee, toe, etc. 34. Heart attack : The blockage of the flow of pure blood into the cardiac tissues of the heart is called a heart attack. 35. Angiography : Angiography is an effective way to treat a heart attack. It uses an x-ray imaging technique to find the blood clot. After that mesh tube and a tiny balloon is used to open the blockage. 36. Bypass surgery : Bypass surgery means finding alternative arteries to supply blood to the cardiac tissue of the heart when the majority of blood vessels are blocked or are very narrow. Human Blood Circulatory System It is important for the human body to get oxygen, nutrients, hormones, etc. to different tissues rapidly and get rid of waste quickly. So, the blood circulatory system is a very important part of the body. It is an organ system in the human body responsible for transporting various materials inside the body with the help of blood. The blood circulatory system in human body consists of three main parts: (i)Blood (circulatory medium) (ii) System of blood vessels (arteries, veins and capillaries) and (iii) Heart (pumping organ). The circulatory system gives food and oxygen to the cells of the body so that they can live. It removes carbon dioxide and other waste products from the cells. This system transports various substances to - and - fro between different tissues of the body. It also helps to maintain a balanced chemical composition in the body. This system is also responsible for maintaining constant body temperature. In addition to the blood circulatory system, for the transport of blood in human beings, there is another system called the lymphatic system. Thus, the organ system in human body which supplies food, oxygen, hormone, etc. to the different parts of the body and carries away metabolic wastes to the site of excretion with the help of blood is called blood circulatory system. In the blood circulatory system, the heart acts as a pumping organ. The arteries, veins and capillaries act as tubes through which blood flows and the blood itself acts as a circulatory medium. Main Functions of Circulatory System 1. It transports oxygen, digested food materials and hormones to various parts of the body. 2. It transports waste materials produced in various tissues/organs for their elimination from the body. 3. It regulates the body temperature, water and mineral content of the body.

Oasis School Science and Technology - 10 127 Blood Blood is a heterogeneous, red-coloured, viscous liquid connective tissue that is made up of 55% plasma and 45% blood cells. The human body contains about 4.8 to 5.8 liters of blood. The blood constitutes about 1 30 part of the body's weight. The composition of human blood is given below: Blood Plasma Blood corpuscles Red blood corpuscles White blood corpuscles Blood platelets 55% 45% (RBC or erythrocytes) (WBC or leucocytes) (Thrombocytes) Properties of blood 1. Blood is a red, viscous and complex fluid connective tissue. 2. It is salty in taste and slightly alkaline in nature with a pH range of 7.3 to 7.5. 3. The specific gravity of blood is 1.05 to 1.06. Composition of Blood Blood contains three types of cellular elements: (i) Red blood corpuscles, (ii) White blood corpuscles and (iii) Platelets that move about in a clear yellowish fluid called plasma. The plasma occupies about 55% and cellular elements (blood corpuscles) occupy about 45% of the blood by volume. Fact File • Blood constitutes about 1/30 of the body weight. • Blood is alkaline in nature but salty in taste. Blood film under a compound microscope Plasma Red blood cell White blood cell Platelet Plasma Plasma is a transparent clear yellowish liquid. It forms about 55% of the blood volume. Plasma contains about 90% water, 8% proteins (albumin, globulin and fibrinogen) and

128 Oasis School Science and Technology - 10 2% other dissolved substances like minerals, carbohydrates, salts, antibodies, hormones, respiratory gases and waste products. Plasma transports all these dissolved substances from one part of the body to another. Red blood cells, white blood cells and platelets are immersed in the plasma. Functions of Plasma 1. Plasma transports digested food to different parts of the body. 2. It transports waste materials like carbon dioxide, urea, etc. to their respective sites for excretion. 3. It regulates the body temperature, amount of water and other chemicals in the body. 4. It transports hormones secreted by the endocrine glands to various parts of the body. 5. Fibrinogen present in plasma plays an important role in blood clotting. Red blood cells or Erythrocytes Erythrocytes (RBCs) are red colored (erythrosred), biconcave and enucleated (without nucleus) disc-like structures present in the plasma. They are thick and rounded at the peripheral region and flat in the center. Erythrocytes are very small in size (about 7 µ in diameter). An erythrocyte is bound by an elastic and a semi-permeable plasma membrane. Red blood cells appear red due to the presence of haemoglobin, i.e. iron-containing pigment. Reasonable Fact Blood is called a heterogeneous mixture, why? Blood is called a heterogeneous mixture because the blood plasma contains bigger-sized blood corpuscles. Why is blood red in colour? Blood is red in colour due to the presence of red pigment called haemoglobin. Blood without RBCs has light yellow colour, why? In absence of RBCs, blood has only WBCs, platelets and blood plasma. The blood plasma comprises about 55% of the total blood. It is a transparent yellow liquid. Therefore, blood without WBCs has light yellow colour. Red blood cells are produced in the bone marrow of bones such as ribs, vertebrae and skull bones. The average life span of red blood cells is about 120 days. They are destroyed in the liver. The number of RBCs ranges from 5 – 5.5 million per cubic millimeter in an adult man and 4.5 – 5 million per cubic millimeter in an adult woman. Fig. Red blood cells

