Reaching The Age Adolescence

The period of life between childhood and adulthood is called adolescence.

Adolescents are also called teenagers.

Adolescence begins around the age of 11 and lasts upto 18 or 19 years of age.

The most conspicuous change (clear visible change) in boys and girls during puberty is the sudden increase in height.

The long bones of arms and legs elongate and make a person tall.

The height of a person depends on the genes inherited from parents.

= 160 cm tall

As boys enter in puberty stage, their shoulders become broad and chest become wide.

During puberty, the region below the waist becomes wider in girls.

Voice box is also known as larynx.

Grown up girls have a smaller voice box than grown up boys.

The common name of the bulge (or projection) at the front of throat in grown up boys is Adam’s apple.

Sebaceous glands secrete oil.

Adolescence is a period of time in in one’s life when the brain has the greatest capacity for learning.

Sweat glands and sebaceous glands are present in the skin and causes pimples and acne.

(a) Sexual characteristics which are present in babies at birth are called primary sexual characters.

(b) Sexual characteristics which develop in mature boys and girls are called secondary sexual characters.

testes and ovaries function as endocrine glands as well as exocrine glands.

Endocrine glands are also known as ductless glands.

The secretion of endocrine glands is known as hormones.

(a) Estrogen (b) Testosterone

(a) Estrogen (b) Testosterone

The function of male sex hormone ‘testosterone’ is to develop secondary sexual characters in the boys.

The production of sex hormones ‘testosterone’ and ‘estrogen’ is under the control of another hormone secreted from an endocrine gland called pituitary gland.

The process in which the thickened uterus lining along with its blood vessels is removed from the body of a woman through vaginal bleeding is called menstruation.

Menarche comes earlier in the life of a woman.

At puberty (10 to 12 years of age).

At 45 to 50 years of age.

When a woman is preganant.

Women has a shorter reproductive phase of life.

XY combination of sex chromosomes produces a male child (or boy).

Sperm decides the sex of the child.

The legal age for the marriage is (a) 21 years for boys, and (b) 18 years for girls in our country.

Mother’s milk is a natural balanced food for infants.

The adolescent girls should take special care of personal hygiene during the time of menstrual flow.

(i) AIDS stands for Acquired Immunodeficiency Syndrome. (ii) HIV stands for Human Immunodeficiency virus.

HIV virus causes AIDS disease.

Pituitary gland is attached to the base of brain.

Pituitary gland secrets the growth hormone.

Iodine is needed continuously by thyroid gland to make thyroxine hormone.

The main symptom of goiter is a very big and bulging throat.

The deficiency of thyroxine hormone in body causes goiter.

Pancreas secretes insulin hormone.

The disease caused by the insufficient production of insulin hormone by pancreas is diabetes.

Adrenaline hormone prepares our body for action to face emergency situation like danger, fear, anger or excitement.

Adrenal gland secretes hormone called aldosterone that correct salt balance in the blood.

Aldosterone hormone is also secreted by adrenals.

Insulin hormone deficiency causes diabetes.

Thyroxine hormone is required for the metamorphosis of larvae (tadpoles) into adult frogs.

Insect hormone brings about metamorphosis in silk moth and changes caterpillar (larva) into adult silk moth.

(a) False, the estrogen hormone is a female hormone secreted by ovaries.

(b) False, menstruation stops in woman permanently around the age of 45 to 50 years.

(c) True, Man (father) is responsible for the sex of the body.

(d) True, the sex chromosomes in all the gametes (sperms) of a man are not identical.

(e) False, female gametes contain only X chromosomes.

(f) True, Sperm determines the sex of a child.

(g) False, each normal cell in our body contains 23 pair of chromosomes.

(h) False, it is a myth and not facts. A girl should not be allowed to work in the kitchen during menstruation.

(i) False, man is responsible for the sex of his child.

(j) False, Metamorphosis in insects (like silk moth) is brought about by insect hormone.

