NCERT Solutions Class 8 Science Chapter 7 Reaching the Age of Adolescence

Reaching the Age of Adolescence - Class 8 Notes: Comprehensive Guide

Introduction to Adolescence

Adolescence is the period of life when a child transitions into adulthood. This phase is marked by significant physical, mental, and emotional changes, collectively known as puberty. Understanding these changes can help adolescents navigate this transformative stage more smoothly.

Physical Changes During Puberty

Increase in Height

A noticeable increase in height is one of the most conspicuous changes during adolescence. The long bones in the arms and legs elongate, resulting in a sudden spurt in growth. This is more evident with these stages:

• Boys and girls experience increased height at different rates.

• By approximately 18 years, both reach their maximum height.

Change in Body Shape

Adolescence brings about distinctive changes in body shape for boys and girls:

• Boys develop broader shoulders and wider chests.

• Girls see a widening of the region below the waist.

Hormonal Changes During Adolescence

Role of Hormones

Hormones play a pivotal role in driving the changes seen during adolescence. These chemical substances are secreted by endocrine glands and have various target sites within the body.

Importance of the Pituitary Gland

The pituitary gland, often termed the "master gland," secretes hormones that stimulate the testes and ovaries. This results in the production of sex hormones like testosterone in boys and oestrogen in girls.

Development of Reproductive Organs

• Boys: The testes and penis develop completely, and the production of sperms begins.

• Girls: The ovaries enlarge, eggs begin to mature, and the release of mature eggs starts.

Mental, Intellectual, and Emotional Maturity

Adolescents experience profound changes in their way of thinking and emotional responses. Intellectual development is heightened, often marked by increased curiosity and learning capacity. Emotional maturity also evolves, although it may come with periods of insecurity and self-consciousness.

Nutritional Needs of Adolescents

Importance of a Balanced Diet

A balanced diet is critical during adolescence to support rapid growth and development.

Essential Nutrients for Growth and Development

• Proteins: Crucial for tissue building and repair.

• Carbohydrates: Primary source of energy.

• Fats: Necessary for long-term energy storage.

• Vitamins and Minerals: Aid in various body functions.

Personal Hygiene and Physical Health

Importance of Daily Hygiene

Maintaining personal hygiene is particularly important during adolescence due to increased activity of sweat and sebaceous glands.

Physical Exercise and Health

Regular physical activity helps keep the body fit and healthy. Adolescents should engage in outdoor games, walking, or exercises daily.

Myths and Taboos

Adolescents often encounter myths and taboos concerning body changes. Here are a few to debunk:

1. A girl cannot get pregnant simply by looking at boys during menstruation.

2. The mother is not responsible for the sex of the child.

Voice Changes and Skin Conditions

Changes in Voice

• Boys: The voice box, or larynx, grows, leading to a deeper voice and the formation of an Adam's apple.

• Girls: The larynx remains small, leading to a high-pitched voice.

Increased Activity of Sweat and Sebaceous Glands

Heightened gland activity can cause acne and pimples due to increased oil secretion.

Reproductive Health and Safe Practices

Reproductive Phase of Life

• Females: Reproductive phase begins around 10-12 years and ends approximately at 45-50 years.

• Menstrual Cycle: Controlled by hormones, it includes the maturation and release of an egg every 28-30 days.

How is the Sex of a Baby Determined?

Role of Chromosomes

Inside the fertilised egg, chromosomes determine the sex of the baby. Females have two X chromosomes, while males have one X and one Y chromosome. The sperm determines whether the offspring will be male (XY) or female (XX).

Importance of Avoiding Drugs

Adolescents are at a critical stage of development and should avoid drug use. Drugs are addictive, can harm the body, and may lead to serious health conditions like HIV/AIDS.

Conclusion and Final Notes

Reaching the age of adolescence is a significant phase filled with various changes that pave the way for adulthood. Understanding these changes and adopting healthy practices can help adolescents navigate this period more effectively.