Oasis School Science and Technology - 10 129 Note: In infants, the count of RBCs is 6–7 million / mm3 whereas in a foetus it is 7.8 million / mm3 . In the first ten days of the post natal life, a large number of RBCs are destroyed. This is one of the causes of jaundice in a new born. Polycythemia is a disease caused by excessive quantity of RBCs. Functions of Erythrocytes (RBCs) 1. Erythrocytes transport oxygen from the lungs to the tissues and carbon dioxide from the tissues to the lungs. 2. Erythrocytes maintain the viscosity of blood and ion-balance. Haemoglobin Haemoglobin is a red-colored respiratory pigment. It is made up of an iron-containing pigment called haemin (4%) and a protein called globin (96%). The iron content of haemoglobin is about 0.34%, and about 3 g of iron is present as haemoglobin in the total blood of an adult. Haemoglobin combines with oxygen and forms oxyhaemoglobin. Similarly, it combines with carbon dioxide and forms carboxyhaemoglobin. Functions 1. Haemoglobin plays an important role in oxygen and carbon dioxide transport. 2. It helps to balance the acid-base balance of the blood. Anaemia When there is a long-term decrease in the number of RBCs or in the amount of haemoglobin or in both, the condition is called anaemia. It is mainly caused due to malnutrition. The major symptoms of anaemia are as follows: i. Loss in weight ii. Loss in appetite iii. Slow and retarded growth iv. Pale and dull-colored skin Reasonable Fact A person suffering from anaemia feels tired after walking for a short period. A person suffering from anaemia has deficiency of red blood cells, or haemoglobin in his/her blood. So, adequate amount of oxygen cannot be supplied to the body to release energy. As a result, a person suffering from anaemia feels tired after walking for a short period. White blood cells or Leucocytes White blood corpuscles (WBCs), or leucocytes, are larger (8 – 15 µ in diameter) and irregular cells having a nucleus. They are capable of amoeboid movement. Leucocytes are of two types: granulocytes (having granules in their cytoplasm and lobed nucleus) and agranulocytes (without granules in their cytoplasm and unilobed nucleus). Neutrophils, eosinophils and basophils are granulocytes whereas monocytes and lymphocytes are agranulocytes.

130 Oasis School Science and Technology - 10 Neutrophil Eosinophil Lymphocyte Monocyte Basophil Fig. Various types of leucocytes (WBCs) Leucocytes (WBCs) are produced by the stem cells in the red bone marrow and lymph nodes. The average total number of WBCs is 4000 - 11000 per cubic millimeter. They live for a few hours to almost 2 weeks. They are destroyed in the liver, spleen and at the site of infection. Functions of WBCs 1. WBCs help in destroying solid substances like bacteria by engulfing them, and hence they defend the body from various diseases. 2. They fight against germs (microbes) and destroy the damaged cells by phagocytosis. 3. They also help in the formation of antibodies, which neutralize or kill the germs that enter the body. Leukaemia and Leucopenia Leukaemia is a malignant disease of one or more variety of leucocytes, the number of which are greatly increased. It is caused due to enormous increase in the WBCs at the cost of RBCs. This condition is also called blood cancer. Leucopenia is a condition in which there is a decrease in the WBC count below 4000 per mm3 . It is caused due to the fall in neutrophil cells. Reasonable Fact White blood cells are called soldiers of the body. Ans: White blood cells protect the body from the attack of disease causing germs (pathogens) and other harmful foreign materials. Therefore, white blood cells are called soldiers of the body. Thrombocytes or Platelets Thrombocytes are colourless, oval or round, non-nucleated cytoplasmic fragments formed Fact File WBCs are the largest blood corpuscles whereas platelets are the smallest.

Oasis School Science and Technology - 10 131 from giant cells of the bone marrow. They are found floating in the plasma. The number of platelets varies from 2.5 lakh to 4.5 lakh per cubic millimeter. The average diameter of platelets is about 2.5 µ. They live for about 8 to 9 days and are destroyed in the spleen. Function of thrombocytes Thrombocytes play an important role in the coagulation or clotting of blood. They release a chemical called thromboplastin, which initiates the process of clotting the blood. Reasonable Fact Blood does not clot when inside the blood vessels due to the presence of a strong, natural anticoagulant called heparin or antiprothrombin produced in the liver. But when platelets come in contact with the environment, they burst and liberate thromboplastin, which helps in the formation of an enzyme prothrombinase. This enzyme inactivates heparin and it converts inactive prothrombin into its active form, thrombin. Therefore, blood clots only when it escapes the blood vessels but does not clot inside the blood vessels. Activity 1 To study the blood film under a compound microscope • Clean a finger tip of your friend with a spirit swab. • Prick the fingertip with a sterilized lancet. Don’t use that lancet to prick another finger tip as it may transmit dangerous diseases. • Put a drop of blood on a one end of a slide, spread it throughout the slide by using another slide and allow it to dry. • Put a few drops of Leishman’s stain on it and dry it for a few minutes. • Wash the slide with distilled water and observe it under a compound microscope. • Draw a neat and labeled figure and prepare a short report. Haemophilia It is a genetic disease in which the blood loses its ability to clot, leading to slow and persistent bleeding. It is a sex-linked recessive disease found in males. The females are carriers of this disease. Clotting of blood The blood, when exposed to air, changes into a jelly-like mass as a result of a series of changes. This process of solidification of blood is called clotting or coagulation of blood. The clotting time of blood is normally 4 to 10 minutes.

132 Oasis School Science and Technology - 10 Table: Various types of blood cells, their number and life span Name of blood cells No. in 1mm3 volume of blood Life span 1. Erythrocytes or RBCs 4.5 – 5.5 million 120 days 2. Leucocytes or WBCs 4000 – 11000 Few hours to few days a. Granulocytes 1–4 days i. Eosinophils 60 – 300 8 – 12 days ii. Neutrophils 4000 – 5000 6 hours to a few days iii. Basophils 35 – 100 Few hours to few days b. Agranulocytes Few months i. Lymphocytes 1500 – 2000 Few hours to years ii. Monocytes 200 – 700 Few months 3. Thrombocytes or Platelets 250000 to 400000 8 to 9 days Functions of Blood i. Transport of respiratory gases: Blood transports oxygen from the lungs to the tissues and carbon dioxide from the tissues to the lungs. ii. Transport of nutrients: The digested food materials are absorbed by blood at the site of absorption (intestine) and transported to various parts of the body. iii. Transport of waste products: The metabolic waste materials produced in the body are transported by blood to the organs meant for their removal from the body. iv. Transport of body secretions: Blood transports chemical secretions like hormones from the site of their secretion to the targeted organ. v. Regulation of body temperature: Blood helps to regulate the body temperature. vi. Defense against infection: WBCs present in blood help to prevent the body against infection. vii. Prevention of blood loss: Prothrombin and fibrinogen proteins present in platelets and plasma help in blood clotting at the site of injury. This prevents the loss of blood. viii. Water balance: Blood maintains water balance in the body to a constant level. Blood groups According to Karl Landsteiner (1900 AD), a German biochemist, there are two types of proteins: Agglutinogen or antigen, and Agglutinin, or antibody; two types of antigens: A and B; and two types of antibodies: a and b, in the human blood. Antigen A and antibody a are incompatible and antagonistic, and cause self clumping. Similarly, antigen B and antibody b are incompatible and cause self clumping. On the basis of the aforementioned facts, a system of blood groups called the ABO system

