CBSE Class 8 Science Chapter 10: Reaching the Age of Adolescence - NCERT Solutions

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NCERT Solutions PDF Class 8 PDF

This chapter delves into the crucial period of human development known as adolescence, covering the biological and physiological changes that occur during puberty. Students will explore the role of endocrine glands and hormones in these transformations, including the onset of secondary sexual characteristics and the process of menstruation in females. The NCERT Solutions for Chapter 10 of Class 8 Science provide clear explanations and detailed answers to exercises, helping students grasp concepts like hormones, adolescence, puberty, and reproductive maturity. These solutions are designed to aid in understanding the complexities of physical and emotional changes during this life stage, making them an excellent resource for exam preparation and revision.

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Quick info

BoardCBSE
ClassClass 8
SubjectScience
Session2026
LanguageEnglish
TypeNCERT Solutions
ChapterChapter 10

Chapter summary

Chapter 10, 'Reaching the Age of Adolescence,' focuses on the transformative period of puberty. The NCERT Solutions explain the biological changes, including the role of hormones secreted by endocrine glands, the development of secondary sexual characteristics in boys and girls, and the process of menstruation. The solutions also define adolescence and provide a table of endocrine glands and their respective hormones, aiding students in understanding the physiological shifts leading to reproductive maturity.

Learning outcomes

  • Understand the definition and duration of adolescence.
  • Identify the role of hormones in bringing about bodily changes during puberty.
  • Explain the process of menstruation in females.
  • List and describe the common and sex-specific changes occurring during puberty.
  • Identify key endocrine glands and the hormones they secrete.

Topics covered

Paper topics

  • Adolescence
  • Puberty
  • Hormones
  • Endocrine Glands
  • Menstruation
  • Secondary Sexual Characteristics
  • Changes in Boys
  • Changes in Girls
  • Growth Hormones
  • Thyroxine
  • Adrenalin
  • Insulin

Important topics

  • Understanding Adolescence and Puberty
  • Role of Hormones in Bodily Changes
  • Process of Menstruation
  • Secondary Sexual Characteristics
  • Endocrine Glands and Hormones Table

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Questions and Solutions

Question 1

What is the term used for secretions of endocrine glands responsible for changes taking place in the body?
Solution: The secretions of endocrine glands that are responsible for initiating and regulating the various changes occurring in the body during different life stages, especially during puberty, are called hormones. Hormones act as chemical messengers, carrying signals from the endocrine glands to target cells or organs throughout the body to bring about specific responses.

Question 2

Define adolescence.
Solution: Adolescence is the transitional stage of human development that marks the period between childhood and adulthood. It is characterized by significant physical, psychological, and social changes, leading to reproductive maturity. In humans, this phase typically begins around the age of 11 years and extends up to 18 or 19 years of age.

Question 3

What is menstruation? Explain.
Solution: Menstruation is a natural biological process that occurs in females of reproductive age. With the onset of puberty, the ovaries begin to mature and release an egg (ovum) approximately once every 28 to 30 days. Simultaneously, the lining of the uterus thickens to prepare for the potential implantation of a fertilized egg. If fertilization does not occur, the thickened uterine lining, along with the unfertilized egg and blood, is shed and expelled from the body. This shedding results in bleeding, which is known as menstruation. This cycle repeats roughly every 28 to 30 days.

Question 4

List changes in the body that take place at puberty.
Solution: Puberty is a phase of rapid growth and development where the body undergoes numerous changes, leading to sexual maturity. Both boys and girls experience common changes, as well as some sex-specific ones:

Common Changes in Boys and Girls:

  • A sudden and significant increase in overall height.
  • Alterations in body shape, leading to a more mature physique.
  • Changes in voice: in boys, the voice typically deepens and becomes harsher, while in girls, it tends to become higher-pitched.
  • Increased activity of sweat glands and sebaceous (oil) glands, which can sometimes lead to skin issues like acne.
  • The reproductive organs begin to mature and become functional.
  • The appearance of secondary sexual characteristics, which are physical traits that distinguish males and females beyond the reproductive organs.

Specific Changes in Boys:

  • Development of facial hair, such as a beard and moustache.
  • Growth of hair in the armpits, chest, and pubic regions.
  • Voice becomes noticeably deeper.
  • Muscles develop, leading to broader shoulders and a more muscular build.
  • An increase in body weight as muscle mass and bone density increase.

Specific Changes in Girls:

  • Development and enlargement of breasts.
  • Growth of hair in the armpits and pubic regions.
  • The hips broaden, and the pelvic region widens, preparing for potential childbirth.
  • Initiation of the menstrual cycle, marking the onset of reproductive capability.
  • Deposition of fat around the hips and thighs, contributing to a curvier body shape.

Question 5

Prepare a Table having two columns depicting names of endocrine glands and hormones secreted by them.
Solution: Here is a table listing some key endocrine glands and the primary hormones they secrete:
Endocrine Gland Hormone Secreted
Pituitary Growth Hormone
Thyroid Thyroxine
Adrenal Adrenalin
Pancreas Insulin
Testes (in males) Testosterone
Ovaries (in females) Oestrogen & Progesterone

Common mistakes

  • Confusing adolescence with puberty.
  • Not understanding the cyclical nature of menstruation.
  • Incomplete listing of changes during puberty.
  • Misidentifying endocrine glands or their secreted hormones.

Revision tips

  • Create flashcards for endocrine glands and their hormones.
  • Draw diagrams illustrating the changes during puberty for boys and girls.
  • Explain the concept of menstruation in your own words to a friend.
  • Review the definitions of adolescence and puberty to ensure clarity.

Practice MCQs

Q1. What is the primary role of hormones in the body?

Q2. Adolescence is the period of life leading to:

Q3. Which of the following is a common change during puberty for both boys and girls?

Q4. What is menstruation?

Q5. Which endocrine gland secretes Insulin?

Frequently asked questions

What is adolescence according to NCERT Class 8 Science?

Adolescence is defined as the period of life when the body undergoes significant changes leading to reproductive maturity. It typically begins around the age of 11 and continues up to 18 or 19 years of age.

What are hormones and what is their function?

Hormones are secretions from endocrine glands that are responsible for the changes occurring in the body. They act as chemical messengers, transporting signals from one cell or gland to another.

What is menstruation and when does it occur?

Menstruation is the process where the thickened lining of the uterus, along with an unfertilized egg and blood, is shed from the female body. This occurs approximately once every 28 to 30 days if pregnancy does not happen.

List some common changes that happen during puberty.

Common changes during puberty include a sudden increase in height, changes in body shape, voice changes (deepening in boys, higher pitch in girls), increased activity of sweat and sebaceous glands, and the maturation of reproductive organs.

Which endocrine glands and hormones are covered in this chapter?

The chapter covers the Pituitary gland (Growth Hormones), Thyroid gland (Thyroxine), Adrenal gland (Adrenalin), Pancreas (Insulin), Testes (Testosterone), and Ovaries (Oestrogen & Progesterone).

Important links

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