(a) puberty (b) hormones (c) faster (d) growing

(e) secondary (f) hormones (g) hormones (h) 23 ; 1

(i) sex (j) mother; child (k) fruits; vegetables (l) pituitary (m) thyroxine

The period of life, when the body undergoes changes, leading to reproductive maturity, is called adolescence. Adolescence begins around the age of 11 and lasts upto 18 or 19 years of age.

The changes which take place in boys are facial and body hair growth, voice deepens, testes start to make sperms etc.

The changes which take place in girls are breast grow, ovaries start to release egg, menstruation begins etc.

The age at which the sex hormones and gametes begin to be produced and the body and the girl become sexually matured is called puberty.

Generally girl attains puberty at an earlier age (11 to 12 years) in human beings.

(a) (i) There is a sudden increase in the height of both boys and girls during puberty.

(ii) Development of sex hormones also take place in both boys and girls during puberty.

(b) Changes that place only in boys during puberty are:

(i) Growth of hairs on chest.

(ii) Enlargement of voice box which leads to much deeper voice

(c) Changes that place only in girls during puberty are:

(i) Mammary gland enlargement

(ii) Menstruation.

The changes in body shape of boys during puberty occur in following ways:

(i) In boys, shoulder become broad and chest become wide.

(ii) In boys, the muscles of the body grow more prominently than in the girls.

The changes in body shape of girls during puberty occur in following ways:

(i) In girls, the region below the waist becomes wider.

(ii) Girls have high pitched voice.

In boys, the muscles of the body grow more prominently than in the girls. Whereas In girls, the region below the waist becomes wider. Thus, The changes in adolescent boys and girls are different.

Voice box is also known as larynx. In adolescent boys, voice box begins to grow and becomes large. Because of larger voice box, the voice becomes hoarse in grown up boys.

In girls, larynx is small in size due to which they have a high pitched voice.

In adolescent boys, voice box can be seen a protruding part of the throat called Adam’s apple. Grown up boys usually have an Adam’s apple.

When a boy reaches puberty, then his, voice box (also known as larynx). In adolescent boys, voice box begins to grow and becomes large. Because of larger voice box, the voice becomes hoarse in grown-up boys.

At puberty, male sex organs like the testes and penis develop completely. In girls, female sex organs like ovaries and uterus develop completely.

Many adolescent boys and girls may get acne and pimples on the face during puberty due to the increased activity of sebaceous glands and sweat glands in the skin.

Secondary sexual characteristics in mature boys:

(I) Voice becomes deeper (low pitched voice).

(II) Facial hair such as beard and moustache develop.

Secondary sexual characteristics in mature girls:

(I) Development of breast.

(II) Initiation of menstrual cycle.

Moustache, broad hips, beard, breast, Adam’s apple, wide shoulders and deeper voice are secondary sexual characteristics whereas ovaries, penis, vagina, uterus and testes are primary sexual characteristics.

Thyroid gland, adrenal gland and pituitary gland are endocrine gland as they secrete their secretion directly into the bloodstream. So, they are termed as ductless gland. While salivary gland, sweat gland and sebaceous gland (oil gland) secrete their secretions through ducts.

The onset of menstruation in human females (or girls) is termed menarche. It occurs at puberty (10 to 12 years of age).

The permanent stoppage of menstruation in women is termed menopause. It occurs at 45 to 50 years of age.

The two chromosomes that determine the sex of the unborn baby are called sex chromosomes named X chromosomes and Y chromosomes. A female has two X chromosomes, while a male has one X and one Y chromosome. The gametes (egg and sperm) have only one set of chromosomes. Thus, in females all the egg cells contain X chromosomes while in males, half sperm have X chromosomes and half sperms have Y chromosomes.

When a sperm containing X chromosome fertilizes the egg, the zygote would have XX 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.

Thus, father is responsible for the sex of the baby which is born.

(a) If X chromosome carrying sperm fuses with an egg cell carrying X chromosome at fertilization, then the zygote will have XX chromosomes and develop into a female child.

(b) If Y chromosome carrying sperm fuses with an egg cell carrying X chromosome at fertilization, then the zygote will have XY chromosomes and develop into a male child.

