Reaching the Age of Adolescence Class 8 Question Answers

“Reaching the Age of Adolescence” is Chapter 10 taken from the JKBOSE textbook of Science for students of Class 8th. In the previous post, I provided you with Questions and Answers for Chapter 9 Force and Pressure. This post is about the Reaching the Age of Adolescence Class 8 Question Answers. Before we move on to solutions you must have your basics clear. So, let me begin by giving you a brief overview of what you have studied in this chapter.

Reaching the Age of Adolescence Class 8 Question Answers

Overview of Chapter

• ADOLESCENCE AND PUBERTY.
• CHANGES AT PUBERTY.
  1. Increase in Height.
  2. Change in Body Shape.
  3. Voice Change.
  4. Increased Activity of Sweat and Sebaceous Glands.
  5. Development of Sex Organs.
  6. Reaching Mental, Intellectual and Emotional Maturity.
• SECONDARY SEXUAL CHARACTERS.
• ROLE OF HORMONES IN INITIATING REPRODUCTIVE FUNCTION.
• REPRODUCTIVE PHASE OF LIFE IN HUMANS.
• HOW IS THE SEX OF THE BABY DETERMINED?
• HORMONES OTHER THAN SEX HORMONES.
• ROLE OF HORMONES IN COMPLETING THE LIFE HISTORY OF INSECTS AND FROGS.
• REPRODUCTIVE HEALTH.
  1. Nutritional Needs of the Adolescents.
  2. Personal Hygiene.
  3. Physical exercise.
  4. Say “NO” to Drugs.

ADOLESCENCE AND PUBERTY: The period of life, when the body changes, leading to reproductive maturity, is called adolescence. Adolescence begins around the age of 11 and lasts up to 18 or 19 years of age. The period during which adolescent boys and girls reach sexual maturity and become capable of reproduction is called puberty.

CHANGES AT PUBERTY: Puberty marks the beginning of the reproductive period when one becomes capable of reproduction.

1. Increase in Height: The most prominent change during puberty is a sudden increase in height of boys and girls. Initially, girls grow faster than boys but by about 18 years of age, both boys and girls reach their maximum height.
2. Change in Body Shape: Boys have broad shoulders, more muscles than girls, Adam’s Apple, and also develop facial hair (moustache and beard). Girls have wider chests, broader hips, and breast development in girls.
3. Voice Change: The growth of the voice box in boys is much more than in girls. The voice of boys is coarse and deep.
4. Increased Activity of Sweat and Sebaceous Glands: During puberty the secretion of sweat glands and sebaceous glands (oil glands increase. Many young people get acne and pimples on the face at this time because of the increased activity of these glands in the skin.
5. Development of Sex Organs: At puberty, male sex organs like the testes and penis develop completely. The testes also begin to produce sperm. In girls, the ovaries enlarge and eggs begin to mature. Also, ovaries start releasing mature eggs.
6. Reaching Mental, Intellectual, and Emotional Maturity: Adolescents are more independent than before and are also self-conscious. Intellectual development takes place and they tend to spend considerable time thinking. Sometimes, however, an adolescent may feel insecure while trying to adjust to the changes in the body and mind.

SECONDARY SEXUAL CHARACTERS: The features which help to distinguish the male and female are called secondary sexual characters. The secondary sexual characteristics include breast development in girls and the growth of facial hair (i.e moustaches and beards) in boys. Boys also develop hair on their chests, both boys and girls have hair under the arms and in the pubic regions.

ROLE OF HORMONES IN INITIATING REPRODUCTIVE FUNCTION: The testes and ovaries secrete sex hormones. These hormones are responsible for the male and female secondary sexual characters. The sex hormones are under the control of hormones from the pituitary gland. The pituitary secretes many hormones, one of which makes ova mature in the ovaries and sperm form in the testes.

REPRODUCTIVE PHASE OF LIFE IN HUMANS: In females, the reproductive phase of life begins at puberty (10 to 12 years of age) and generally lasts till the age of approximately 45 to 50 years. The capacity for maturation and production of gametes lasts for a much longer time in males than in females.

