Chapter 10 - Reaching the Age of Adolescence

ADOLESCENCE AND PUBERTY

• Adolescence: It is the period of life, when the body undergoes changes, leading to reproductive maturity.
• It begins around the age of 11 and lasts up to 18 or 19 years of age. Adolescents are also called TEENAGERS.
• In girls, the adolescence begins a year or two earlier than boys, the period of adolescence varies from person to person.
• Puberty : The period of adolescence during which an adolescent reaches sexual maturity and becomes capable of reproduction.

CHANGES AT PUBERTY

• Increase in Height: The most conspicuous change is sudden increase in height of person during puberty due to elongation of the bones of arms and legs. Initially girls grow faster than boys; both reach maximum height by the age of around 18 year.

• Changes in body shape : In boys, the shoulders generally broaden and muscles of the body grow more prominently than in the girls.

For girls, the region below the waist becomes wider and less growth of muscles.

• Voice change : Voice box or larynx in boy develops into larger in size.

It can be seen as protruding part of throat as ADAM'S APPLE.

In girls, larynx is hardly visible due to smaller size in growth. Boys have deep voice where as girls have high pitch voice.

• Increased activity of sweat and sebaceous glands: During puberty, there is increase in the secretion of sweat glands and sebaceous glands which may lead to appearance of acne and pimples.

• Development of sex organ : At puberty, male sex organs like testes and penis develop completely and begin to produce sperms. In girls, the ovaries enlarge and start releasing eggs or ova.

• Reaching mental, intellectual and emotional maturity : During adolescence they tend to think more. Feel insecure when while trying to adjust to the changes in mind and body. During adolescence, a person’s brain has greatest capacity for learning.

SECONDARY SEXUAL CHARACTERS

• A character which develops during adolescence and helps to distinguish the male from female are known as secondary sexual characters. Some of these characters are as listed below;

SECONDARY SEXUAL CHARACTERS
FEMALE	MALE
Begins to develop breasts	Growth of facial hair i.e. moustaches, beard
Hair under arms, pubic region	Hair on chest, arm pit, pubic region

• Hormones are chemical substances secreted by endocrine system/ endocrine glands (Ductless gland i.e. endocrine glands release hormone directly into blood stream to reach particular body part/TARGET SITE).
• Hormones control the changes during adolescence. Pituitary gland (found attached to brain) secretes hormone which in turn control the production of hormone from other endocrine glands.

REPRODUCTIVE PHASE OF LIFE IN HUMANS

• Adolescents become capable of reproduction when their testes and ovaries begin to produce gametes.
• In females, reproductive phase of life begins at puberty (10-12 years of age and generally lasts till the age of approx 45-50 years).
• Ova mature and is released by one of the ovaries once in about 28-30 days. Fertilized egg develops pregnancy.
• Unfertilized egg along with the thickened lining of uterus and blood vessels are shed off in the form of bleeding in women once in about 28-30 days is termed MENSTRUATION.
• Initial menstrual flow begins at puberty and is termed MENARCHE.
• Stoppage of menstrual cycle at 45-50 years of age is called MENOPAUSE.

HOW IS THE SEX OF THE BABY DETERMINED

• Instruction for determining the sex of a baby is present in the chromosome of fertilized egg (zygote).Human have 23 pairs of chromosomes including two sex chromosome (X and Y) in the nucleus of their cells.
• Females have two X chromosomes and males have one X and one Y chromosome.
• Unfertilized egg has one X chromosome. Sperm may have one X chromosome or Y chromosome. Therefore, sex chromosomes of the father determine the sex of the unborn baby.

HARMONES OTHER THAN SEX HARMONE

ROLE OF HORMONES IN INITIATING REPRODUCTIVE FUNCTION

ROLE OF HORMONES IN COMPLETING THE LIFE HISTORY OF INSECTS AND FROGS

Metamorphosis

• The change from larva to adult is known as metamorphosis.
• In insects it is controlled by insect hormones.
• In frog, thyroid produce thyroxin hormone for metamorphosis (change from tadpoles to adult frog).
• Sufficient iodine in the water is also an important for metamorphosis.

REPRODUCTIVE HEALTH

• The physical and mental well being of an individual is regarded as health.
• To keep the body healthy, every human being at any age needs to have a balanced diet, must observe personal hygiene and undertake adequate physical exercise.

Nutritional needs of the adolescents

• Adolescence is a stage of rapid growth and development. So, balanced diet comprising proteins, carbohydrates, fats, minerals and vitamins in requisite quantity is essential.
• Iron builds blood. Iron rich food such as leafy vegetables, jiggery, meat, citrus, Indian gooseberry is good for adolescent.

Personal hygiene

• Take bath once a day. It is more necessary for adolescents due to increased activity of sweat glands which may lead to smelly body.
• All parts of body should be washed and cleaned every day.

Physical exercise :

• Adolescents should take walk, exercise.
• Play outdoor games in fresh air to keep them fit and healthy.

SAY NO TO DRUGS

• Shouldn't use drugs for relief until and unless doctor prescribes.
• If taken once, you will feel like taking them again and again which will ruin health and happiness.
• Dangerous virus like HIV can be transmitted through sexual contact with infected person or by sharing the syringes used by infected person for injecting drug