Oasis School Science and Technology - 10 133 having four blood groups is recognized in the human blood. These blood groups are : A, B, AB and O. The given table shows human blood groups and their compatibility. Blood groups Antigens of RBCs Antibodies in Plasma Can donate blood to Can receive blood from A A b A, AB A, O B B a B, AB B, O AB AB None AB A, B, AB, O O None a, b A, B, AB, O O From the above table, it is clear that blood group O can be given to a person with blood group O, A, B or AB. So, persons having blood group O are called universal donors. Similarly, persons with blood group AB can receive blood from A, B, AB or O blood group as their blood lacks antibodies in their plasma. So, persons with blood group AB are called universal recipients. The antigens present in the donor's blood can react with antibodies present in the recipient's blood and cause clumping or agglutination of RBCs. Therefore, knowledge of blood groups is essential for safe transfusion so that the antigen of the donor's blood matches with the antibodies of the recipient's blood. Rhesus antigen (Rh – Factor) Depending upon the type of race, the surface of human RBCs contains a protein i.e., Rh antigen (Landsteiner and Wiener, 1940 AD). This antigen is also found in the RBCs of Rhesus monkeys. Therefore, it is called Rh - Factor. In Black Africans, 100 percent population has Rh - antigen and they are called Rh+. In Black Americans, about 95% are Rh+ and 5% are Rh–. Depending upon the type of race, 85 – 99% of the white population is Rh+ and remaining population is Rh–. Both Rh+ and Rh– persons are quite normal. But the problem arises when Rh+ blood comes in contact with Rh– blood, either due to blood transfusion or during pregnancy. Rh– blood can be given safely to a person with Rh+ blood. When Rh– blood is transfused into Rh+ person, the recipient forms antibodies in his/her body. However, no complications develop after the first transfusion. In case of a second transfusion of Rh+ blood to an Rh– person, the latter's anti Rh factors attack and destroy the donor's RBC. A serious problem arises if an Rh– mother is carrying a Rh+ foetus. The Rh+ blood of the foetus stimulates the formation of anti- Rh factors in the mother's blood. During the first pregnancy, enough antibodies are not produced to harm the foetus. But during the second pregnancy, if the foetus is Rh+, a large number of RBCs of the foetus are destroyed by anti Rh factors of the mother, which may damage the child's brain. Importance of blood groups in blood donation When it comes to blood donations, it is important to know about the different types of blood groups. If patient gets blood that does not match to his blood group, patient immune system could attack the donated blood. There may occur intravenous blood clotting. This can lead to a dangerous or even life-threatening transfusion reaction.

134 Oasis School Science and Technology - 10 Heart: Location, Shape and Size The human heart lies near the middle of the thoracic cavity, between the two lungs. Twothird of the heart is located in the left side of the thorax whereas one-third is located in the right side. The heart is a hollow, conical organ made up of cardiac muscles. It is about the size of a fist of the owner. It measures about 12 cm in length and 9 cm in breadth. The average weight of the heart is about 300 grams in adults. External Morphology The human heart contains four complete chambers. It is divided into two halves (right half and left half) by septa. Each half consists of two chambers: the upper, small-sized atrium or auricle and the lower, large-sized ventricle. The human heart remains enclosed in a double layered membranous sac called pericardium. The space between two pericardial layers is filled with a slippery fluid known as pericardial fluid. This fluid enables the heart to contract smoothly, keeps tissues of the heart moist for proper beating and also protects the heart from mechanical injury. The atria (auricles) are demarcated externally from the ventricles by an irregular groove called coronary sulcus. The atria form the upper smaller part of the heart whereas the ventricles form the lower larger part. Two ventricles are demarcated externally from one another by an oblique groove called interventricular sulcus which contains coronary blood vessels. Various blood vessels entering and leaving the heart can be seen externally. Internal Morphology The longitudinal cross-section of the human heart shows two upper chambers called auricles, two lower chambers called ventricles, great blood vessels entering and leaving the heart, various apertures and valves. The atria (right atrium and left atrium) are thin-walled chambers which are separated from each other by a muscular wall called inter-auricular septum. The ventricles are thickwalled chambers which are separated by a thick muscular wall called inter-ventricular septum. The thickness of the walls in different chambers reflects their functions. The auricles are thinly muscled as they pump blood to only short distances to the ventricles. The wall of the right ventricle is more muscular than that of the auricles because it has to pump blood to a much farther distance to the lungs. Similarly, the left ventricle has the thickest wall as it has to force the blood all the way round the body. Fig. External structure of human heart Aorta Pulmonary artery Pulmonary veins Left auricle Left ventricle Pericardium Inferior vena cava Right ventricle Right auricle Pulmonary veins Superior vena cava

