Chapter 6. REACHING THE AGE OF ADOLESCENCE

Exercises :

1. What is the term used for chemical secretions of endocrine glands responsible for changes taking place in the body?

Answer : The term used for chemical secretions of endocrine glands responsible for changes in the body is "hormones."

2. Define adolescence.

Answer : Growing up is a natural process. The period of life, when the body undergoes changes, leading to reproductive maturity, is called adolescence. Adolescence begins around the age of 11 and lasts upto 18 or 19 years of age.

3. What is menstruation? Explain.

Answer : Menstruation is a natural process that happens to girls and women. It is when blood and tissue from the uterus come out of the body through the vagina. It usually happens every month and is a sign that a girl or woman's body is preparing for pregnancy. If pregnancy doesn't occur, the lining of the uterus is shed, and the cycle begins again.

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

Answer : During puberty, several significant changes occur in the body. These changes are :

(i) increase in height 

(ii) Change in body shape

(iii) Voice change

(iv) Development of sexual organs

(v) Reaching mental, intellectual and emotional maturity

(vi) Increased activity of sweat and sebaceous glands

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

Answer :

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

Answer : Sex hormones are special chemicals in our bodies that are responsible for the changes that happen during puberty. They are called sex hormones because they control the development of our sexual characteristics, such as the growth of breasts and the deepening of the voice.

They are named sex hormones because they are involved in determining and regulating our sexual characteristics, such as the development of breasts, facial hair, body shape, and voice changes.

The function of sex hormones differs between males and females are :

In males, testosterone is responsible for the development of masculine features during puberty, including the growth of facial and body hair, deepening of the voice, and the development of muscles and reproductive organs.

In females, estrogen and progesterone play crucial roles in the development of feminine features. Estrogen is involved in the growth of breasts, regulation of the menstrual cycle, and the development of female reproductive organs. Progesterone is important for preparing the uterus for pregnancy and maintaining a healthy pregnancy.

7. Choose the correct option.
(a) Adolescents should be careful about what they eat, because
(i) proper diet develops their brains.
(ii) proper diet is needed for the rapid growth taking place in their body.
(iii) adolescents feel hungry all the time.
(iv) taste buds are well developed in teenagers.

Answer : (ii) proper diet is needed for the rapid growth taking place in their body.

(b) Reproductive age in women starts when their
(i) menstruation starts.
(ii) breasts start developing.
(iii) body weight increases.
(iv) height increases.

Answer : (i) menstruation starts.

(c) The right meal for adolescents consists of
(i) chips, noodles, coke.
(ii) chapati, dal, vegetables.
(iii) rice, noodles and burger.
(iv) vegetable cutlets, chips and lemon drink.

Answer : (ii) chapati, dal, vegetables.

8. Write notes on—
(a) Adam’s apple.
(b) Secondary sexual characters.
(c) Sex determination in the unborn baby.

Answer : (a) Adam’s apple : At puberty, the voice box or the larynx begins to grow. Boys develop larger voice  boxes. The growing voice box in boys can be seen as a protruding part of the throat called Adam’s apple . In girls, the larynx is hardly visible from the outside because of its small size. Generally, girls have a high pitched voice, whereas boys have a deep voice .                                                           
(b) Secondary sexual characters: Secondary sexual characteristics are physical changes that occur during puberty that differentiate males and females. They are different from primary sexual characteristics, which are the reproductive organs themselves.

Some examples of secondary sexual characteristics are:

(i) In males, the growth of facial hair, deepening of the voice, and increased muscle mass.

(ii) In females, the development of breasts, widening of hips, and the onset of menstruation.

(c) 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 the sex chromosomes, named X and Y. A female has two X chromosomes, while a male has one X and one Y chromosome. The gametes (egg and sperm) have only one set of chromosomes. The unfertilised egg always has one X chromosome. But sperms are of two kinds. One kind has an X chromosome, and the other kind has a Y chromosome. When a sperm containing X chromosome fertilises the egg, the zygote 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

Answer :

10. The table below shows the data on likely heights of boys and girls as they grow in age. Draw graphs showing height and age for both boys and girls on the same graph paper. What conclusions can be drawn from these graphs?