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., , Science 8th Std, 13. Reaching the Age of Adolescence, , Ll. What is the term used for secretions of endocrine glands responsible, for changes taking place in the body?, Hormones are the term used for secretions of endocrine glands, responsible for changes taking place in the body., , . Define adolescence., Adolescence. The period of life, when the body undergoes changes,, leading to reproductive maturity is called adolescence., , 3. What is menstruation? Explain., , If fertilization does not take place then the thickened inner wall of the, , uterus break down along with the blood vessels and move out of the, , vagina in the form of bleeding. This is known as menstruation which, lasts for 4-7 days., 4. List the changes in the body that take place at puberty., , The changes in the body that take place at puberty are:, , * Increase in height., , * Change in body shape — Boys have broader shoulders and wider, chests. In girls, the region below the waist becomes wider., , * There is a change in voice. Girls have a high-pitched voice, whereas, boys have a deep voice., , * The secretion of sweat glands and sebaceous glands (oil glands), increases., , * There is the development of sex organs. Male sex organs (testes,, penis) are fully developed and produce sperms. In girls, the ovaries, enlarge and eggs begin to mature. Ovaries start releasing matured, , eggs. ‘, , * A person reaches mental, intellectual, and emotional maturity., , ~, , ES, , . Prepare a table having two columns depicting names of endocrine, , glands and hormones secreted by them., , Endocrine organs Hormones secreted, 1. Pituitary gland (i) Growth hormone, (ii) ACTH, (iii) FSH, (iv) TSH, (v) Oxytocin, 2. Thyroid Thyroxine, 3. Adrenal Adrenaline, 4, Pancreas (i) Insulin, (ii) Glucagon, 5. Ovary ( Estrogen, _ (ii) Progesterone, 6. Testis Testosterone, , . What are sex hormones? Why are they named so? State their function., , Sex hormones are hormones secreted by the testes and ovaries. They, are named so because they are responsible for the male and female, secondary sexual characters. The function of male sex hormones is to, cause changes in boys like the growth of facial hair, that is mustaches, and beard, The function of the female sex hormone is to cause changes, in girls like the development of breasts., , Choose the correct option., , (a) Adolescents should be careful about what they cat, because:, (ii) Proper diet is needed for the rapid growth taking place in their body., (b) Reproductive age in a woman starts when their:(i) Menstruation starts.
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(c) The right meal for adolescents consists of:, , (ii) Chapati. dal, vegetables., , 8. Write notes on:, , (i) Adam’s apple, , (ii) Secondary sexual characters., , (iii) Sex determination in the unborn baby., , (i) Adam’s apple: Adam’s apple is a protruding part of the throat in, adolescent boys. This is a lange voice box or the larynx. Due to this,, the voice in boys is deep. If the muscles of the growing voice box go, out of control then the voice becomes hoarse., , (ii) Secondary sexual characters: The features which help to distinguish, the male from the female are called secondary sexual characters., , The secondary sexual characters in girls are:, , * The hips become wider., , * Breasts begin to develop., , * Hair grows under the arms and in the region above the thighs., * Formation of eggs in the ovaries., , ‘The secondary sexual characters in boys are:, , * Hair develops on the chest., , * Facial hair, that is mustaches and beard begins to grow., , * Hair grows under the arms and in the public region., , * Formation of sperms in the testes., , (iii) Sex determination in the unborn baby: All human beings have 23, pairs of chromosomes in the nuclei of their cells. Two chromosomes, out of these are sex chromosomes. A female has two X chromosomes, whereas a male has one X and one Y chromosome. The unfertilized, egg always has one X chromosome. But testes produce two kinds, , of sperms. One kind has an X chromosome and the other kind has a, Y chromosome., , rm containing X chromosome fertilizes the eg cS, two X chromosomes and develops into a femae, ntaining Y chromosomes fertilizes the egg, the °, chromosome and develops, , When a spe, zygote produced has, , baby. If the sperm co, zygote produced has one X and one Y, , into a male baby., 9. Word game: Use the clues the work out the words., Across, 3. Protruding voice box in boys, 4. Glands without ducts, 7. Endocrine gland attached to the brain, 8. Secretion of endocrine glands, 9. Pancreatic hormone, 10. Female hormone, , , , , , , , , , Down &], 1, Male hormone {al, 2. Secrets thyroxine te], 3. Another term for teenage ra to}, , ADACHQCOE, , , , , , fee, , , , sJeToleTayi Intel, , , , , , , , , , , , , , , , , , , , , , , , , , , , :, gq fy, fal __[e] Pelt Toy +, To ;, foTaeTolsye) * [sya af), Y cy ral :, REEEETES| &GEE PREM x : c, [I, x ‘, x ,, =
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Py... als shows the data on the likely heights of b i, grow in age. Draw graphs showing hei ; Sinieiaen —, girls on the same graph paper. What c, , , , , , , , , , , , , , , , , , , , , , , , these graphs? onclusions can be drawn from, Age | Height (cm), (Years) Boys Girls, 0 53 53, 96 92, 8 114 | 110, 12 129 | 133 Sone, 16 150 | 150, 20 173 | 165, , , , , , , , , , , , , , The conclusion drawn from these graphs is that at the time of birth the, height of boys and girls is the same. At the age of 4-8 boys are taller, than girls and at the age between 8-12 girls become taller than boys., But by the time they reach the age of 16 the height of both boys and, girls is the same. After this, the boys attain more height than girls., 11. What are target sites?, Endocrine glands release hormones into the bloodstream to reach a, particular body part called the target site., 12. What are chromosomes’?, Chromosomes are the thread-like structures present in fertilized eggs, , containing instructions for determining the sex of the unborn baby, and other traits.