Oasis School Science and Technology - 10 135 Fig. Internal structure of human heart Superior vena cava Pulmonary artery Right auricle Aorta Pulmonary artery Pulmonary veins Left auricle Pulmonary valve Aortic valve Left ventricle Septum Cardiac muscle Pulmonary veins Tricuspid valve Right ventricle Inferior vena cava Bicuspid/mitral valve Various blood vessels enter and leave the heart. Three blood vessels are connected to the right atrium. The superior vena cava brings deoxygenated blood from the upper region, i.e. head, neck and upper limbs of the body whereas the inferior vena cava brings deoxygenated blood from the lower region of the body. Similarly, coronary sinus brings deoxygenated blood from the heart's wall. The left auricle is connected to two pairs of pulmonary veins, one pair from each lung. Pulmonary veins bring oxygenated blood from the lungs to the left auricle. Pulmonary aorta arises from the right ventricle and it transports deoxygenated blood to the lungs for purification. Similarly, systemic aorta arises from the left ventricle and transports oxygenated blood to various parts of the body except the lungs. Four different types of valves are present in the human heart which regulate the flow of blood within the heart and its passage. Two valves separate the auricles from the ventricles. They are known as auriculoventricular valves. The tricuspid valve having three concentric flaps is present between the right auricle and right ventricle whereas the bicuspid or mitral valve is present between the left auricle and left ventricle. It has two concentric flaps. Auriculoventricular valves allow the flow of blood from the auricles to ventricles and prevent the back flow. Similarly, the aortic semilunar valve is present at the base of the aorta and the pulmonary semilunar valve is present at the base of the pulmonary artery. Each semilunar valve contains three flaps, shaped like a half moon. Activity 2 To study the external and internal morphology of the mammalian heart • Visit a butcher’s shop and buy a heart of a goat. • Keep the heart in a dissecting tray, observe its external morphology and draw a neat and labeled figure. • Cut open the heart longitudinally and observe the internal parts carefully. • Draw a neat and labeled figure showing the internal structure of the heart.

136 Oasis School Science and Technology - 10 Reasonable Fact The wall of the left ventricle is thicker than that of the right ventricle. The left ventricle pumps out a large amount of blood to different parts of the body through the aorta. For this, a great force is required, which is provided by its thick walls but the right ventricle supplies blood only towards the lungs, which requires less force. Therefore, the wall of the left ventricle is thicker than that of the right ventricle. Reasonable Fact The wall of the right ventricle is thicker than that of the right auricle. The right ventricle pumps blood into the pulmonary artery forcibly whereas the right auricle does not pump blood into the arteries. Hence, the wall of the right ventricle is thicker than that of the right auricle. Reasonable Fact The right auricle is larger than the left auricle. In the right auricle, impure blood of the whole body is poured through the superior venacava and inferior vena cava whereas pure blood is poured into the left auricle from the lungs through the pulmonary veins. Since a larger volume of blood is collected in the right auricle than that of the left auricle, the right auricle is larger than the left auricle. Blood Vessels Blood vessels are the tubes or pipes through which blood flows. They form a system of channels for blood circulation. There are three types of blood vessels, viz. arteries, veins and capillaries. i) Arteries Arteries are thick-walled blood vessels that carry blood away from the heart to different parts of the body. All arteries carry oxygenated blood except the pulmonary artery, which carries deoxygenated blood from the heart to the lungs. An artery has a narrow lumen whereas the wall is thick and elastic. The wall of the artery is made up of three layers – the innermost tunica interna made up of thin and smooth cells, the middle tunica media made up of the muscle and the outermost tunica externa made up of elastic tissue. The branches of arteries are called arterioles. Fig.Detailed structure of an artery Tunica externa Tunica media Tunica interna

Oasis School Science and Technology - 10 137 Arteries are deep seated in the muscle and can bear great pressure. Valves are absent in the arteries except at their origin in the heart. Inside the arteries, blood flows at high speed and under high pressure. The aorta and pulmonary arteries are two main arteries of the human body. ii) Veins Veins are thin-walled blood vessels that carry blood towards the heart. All veins carry deoxygenated blood except the pulmonary veins, which carry oxygenated blood from the lungs to the left auricle. The wall of a vein also contains three layers as in the arteries, however, they are thinner as compared to the arterial wall. Veins are comparatively superficial in position and cannot bear a great pressure. The branches of veins are called venules. Veins are provided with semi-lunar valves at regular intervals in them. These valves open towards the heart to stop the reverse flow of blood as the blood moves against gravity and under low pressure. The lumen of the veins is much wider than that of the arteries through which blood flows easily at low speed and under low pressure. iii) Capillaries Capillaries are microscopic, extremely narrow and thin-walled blood vessels which can penetrate every part of the body. They connect arterioles to the venules. The wall of a capillary is made up of a single layer of endothelium in which tunica media and tunica externa are absent. Fig. Structure of a capillary Fig. Showing capillaries and their network Tunica interna Artery Arteriole Capillary network Venule Vein The exchange of various materials like oxygen, digested food, carbon dioxide and waste materials between the blood and body cells takes place through capillaries. Tunica externa Valve Tunica media Tunica interna Fig. Detailed structure of a vein

138 Oasis School Science and Technology - 10 Differences between Arteries and Veins S.N. Arteries S.N. Veins 1. Arteries carry blood away from the heart. 1. Veins bring blood towards the heart. 2. They are located deep in the body away from the skin. 2. They are located close to the skin. 3. They have narrow lumen and no internal valves. 3. They have wide lumen and have internal valves. 4. Their wall is thick and strong. 4. Their wall is thin and weak. 5. All arteries carry oxygenated blood except pulmonary artery. 5. All veins carry deoxygenated blood except pulmonary veins. Reasonable Fact Veins have valves at intervals in their inner lining whereas arteries do not have valves. Inside the veins blood flows at low speed and under low pressure. So valves are present in the veins at intervals to prevent the backflow of blood. But inside the arteries, blood flows at high speed and under high pressure. So valves are absent in the arteries, as there is no chance of backflow of blood. Reasonable Fact The wall of the artery is made up of thick muscles. Inside arteries, blood flows at high speed and under high pressure. To bear the great pressure, the wall of the arteries is made up of thick muscles. Reasonable Fact Explain why the wall of the artery is thicker than that of the veins. In the arteries, blood flows at a high speed and under high pressure. This may cause bursting of the arteries. Therefore, walls of artery is thicker than that of the veins. Blood Circulation in Human Body In human beings, blood flows twice through the heart before the oxygenated blood is pumped to the body. Such circulation of the blood is called double circulation. In this process, the blood, before going to the general circulation round the body, enters the heart twice, first as deoxygenated blood and then as oxygenated blood. The circulation in which blood travels twice through the heart in one complete cycle in the body is called double circulation.

