GSEB Solutions Class 8 Science Chapter 10 Reaching the Age of Adolescence

Gujarat Board GSEB Textbook Solutions Class 8 Science Chapter 10 Reaching the Age of Adolescence Textbook Questions and Answers, Notes Pdf.

Gujarat Board Textbook Solutions Class 8 Science Chapter 10 Reaching the Age of Adolescence

Gujarat Board Class 8 Science Reaching the Age of Adolescence Textbook Questions and Answers

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

Question 2.
Define adolescence.
Answer:
The period of life, when the body under¬goes changes, leading to reproductive maturity is called adolescence.

Question 3.
What is menstruation? Explain.
Answer:
When the egg produced by the ovary does not get fertilized, the released egg and the thickened lining of the uterus along with its blood vessels are shed off. This causes bleeding in women which is called menstruation. Menstruation occurs once in about 28 to 30 days.

Question 4.
List the changes in the body that take place at puberty.
Answer:
The changes in the body at puberty are:

1. A sudden increase in height.
2. The bones of arms and legs elongate and make a person tall.
3. Growing hair at different parts of the body.
4. The voice of a boy gets hoarded.
5. Development of sex organs.
6.  Growth of mustaches and beards in the boys.
7. The breast in girls develops and hips become wider whereas in boys shoulders generally broaden.

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

1. Pituitary gland
2. Ovaries
3. Testes
4. Thyroid
5. Pancreas
6. Adrenal glands

Hormones:

1. Growth hormones
2. Estrogen
3. Testosterone
4. Thyroxine
5. Insulin
6. Adrenalin

Question 6.
What are sex hormones? Why are they named so? State their functions.
Answer:
The hormones which help and control the formation of secondary sexual characters are called sex hormones. They are called sex hormones because they control the sexual activities and help us to distinguish boys from girls. The sex hormones help to develop secondary sexual characters. Such as, in boys, they control the formation of sperms by testes and growth of facial hair. In girls, they help to develop breasts, milk-secreting glands, or mammary glands.

Question 7.
Choose the correct option.
(a) Adolescents should be careful about what they eat, because
(i) proper diet develops their brains.
(ii) A 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.

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

(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:
(a) (ii) A proper diet is needed for the rapid growth taking place in their body.
(b) (i) menstruation starts.
(c) (ii) chapati, dal, vegetables.

Question 8.
Write notes on:
(a) Adam’s apple
(b) Secondary sexual characters
(c) Sex determination in the unborn babies.
Answer:
(a) Adam’s apple: The protruding part of the throat in boys is called Adam’s apple. It is the enlarged voice box or larynx. It makes the voice of boys coarse.
(b) Secondary sexual characters: The characters which help to distinguish the male from female are called secondary sexual characters. The characters like the hair on chest and underarms, development of breast, beard, and mustaches are called secondary sexual characters.
(c) Sex determination in unborn babies: The sex of the unborn babies is determined by the sex chromosomes. An unfertilized egg always has X chromosomes. Sperms are of two types. One contains X chromosomes and the other contains Y chromosomes. If sperm contributes a Y chromosome to the egg at fertilization, the zygote would develop into a male child. If a sperm containing the X chromosome fertilizes the egg, the zygote would develop into a female child.

Question 9.
Word game: Use the clues to work out the words.

Across:
3. Protruding voice box in beys
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
2. Secretes thyroxine
3. Another term for teenage
5. Hormone reaches here through the bloodstream
6. Voicebox
7. The term for changes at adolescence.
Answer:

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?

Answer:

We conclude that initially, girls grow faster than boys but by about 18 years of age both reach about their maximum height. The rate of growth in height varies in different individuals.