Hormones are chemical substances which coordinated the activities of the living organisms. Hormones are made and secreted by ductless glands called endocrine glands in the body. The hormones are released directly into the bloodstream and carried to the target site through blood circulatory system.

Hormones released by the reproductive organs like testes and ovaries and involved in the development of secondary sexual characteristics are called sex hormones. The two common sex hormones are testosterone and estrogen.

(i) The first occurrence of menstruation at puberty is called menarche.

(ii) The permanent stoppage of menstruation is termed menopause. It occurs at 45 to 50 years of age.

Menstruation is a process in which blood and mucous flows out every month through the vagina. Menstruation usually lasts for 3 to 5 days in human females. The frequency of menstrual cycle in human females is once in a month if egg is not fertilized.

The two chromosomes that determine the sex of the unborn baby are called sex chromosomes named X chromosomes and Y chromosomes.

A female has two X chromosomes, while a male has one X and one Y chromosome. The gametes (egg and sperm) have only one set of chromosomes.

The two chromosomes that determine the sex of the unborn baby are called sex chromosomes named X chromosomes and Y chromosomes. A female has two X chromosomes, while a male has one X and one Y chromosome. The gametes (egg and sperm) have only one set of chromosomes. Thus, in females all the egg cells contain X chromosomes while in males, half sperm have X chromosomes and half sperms have Y chromosomes.

When a sperm containing X chromosome fertilizes the egg, the zygote would have XX 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.

Thus, father is responsible for the sex of the baby which is born.

Various ways in which AIDS virus (HIV) can be transmitted are as follows:

● By sharing the syringes used for injecting drugs.

● It can be transmitted to an infant from the infected mother through her milk.

● It can be transmitted through sexual contact with a person infected with HIV.

AIDS is caused by a dangerous virus called HIV. This virus can be spread from infected person to healthy person by sharing the syringes used for injecting drugs.

Harmful effects of taking drugs are as follows:

(i) Drugs are addictive. If you take them once, you feel like taking them again and again.

(ii) They harm the body in the long run.

(iii) They ruin health and happiness.

Growth hormone is secreted by pituitary gland. Growth hormone is necessary for the normal growth of a person.

Iodine is needed continuously by thyroid gland to make thyroxine hormone. If people do not have enough iodine in their die, they will get goiter disease caused by lack of thyroxine. So, people are advised to use iodized salt in cooking food.

The deficiency of thyroxine hormone in adults causes a disease called goiter. The main symptom of disease is that the neck of the person suffering from Goitre appears to be swollen.

Insulin hormone lowers the blood sugar in humans. Pancreas gland secretes insulin hormone.

Insulin hormone is secreted by pancreas. The function of insulin hormone is to lower the blood sugar level.

There are two adrenaline glands in the body and are located on the top of the kidneys. Adrenaline glands secretes adrenaline hormone which helps the body to adjust to stress when one is very angry, embarrassed, or worried.

Six endocrine glands in the human body are as follows:

(i) Pituitary gland- It secretes growth hormone.

(ii) Thyroid gland- It secretes thyroxine hormone.

(iii) Pancreas- Secretes insulin hormone.

(iv) Adrenal gland- Secrete adrenaline hormone.

(v) Testes- Secrete testosterone.

(vi) Ovaries – Secrete estrogen.

(i) Pituitary gland is attached to the base of brain.

(ii) Thyroid gland is present in the neck.

(iii) Pancreas is just below the stomach in our body.

(iv) There are two adrenal glands in our body and are located on the top of the kidneys.

In frog, metamorphosis is controlled by thyroxine hormone and thyroxine production requires the presence of iodine. So, if the water in which tadpoles are growing does not contain sufficient iodine, the tadpole cannot become adult.

Acne is a skin condition marked by eruption of numerous red pimples on the face.

Pimples are small red spots on the face of a person. Many adolescent boys and girls may get acne and pimples on the face during puberty due to the increased activity of sebaceous glands and sweat glands in the skin.