Oasis School Science and Technology - 10 139 Fig. Process of blood circulation in human body CO2 diffuses from the body cells into the blood Deoxygenated blood returns to the heart Deoxygenated blood is carried to the lungs Oxygenated blood is returned to the heart Oxygenated blood is carried to all cells in the body Oxygen (O2 ) diffuses from the blood to the body cells Lung Heart The circulation of blood in the human body is of two types: i. Systemic circulation ii. Pulmonary circulation Line figure showing process of blood circulation Pulmonary artery Pulmonary veins Aorta, arteries and arterioles (Oxygenated blood) (Oxygenated blood) Through capillary network Veins (Deoxygenated blood) Vena cavae (Oxygenation of blood) Organs and tissues of body Heart Right atrium atrium Left Lungs (Deoxygenated blood)

140 Oasis School Science and Technology - 10 (i) Systemic Circulation The circulation of blood from the left ventricle to the right auricle of the heart via body tissues (except lungs) is called systemic circulation. In this circulation, the left ventricle contracts and pumps the oxygenated blood into aorta. The aorta gives off branches (arteries) and sub-branches (arterioles) to all the organs of the body except the lungs. From these arterioles, oxygen is diffused into the tissues. Finally, deoxygenated blood from the tissues is brought to the right auricle by the superior and inferior vena cavae. The schematic figure of systemic circulation is given below: (ii) Pulmonary Circulation The circulation of blood from the right ventricle of the heart to the left auricle via lungs is called pulmonary circulation. In this process, the right ventricle pumps deoxygenated blood to the lungs through the pulmonary artery for purification. The oxygenated blood from the lungs is brought to the left atrium of the heart by four pulmonary veins. The schematic figure of pulmonary circulation is given below: Blood Pressure Blood pressure is the force with which blood pushes against the walls of the arteries. It is generally measured in terms of how high it can push the mercury column. The normal blood pressure of a healthy young person is 120/80 mmHg. A sphygmomanometer is used to measure the blood pressure. The blood pressure is of two types: systolic blood pressure, or systole, and diastolic blood pressure, or diastole. Fact File In systemic circulation, blood does not pass through lungs. Aorta Venules Capillaries Veins Vena cavae Right auricle Left ventricle Arteries Arterioles Capillaries Tissues and cells Left auricle Right ventricle Pulmonary artery Pulmonary veins Lungs Fig. Sphygmomanometer

Oasis School Science and Technology - 10 141 (i) Systolic blood pressure When the ventricles contract, the pressure of the blood inside the arteries is the highest. This pressure of the blood is termed as systolic blood pressure, or systole. It is also called the upper limit of the arterial pressure. The systolic blood pressure of a healthy young person is about 120 millimeters of mercury (120 mm Hg). It may range from 90 mm of Hg to 130 mm of Hg in adults. (ii) Diastolic blood pressure When the ventricles relax, the pressure of the blood inside the arteries is comparatively less, which is called diastolic blood pressure. It is also called the lower limit of arterial pressure. The diastolic pressure of a healthy young person is about 80 millimeters of mercury (80 mm Hg). It may range from 60 mm of Hg to 90 mm of Hg. Causes of high blood pressure The main causes of high blood pressure are as follows: i. Smoking ii. Obesity iii. Lack of physical exercise iv. Drinking alcohol regularly v. Age more than 40 years vi. Genetic causes vii. Hypertension viii. Consumption of more salt in foods ix. Over weight Symptoms of High Blood Pressure The normal blood pressure is about 120/80 mmHg for majority of people. The blood pressure reading greater than or equal to 140/90 is called hypertension. Often people experience following symptoms due to high blood pressure. i. Headache ii. Shortness of breath iii. Nose bleeding iv. Heart tremors v. Nervousness and sweating vi. Facial reddening vii. Difficulty in sleeping viii. Anxiety ix. Nausea x. Dizziness or blurred vision It is found that, most people feel no symptoms at all. So, one has to regularly monitor his/her blood pressure even if they feel completely normal. If possible, home blood pressure monitor should be bought and regular monitoring should be done at home. If not measured and not controlled in time, high blood pressure can cause heart attack, brain haemorrhage, kidney damage, etc. without any warning symptoms. Preventive measures of high blood pressure 1. We should avoid the consumption of cold drinks. 2. Smoking and drinking should be avoided. 3. We should conduct physical exercise regularly. 4. We should consume a balanced diet. 5. We should avoid the consumption of fatty, oily and spicy foods. 6. We should avoid the consumption of fatty red meat.