HOW IS THE SEX OF THE BABY DETERMINED: The instruction for determining the sex of the baby is present in thin thread-like structures called chromosomes in the fertilized egg. There are two sex chromosomes in human beings X and Y. When a sperm containing the X chromosome fertilizes 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 fertilization, the zygote would develop into a male child.

HORMONES OTHER THAN SEX HORMONES: Apart from the pituitary, the testes and the ovaries, there are other endocrine glands in the body such as the thyroid, pancreas and adrenals. The thyroid gland produces thyroxine, the pancreas secretes insulin while adrenals secrete adrenalin.

ROLE OF HORMONES IN COMPLETING THE LIFE HISTORY OF INSECTS AND FROGS: Metamorphosis in insects is controlled by insect hormones. In a frog, it is controlled by thyroxine.

REPRODUCTIVE HEALTH: Reproductive health is defined as the state of physical, mental and social well-being of a person in all matters relating to the reproductive system at all stages of life.

Reaching the Age of Adolescence Class 8 Questions

Exercises

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

Ans.

S.No.	Name of Endocrine Gland	Hormone Secreted
1	Pituitary Gland	Growth hormone
2	Thyroid Gland	Thyroxine
3	Adrenal Gland	Adrenaline
4	Pancreas	Insulin
5	Testes	Testosterone
6	Ovaries	Estrogen

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

Ans. The hormones which are secreted by sex organs such as testes in males and ovaries in females are called sex hormones.

These hormones are named so because they control the sexual characteristics which help us to distinguish a boy and a girl.

These hormones are involved in the development and control of reproductive organs and the development of secondary sexual characteristics in boys and girls.

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.

Ans. (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.

Ans. (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.

Ans. (ii) chapati, dal, vegetables.

8. Write notes on:

(a) Adam’s apple.

Ans. During puberty, the voice box of boys grows in size. This growth can be seen as protruding part of the throat. This bulging part of the throat which results due to growth of the voice box is called Adam’s Apple. The growth of the voice box is responsible for the change in the voice of boys during puberty. The voice in boys gets deeper.

(b) Secondary sexual characters.

The sexual characteristics that are controlled by hormones, develop

during puberty and help in distinguishing between sexually mature males and females. These are not directly involved in the process of reproduction. The main secondary sexual characteristics that are found in males and females are as follows:

In males:

1. Growth of hair (moustaches and beard) and chest.
2. Shoulders broaden and the chest becomes wider.
3. Voice gets deeper.
4. Development of Adam’s Apple in front of the throat.
5. Growth of hair under armpits and in the pubic region (the region between thighs)

In females:

1. Breasts develop and grow in size.
2. Hips broaden and the region below the waist gets wider.
3. Growth of hair under armpits and in the pubic region (the region between thighs)
4. The voice becomes high-pitched or shrill.

(c) Sex determination in the unborn baby.

The sex of a baby is decided at the moment when fertilisation of the egg cell by the sperm cell takes place. The instruction for determining the sex of a baby is present inside a zygote in the form of thin thread-like structures called sex chromosomes. There are two types of sex chromosomes X and Y. A female has two X chromosomes while a male has one X and one Y chromosome.

1. If the sperm having a Y chromosome fertilizes the egg which has an X chromosome, the zygote formed will have a combination of XY sex chromosomes as a result the child born will be a boy.
2. If the sperm having an X chromosome fertilizes the egg which has an X chromosome, the zygote formed will have a combination of XX sex chromosomes as a result the child born will be a girl.

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

Across

3. Protruding voice box in boys
4. Glands without ducts
5. Endocrine gland attached to a brain
6. Secretion of endocrine glands
7. Pancreatic hormone
8. Female hormone

Down

1. Male hormone
2. Secretes thyroxine
3. Another term for teenage
4. Hormone reaches here through the bloodstream
5. Voicebox
6. Term for changes in adolescence

Ans

Across.

3. Adams Apple. 4. Endocrine. 7. Pituitary 8. Hormone 9. Insulin 10. Estrogen

Down

1. Testosterone 2. Thyroid 3. Adolescence 5. Target site 6. Larynx 7. Puberty. 

  That’s all about Reaching the Age of Adolescence Class 8 Question Answers. Hope it has helped. Do share your views about this post in the comment section below.