Class 8 NCERT Science Chap 10 Solution

CHAPTER 10

REACHING THE AGE OF ADOLESCENCE

Chapter 10 Reaching The Age of ADOLESCENCE SCIENCE NCERT of CLASS 8 complete solution and some important points are given. This will help student to understand the topics of CHAPTER 10 REACHING THE AGE OF ADOLESCENCE of Class 8. Students can solve the textbook Questions easily and understand all the important points of chapter.

Important Points:-

a) Adam's apple:- At puberty, the voice box begin to grow in boys and develop as a large voice box this developed part seen at the throat known as Adam's apple.

b) Adolscence:- The period of life when reproductive  maturity is growing  up is called Adolscence.

c) Adernalin :- Kind of gland which release hormone  to adjust body from  when we are facing emergency situation stress.

d)  Balanced Diet:-  A diet  which contain all nutritional value like carbohydrates, fats, vitamins etc.is known as balanced diet.

e) Endocrine  gland:- The glands which release their secretion direct in blood are known as endocrine gland.

f) Hormone:- Chemical substance which helps body in development and growth.

g) Insulin:- Kind of hormones which released by pancreas help in the  maintain of sugar level in blood.

h) Pitutary  gland:- The gland which release growth hormones and also controls secretion of other glands like thyroid, Adernalin is known as Pitutary gland.

i) Puberty:- The changes which occur during th age of Adolescence is known as Puberty.

j)Sex chromosomes:- The chromosomes which are responsible for the determination of sex of the foetus are known as Sex chromosomes.

These are the important points about the Chapter 10 REACHING THE AGE OF ADOLESCENCE it helps students to understand the chapter.

The solution of textbook questions of Chapter 10 REACHING THE AGE  OF ADOLESCENCE of Class 8 is given below.

Ques 1. What is the term used for secretion of endocrine glands responsible for changes taking place in the body.

Ans.  Hormones are secretion of endocrine gland responsible for changes taking place in the body.

Ques 2. Define adolescence.

Ans. The period of life when the body undergoes

changes leading to reproductive maturity is called Adolescence.

Ques 3. What is mensuration? Explain.

Ans. The monthly discharge of blood from uterus of a non pregnant women from puberty to menopause is called  mensuration. The menstrual cycle is controlled by hormones . The  cycle include the maturation  of the egg its release, thickening of the uterine wall and its breakdown if pregnancy does not occur. Mensuration occurs once in about 28 to 30 days.

Ques 4. List changes in the body that take place at puberty.

Ans.a) Height and weight increases.

b) Muscles became stronger.

c) Change in the body shape with broader shoulders.

d)Vocal cords get thicker and longer in boys.

e) They attain mental, intellectual and emotional maturity , learning capacity increases.

f)Sweat and oil glands became more active.

g)Males develop a moustache and a beard.

h) Reproductive function begins with the release of follicle stimulating.

Ques 5. Prepare a table having  two columns depicting the names of the endocrine  glands and hormones secreted by them.

Ans. 

Endocrine glands	Hormones
1. Pituitary gland	Growth hormones,follicle stimulating hormone,leutenizing hormones, vasopressin, oxytocin, prolactin
2. Ovaries	Estrogen, Progestrone
3. Testes	Testosterone
4. Thyroid	Thyroxine, calcitonim
5. Pancreas	Insulin,Gulcagon
6. Adrenal glands	Adrenaline

Ques 6. What are sex hormones? Why are they named so? State their function.

Ans. The hormones that are responsible for the male and female secondary sexual characters are called Testosterone in males and estrogen and progesterone in females are sex hormones. Sex hormones are named so as they have an effect on the sexual features of an organism.

Function:-

Sex  steriods play important role in inducing the body changes known as primary sex  characteristic and   secondary sex characteristics.

Ques 7. Choose the correct option.

a) Adolescents should be careful about they eat, because

i) proper diet develops their brains.

ii)proper diet is needed for the rapid growing taking place in the body.

iii) Adolescents feel hungry all the time.

iv) taste buds are well developed in teenagers.

b) Reproductive age in women starts when their

i) mensuration starts.

ii) breasts start developing.

iii) body weight

iv)height increases 

c) The right meal for Adolscents consists of

i) Chips,noodles,coke

ii) chapati, dal, Vegetables

iii) rice,noodles and burger.

iv) vegetables cutlets,chips and lemon drink.

Ans. a) proper diet is needed for the rapid growth taking place in their body.

b) breasts start developing.

c) chapati,dal, vegetables.

Ques 8. Write notes on-

a) Adam's apple

b) Secondary sexual characters

c) Sex determination in the unborn baby.

Ans.a) At puberty, the voice box or the larynx begin to grow. Boys develop larger voice boxes. The growth of voice box in boys   can be seen as protruding part of the throat called the Adam's apple.

 

b) A characteristic of animals that differs  between the male and female sexes is called  secondary sexual characters. Males have change in voice, broadening of shoulders,beard are secondary sexual characters.

c) Zygote is the instruction for determining the sex of the baby. This instruction is present in the thread like structures called Chromosomes in the fertilised egg. Two chromosomes out of these are sex chromosomes  name X and Y a female has two X chromosome while a male has one X and one Y chromosomes. When a sperm containing a X chromosome fertilise ,the egg would have two X chromosomes and develop into a female Child.

If the sperm contributes a Y chromosome to the egg(ovum) at fertilisation, the zygote would develop into a male Child.

9. Word game :

Use the clues to work out the words.

Across

3. Protruding voice box in boys

4. Glands without ducts

7. Endocrine gland attached to brain

8. Secretion of endocrine glands

9. Pancreatic hormone

10. Female hormone

Down

1. Male hormone

2. Secretes thyroxine

3. Another term for teenage

5. Hormone reaches here through blood stream

6. Voice box

7. Term for changes at adolescence

Soln:

Across

1. Adam’s apple
2. Endocrine
3. Pituitary
4. Hormone
5. Insulin
6. Estrogen

Down

1. Testosterone
2. Thyroid
3. Adolescence
4. Target site
5. Larynx
6. Puberty

This the complete solution of CHAPTER 10 REACHING THE AGE OF ADOLESCENCE OF CLASS 8 SCIENCE NCERT .The solution is prepared by subject expert and the solution is given according to latest CBSE SYLLBUS.

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