142 Oasis School Science and Technology - 10 Heart Beat The continuous rhythmic beat throughout life which is produced due to contraction and relaxation of the heart muscles is called heart beat. One complete contraction and relaxation of the heart muscles makes up one heart beat. The heart of a healthy young person beats 60 – 100 times per minute. It is called heart rate. The heart beats vary according to the age, sex and condition of the body. The rate of heart beat increases with tension, physical exercise, emotion, fear and fever. Arterial Pulse Arterial pulse is the systemic contraction of the heart that can be felt as a jerk in certain arteries which are superficial in position. Each ventricular systole starts a new pulse. Arterial pulse proceeds as a wave of expansion throughout the arteries and disappears in the capillaries. Pulse rate is the same as the heart beat rate, i.e., 72 times per minute. Pulse can be felt easily in the radial artery at the wrist, temporal artery in front of the ear, common carotid artery in the neck and facial artery in the corners of the mouth. Diabetes Diabetes is a disease which is caused due to increase in the sugar level in blood. It occurs due to lack of insulin hormone. Diabetes is commonly known as sugar disease. Insulin hormone is secreted by the pancreas. Insulin regulates the amount of sugar in blood by converting extra glucose into glycogen. If there is lack of insulin hormone, the amount of glucose(sugar) increases in the blood. This condition is called diabetes. It is also called hyperglycemia. Symptoms of diabetes i. Frequent urination ii. Passing out of sugar in urine iii. Excessive thirst and hunger iv. Delay in wound healing v. Tiredness vi. Blurred vision vii. Muscle cramping Preventive measure of diabetes i. Obesity should be reduced. ii. Balanced diet should be taken. iii. Hypertension should be reduced. iv. Physical exercise should be done regularly. v. We should walk in the morning. vi. We should avoid smoking and drinking alcohol. vii. We should consume sufficient amounts of fruits and vegetables. Uric Acid Uric acid is a compound of carbon, nitrogen, oxygen and hydrogen with the formula C5 H4 N4 O3 . It forms ions and salts known as urates and acid urates, suchs as ammonium acid urate. Uric acid is a product of the metabolic breakdown of purine at liver and intestinal mucosa. It is a normal component of urine. High blood concentrations of uric

Oasis School Science and Technology - 10 143 acid can lead to gout, diabetes, kidney stones, etc. (a) Gout or arthritis (b) Obese person Hyperuricemia can lead to gout (a type of arthritis), cardiovascular disease, obesity, hypertension, etc. The skin becomes red. It causes swelling of the skin and joints of the legs with burning sensation. The person cannot walk properly. The amount of uric acid increases in the blood when the kidney cannot work effectively. In this condition, the use and exrection of uric acid does not occur properly. Uric acid removes toxins and protects the inner part of blood vessels. Uric acid is filtered by the kidneys. More metabolism of purine produces more uric acid in our body. Causes of uric acid (Gout) 1. Uric acid is caused due to kidneys fail to excrete it through urine. 2. It can be caused due to different kidney disease, kidney failure, etc. 3. It can be caused due to high metabolic rate of purines in the body. Symptoms and effects of uric acid (Gout) 1. Increased concentration of uric acid in the body 2. Joint and muscle pain due to the deposition of urate crystals 3. Pain in joints early in the morning. A painful big toe joint (i.e. gout of the big toe) is called podagra. 4. Difficulty in walking and movement 5. Swelling, burning and tenderness in joints 6. Reddish or purple skin Preventive and control measures of uric acid (gout) 1. We should reduce weight through physical exercise. 2. We should drink adequate water at regular intervals. 3. We should eat foods like cherries which contains antioxidant called anthocyanin. 4. We should avoid drinking alcohol. Fact File In human blood plasma, the reference range of uric acid is typically 3.4-7.2 mg/ dL (200-430 umol/L) for men, and 2.6- 6.1 mg/dL(140-360 umol/L) for women. Uric acid concentrations in blood plasma above and below the normal range are called hyperuricemia and hypouricemia respectively. Swollen and inflamed joint Uric acid crystals Podagra

144 Oasis School Science and Technology - 10 5. We should eat baking soda or its products. 6. We should avoid red meat (mutton, pork, etc.), legumes and sea-food. 7. We should eat low purine diet. Reasonable Fact Eating a lot of cherries is beneficial for health. Cherries contain an antioxidant called anthocyanin. It removes the harmful free substances from the body and prevents uric acid deposition in blood. Aging people should consume less salt, carbohydrates and proteins. Aging people should consume less salt, carbohydrates and proteins to prevent, or control the diseases like high blood pressure, diabetes and uric acid. Heart Attack Heart is an organ that pumps blood. It is made of cardiac muscles. It requires a constant flow of blood that is rich in oxygen. The heart's cardiac tissues receive clean blood from the coronary artery. Occasionally, fatty substances and bad cholesterol form plaque which prevent the heart from receiving oxygen-rich blood. As a result, the cardiac tissue starts to die. The blockage of the flow of pure blood into the cardiac tissues of the heart is called a heart attack.The heart suffers more harm if the blood flow is blocked for a longer period of time. A myocardial infarction is another name for a heart attack. It is a life-threatening condition. To increase the chance of survival, it needs to be treated within two hours. If a heart attack causes significant damage to the heart, the victim will die when the heart stops beating. It is called cardiac arrest. We should be able to determine whether it is a heart attack or not before it is too late. After that, we can use the treatments to prolong life. A healthy lifestyle helps to reduce the chances of a heart attack. Heart attacks are most frequently caused by diabetes, kidney disease, deep vein thrombosis, and high blood pressure. So it is suggested to pass a healthy and active life to avoid heart attack. Fig: heart attack

