Lesson: Reaching the Age of Adolescence Science
Exercise:

Question: 1

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

Solution:

Endocrine gland secrets various chemicals which are directly mixed into the blood stream that cause changes in body parts. These chemicals are known as hormones and are responsible for the changes in the body during adolescence.

Question: 2

Define adolescence.

Solution:

According to WHO, adolescence is the period in human growth and development that occurs after childhood and before adulthood, between years 10 to19. It represents one of the critical transitions in the life span and is characterized by a tremendous pace in growth and change that is second only to that of infancy.

Question: 3

What is menstruation? Explain.

Solution:

When a human egg remains unfertilized and pregnancy does not occur, then mucosal tissue and blood is discharged from the inner lining of the uterus, and this process is known as menstruation, which occurs once in a month.

Question: 4

List changes in the body that take place at puberty.

Solution:

Girls and boys develop many changes in their physical appearances during puberty. The changes are listed below.

GIRLS:

·         Sudden increase in weight and height

·         Waist becomes wider

·         Fat accumulation in and around the waist region

·         Growth of hair in underarms, hands, legs and pubic area

·         Appearance of acne due to excessive oil secretion

·         Ovary enlarges and starts releasing eggs and menstruation starts

BOYS:

·         Shoulders broaden and chest becomes wider

·         Develops hair on face, hands, legs, underarms and pubic area

·         Appearance of acne due to excessive oil secretion

·         Penis becomes larger andtesticles grow and produce sperms.

·         Develop protruding larynx and hoarse voice

Question: 5

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

Solution:

Endocrine gland

Hormones

Adrenal

Adrenalin

Ovary

Oestrogen

Pituitary

Growth hormones

Pancreas

Insulin

Thyroid

Thyroxin

Testes

Testosterone

Question: 6

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

Solution:

Sex hormones are responsible for secondary sexual characters in both males and females. They also regulate and help in proper functioning of the sex organs. The secretion of sex hormones is controlled by the pituitary gland.

Functions of sex hormones:
Testosterone: This hormone is produced by the testes and brings about secondary sex characters in boys at puberty, such as, the growth of hair on the face and all over the body, getting taller, development of the reproductive organs, deepening of the voice, etc.
Oestrogen: This hormone is produced by ovaries and is responsible for the development of secondary sexual characters in females at puberty, such as, the breast growth, development of female reproductive organs, etc.

Question: 7

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

 (ii) Reproductive age in women starts when their
(a) menstruation starts.
(b) breasts start developing.
(c) body weight increases.
(d) height increases.

 (iii) The right meal for adolescents consists of
(a) chips, noodles, coke.
(b) chapatti, dal, vegetables.
(c) rice, noodles and French fries.
(d) cutlets, chips and lemon drink.

Solution:

(i)        (b)

(ii)     (a)

(iii)    (b)

Question: 8

Write a short note on:

(a) Adam’s apple.

(b) Secondary sexual characters.

(c) Sex determination in unborn baby.

Solution:

(a) Adam's apple: The protruding part of the throat is called the Adam’s apple. It is an enlarged larynx visible from outside in boys, at the onset of puberty.

(b) Secondary sexual characters: Secondary sexual characters help to differentiate male and female genders from their physical appearances. These are developed at the time of puberty.

GIRLS:

·         Sudden increase in weight and height

·         Waist becomes wider.

·         Accumulation of fat in and around the waist

·         Growth of hair on underarms, hands, legs and pubic area

·         Appearance of acne due to excessive oil secretion

·         Ovary enlarges and starts releasing eggs.

BOYS:

·         Shoulders broaden and chest becomes wider.

·         Develops hair on the face, hands, legs, underarms and pubic area

·         Appearance of acne due to excessive oil secretion

·         Penis becomes larger. Testicles grow and produce sperms.

·         Develop protruding larynx and hoarse voice.

 (c) Sex determination of a baby before birth: 

Sex of a child is determined by chromosomes. Every human has 23 pairs of chromosomes, of which, one pair is different in male and female respectively. Female has XX chromosome pair whereas male has XY chromosome pair.

Egg released by an ovary always has X chromosome. If the egg is fertilized by a sperm containing X chromosome, then the sex of the child will be female. If the egg is fertilized by a sperm containing Y chromosome, then the sex of the child will be male.

Question: 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 thyroxin
3. Another term for teenage
5. Hormone reaches here through blood stream
6. Voice box
7. Term for changes at adolescence

Solution:

Question: 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?

Age (Years)

Height (cm)

Boys Girls

0

53

53

4

96

92

8

114

110

12

129

133

16

150

150

20

173

165

Solution:

The graph establishes a relation between the age and height of both boys and girls. With reference to the above graph, it is observed that during the age of 4-8 years, girls have lesser height as compared to boys. However, when girls reach 12- 13 years, their height shows a sudden increase than boys. In the subsequent years, growth in both sexes becomes stable.