Oasis School Science and Technology - 10 145 Reasonable Fact We should avoid sedentary life. We should avoid sedentary life to prevent diabetes, obesity and heart attack. Symptoms of heart attack 1. Unusual fatigue. 2. Chest pain, discomfort in jaw, neck or back. 3. Discomfort in one or both shoulders. 4. Short of breath followed by chest pain. 5. Feeling dizzy or fainting. Causes of heart attack 1. Coronary heart disease can be caused by smoking and drinking alcohol. CHD can cause a heart attack. 2. Diabetes, high cholesterol, and high blood pressure can all damage the coronary artery and lead to a heart attack. 3. Heart attacks can be caused by obesity. 4. An oxygen deficiency in the blood can trigger a heart attack. Carbon monoxide poisoning depletes the blood of oxygen, it can result in a heart attack. 5. Use of drugs can constrict the coronary arteries. As a result, blood cannot flow properly into the heart and the heart tissues start to die. 6. Male aged older than 45 and female aged older than 55 have higher risk of heart attack. It could be hereditary. Preventive measures: As we discussed above heart attack is fatal. It is caused by our lifestyle. We must improve our lifestyle to prevent heart attacks. Some common ways to prevent heart attack are listed below: 1. Eat healthy diet. 2. Be physically active. 3. Maintain a healthy weight. 4. Avoid smoking and reduce alcohol consumption. 5. Manage high blood pressure and diabetes. 6. Keep cholesterol under control. Reasonable Fact Smoking can cause a heart attack. Smoking can lead to a heart attack because nicotine raises blood pressure, which is one of the risk factors for a heart attack. Fact File It is advised to engage in low-impact activities like walking, swimming, and cycling to lower your risk of having a heart attack.

146 Oasis School Science and Technology - 10 Diagnosis and curative measures of heart attack Checking blood pressure, blood tests, electrocardiogram, chest x-ray, echocardiogram, angiogram, and Cardiac CT , Coronary Angiogram and MRI can all be used to diagnose a heart attack. Doctors will begin treatment if we have symptoms of a heart attack. During an emergency, call for help, stop driving, take an aspirin, remain calm, and lie down. Coughing, putting pressure on the heart, and panicking will worsen the situation. Curative health services are provided to patients in hospitals as soon as a heart attack is confirmed. The primary goal of curative health care is to restore blood supply to the heart. Angiography and bypass surgery are the two main methods for restoring blood flow. Angiography A heart attack can be effectively treated with angiography. It locates the blood clot using an x-ray imaging technique. Angiography can take anywhere from 30 minutes to an hour. A mild sedative is given to the patients. Doctors clean the area in the arm and make a small hole. A catheter is inserted through an artery. A catheter is a hollow, thin tube. It is then transferred to the heart. X-ray images help doctors in determining the location of the catheter. A special dye is injected through the catheter, and multiple x-ray images are continuously taken to monitor the flow of contrast medium (dye) through the artery. The dye will draw attention to any blood clots or other disruptions in blood flow. Doctors observe angiogram. Angiogram is an image formed during angiography. When a blood clot is found, doctors will insert a metallic mesh tube (stent) into the narrowed or blocked artery. It helps the blood supply to the heart tissues. First of all, they push a tiny balloon through the blockage that removes the blood clot. Then they put stent so that the artery won't close again. Balloon is removed later. This process is called Percutaneous coronary intervention (PCI). Angiography is an effective way to treat a heart attack. It uses an x-ray imaging technique to find the blood clot. After that a mesh tube and a tiny balloon is used to open the blockage. Angiography is a relatively safe procedure. It does not hurt but we can feel the catheter being moved in the artery. In case devices for angiogram and angioplasty are not available aspirin or other chemicals are used to make blood thinner and save life until proper treatment is available. Fig: a patient who is being treated by angiography Fact File Angiography is classified into several types based on the organ being examined. Angiography is used to examine kidneys, lungs, and other organs.

Oasis School Science and Technology - 10 147 Reasonable Fact A thin metallic mesh tube is inserted through the blockage during angiography. A thin metallic mesh tube is inserted through the blockage during angiography because it helps to pass blood through the blockage into the heart. Bypass Surgery The narrowing of the coronary artery is called coronary artery disease. The blood cannot reach heart tissues through narrow arteries. If many coronary arteries are blocked and oxygen is not supplied enough into the heart the doctors will suggest bypass surgery. Thus, bypass surgery means finding alternative arteries to supply blood to the cardiac tissue of the heart when the majority of blood vessels are blocked or are very narrow. The objective of bypass surgery is to find a healthy artery that supplies blood to hand or chest. We can also use saphenous vein from thigh. Then it is used to supply fresh blood to the heart. Its one end is connected to the aorta that supplies pure blood and another end is connected to the coronary artery beyond the blockage. One or many bypasses are made at a time based on the number of narrow coronary arteries. In bypass surgery, the sternum bone is cut in half along its length. They push each piece sideways to see the heart. Then the doctors will connect a heartlung bypass machine to the heart to pump blood. The heart itself is stopped for a certain duration during the surgery. The bypass surgery is only done when there is an emergency and nothing else can be done. It can sometimes lead to pneumonia, failure of the kidneys, loss of blood, and even death. Reasonable Fact Many bypasses are made during single surgery if many coronary arteries are narrow. If many coronary arteries are narrow, there will be a shortage of oxygen in the heart that can cause heart attack again. So, doctors make many bypasses to supply more pure blood into the heart. Fact File Coronary artery bypass grafting (CABG) is used to treat heart attacks. Many coronary arteries can be bypassed in a single surgery. Fig: Coronary bypass surgery

148 Oasis School Science and Technology - 10 Cardiac Rehabilitation Cardiac rehab is a health service that helps people get better. It includes exercise, support, counseling etc. to get heart patient get better. It can last for 2 to 8 months. Reasonable Thinking Skill Reasonable Thinking Skill R T S 1. Study the given diagram of the human heart and answer the following question. i. Why is chamber B and D bigger than chamber A and C? B and D are bigger than chambers A and C because B and D are ventricles, they must be bigger and thicker so that they can push blood into the artery. ii. Why is the wall of chamber D thicker than that of chamber B? Chamber D is the left ventricle. It has to push blood all over the body whereas chamber B is the right ventricle. It has to push blood up to the lungs only which is closer to the heart. So, chamber D, the left ventricle, is thicker than chamber B (right ventricle) to produce more force to push blood with more pressure. iii. Why is A and B of the picture-coloured blue whereas the C and D of the picture is coloured red? A and B of the picture of the heart are blue to represent the presence of impure blood (deoxygenated blood). C and D of the picture of the heart are red to represent the presence of pure blood (oxygenated blood). iv. What are the upper chambers A and C called? The upper chambers are called auricles. A is the right auricle and C is the left auricle. v. Which tissue makes this organ? Which artery supplies pure blood for this organ? Cardiac tissue makes this organ. The coronary artery supplies pure blood to this organ. 2. Whenever a person eats red meat, fried grams, peanuts and cold beer, his joint hurts and swells. What is the disease he is suffering from? What kind of life style should he live to avoid uric acid or gout? What kind of consequences will he suffer otherwise? If the person suffers from joint pain and swelling if he consumes red meat, peanut or alcohol, the most probable diseases is high uric acid and gout. The person should live the following life style: i. Consume high-fibre food. Especially vegetables, fruits and grains. ii. Reduce purine-rich food such as red meat, organ meat, fish, poultry and legumes. iii. Reduce consumption of junk food, processed food and sugary fruits. iv. Drink more water. Reduce sugary drinks and beverages. v. Avoid alcohol. vi. Manage blood sugar and body mass index. vii. Eat cherries and vitamin C. viii. Regular exercise is recommended. The above activities will definitely help to avoid high uric acid. Otherwise, the person will suffer from the following consequences: A B D C

Oasis School Science and Technology - 10 149 i. Person will suffer from permanent bone, tissue and joint damage. ii. It can damage kidneys. iii. It can cause heart disease. iv. Long-term gout can cause eye cataracts and dry eyes. 3. A person has pain in the chest that is slowly rising to the jaws. What could be the most probable cause? If a person has chest pain that is slowly rising to the jaws, the most probable cause is a heart attack. 4. What is the cause of systolic pressure in arteries when the left ventricle contracts? The cause of systolic pressure in arteries when the left ventricle contracts is the flow of pressurised blood into the arteries due to contraction. The fast-flowing pressurised blood pushes the wall of arteries and produces greater pressure. 5. If a person has chest pain and is brought to the hospital, what kind of test should be prioritized? If a person has chest pain and is brought to the hospital, then the tests that can detect heart attack and coronary blockage, should be prioritized. 6. Haemophilic person loses a lot of blood even from a minor injury. Haemophilic person lose a lot of blood even from minor injuries because they have a mutation in one of the genes due to which fibrinogen cannot work properly to clot blood. 7. Circulatory system, respiratory system and digestive system are interrelated. Clarify. The respiratory system is responsible for absorbing oxygen from the lungs and giving it to the cells. The digestive system is responsible for converting food into nutrients. The circulatory system is responsible for absorbing nutrients from the intestine and gives to the cell. Only then the mitochondria of the cell, use oxygen and nutrients to produce energy through respiration. Hence respiratory system, digestive system and circulatory system work together to produce energy for our body and remove waste. 8. If a person is suffering from excessive thirst, excessive hunger, frequent urination,unconsciousness and blurry vision. What disease is he suffering from? What are its preventive measures? If a person is suffering from excessive thirst, excessive hunger, frequent urination, unconsciousness and blurry vision, then the person is suffering from diabetes. The measures to save the life from this disease are: i. We should do regular physical exercise, reduce obesity and eat freshly prepared foods. ii. We should consume low-carb food. iii. We should decrease the consumption of processed foods, quit smoking and quit alcohol. iv. We should consume a few cups of sugarless tea and coffee because they are rich in antioxidants. 9. Study the table and answer the following questions: Person Wounds Blood leakage A Deep cut Faster blood leakage rate, stopped only after first aid B Minor cut Slower blood leakage rate, stopped naturally C Minor cut Slower blood leakage rate, did not stopped after first aid i. Why did not blood clot in person C?

150 Oasis School Science and Technology - 10 The blood did not clot in person C, because he is suffering from haemophilia. ii. Why did blood leak faster in person A? Was it a ruptured artery or vein? The blood leaked faster in person A because it was a deep cut in arteries. The blood flows with high pressure in the artery so it is difficult to prevent blood loss with minor first aid. iii. Which person’s life is at threat among A and B? Why? Among persons A and B, the life of person A is at threat. It is because person A has a deep cut in an artery. The blood flows faster with high pressure. Lots of blood could be lost and a person can faint or die. 10. Can cell and tissues survive if there is no circulatory system? The cells and tissues cannot survive if there is no circulatory system because it is responsible for absorbing nutrients from the intestine and oxygen from lungs then transporting it to the cell. It also helps to remove toxic substances from cells and tissues. Exercises 1. Choose the best answer from the given alternatives. a. Why is RBC called a prokaryotic cell? i. because it is small ii. because it is old iii. because it is red iv. because it has no nucleus b. What is the lack of red blood cells in the body for a longer duration called? i. leukaemia ii. leukopenia iii. anaemia iv. iron deficiency c. Blood is connective tissue. Why? i. it attaches skin to flesh ii. it joins bone to the flesh iii. it reaches every cell in the body iv. it connects the heart and lungs d. Which blood vessel despite being an artery has impure blood? i. aorta ii. pulmonary vein iii. pulmonary artery iv. coronary artery e. What converts extra glucose in the blood to glycogen? i. insulin ii. glucagon iii. amylase iv. pepsin f. What is the first aid for heart attack when patient is unconscious? i. CPR ii. aspirin iii. heart bypass surgery iv. electric shock 2. Define the following terms with required examples. a. Blood b. Plasma c. Red blood cells d. White blood cells e. Blood platelets f. Anaemia g. Leukaemia h. Leukopenia i. Auricles j. Ventricles k. Blood vessels l. Arteries m. Veins n. Capillaries o. Systemic circulation