The excess oil secreted by sebaceous glands and sweat secreted by sweat glands get collected in the tiny pores of the skin. The accumulation of oil, sweat and dead skin cells block the tiny pores in the face skin. Then, bacteria grow in the blocked skin pores causing swelling and redness of skin which leads to the formation of pimples.

(a) Rice and roti.

(b) Butter and ghee.

(c) Milk and pulses

(d) Fruits and vegetables.

Iron mineral is needed by our body as it builds our blood. Some of the iron rich foods are leafy vegetables, meat, jaggary, citrus, Indian gooseberry (amla).

Two practices which can be adopted by adolescents to maintain personal hygiene are given below:

(i) Adolescents boys and girls should take bath regularly.

(ii) Adolescent girls should take care of cleanliness of the body during the time of periods.

It is more necessary for adolescents to take bath regularly (at least once everyday) because increased activity of sweat glands sometimes makes the body smelly.

If personal hygiene (Cleanliness of body) is not maintained by adolescents, it will increase the chances of catching bacterial infection.

The various ways in which early marriage and motherhood is harmful to the girls are as follows:

(i) Early marriage and motherhood cause health problems in the mother and the child.

(ii) It reduces curtails employment opportunities for the young woman.

(iii) It may cause mental agony as she is not ready for responsibilities of motherhood.

Changes take place in boys during puberty:

(i) The most conspicuous change (clear visible change) in boys during puberty is the sudden increase in height.

(ii) Shoulder become broad and chest become wide.

(II) Muscles of the body grow more prominently than in the girls.

(iii) Voice deepens in boys. It becomes low pitched voice.

(iv) Many adolescent boys and girls may get acne and pimples on the face during puberty due to the increased activity of sebaceous glands and sweat glands in the skin.

(v) Hair grow on the face in the form of moustache and beard, and on the chest.

(vi) Hair grows under the arms and in the region above the thighs or the pubic region.

(vii) Testes and penis become larger.

(viii) Testes start to make sperm.

Changes which occur in girls during puberty are:

(i) Rapid increase in height.

(ii) The region below the waist becomes wider.

(iii) Hair grow in armpits and in pubic regions between the thighs.

(iv) The ovary enlarges and starts producing matured eggs.

(v) Menstruation begins.

(vi) Have high pitched voice.

(vii) Development and enlargement of breast.

Sexual characteristics which are present in babies at birth are called primary sexual characters. They include internal and external sex organs which are present in babies at the time of their birth. The primary sexual characteristics in males are Testes and penis.

The primary sexual characteristics in females are ovaries and uterus.

Sexual characteristics which develop in mature boys and girls are called secondary sexual characters. These changes are controlled by hormones.

Hormones released by the reproductive organs like testes and ovaries and involved in the development of secondary sexual characteristics are called sex hormones. The two common sex hormones are testosterone and estrogen.

Secondary sexual characteristics in males are:

(i) Hair grow on the face in the form of moustache and beard, and on the chest.

(ii) Testis grow and starts producing sperms in males.

Secondary sexual characteristics in females are:

(i) Milk secreting glands or mammary glands develop inside the breasts.

(ii) Initiation of menstruation.

(iii) Ovary enlarges and starts producing matured eggs.

Menstrual cycle begins when a girl reaches the age of puberty. At this age, ovaries release sex hormones in the blood which cause maturation of ova in ovaries. One mature egg or ovum is released by one of the ovaries once in about 28 to 30 days. This is termed as ovulation. Before ovulation, uterus prepares itself to receive the fertilized egg. The inner lining of the uterus becomes thick and soft with lots of blood capillaries in it.

If the ovum does not get fertilized, then the inner lining of uterus is not required and hence it breaks down and comes out through the vagina in the form of a bleeding called menstruation.

Menstruation occurs once in about 28 to 30 days and it usually lasts for 3 to 5 days.

A gland which secretes its product into a duct or tube is called exocrine gland. Salivary gland and sweat gland are examples of exocrine glands.

Endocrine glands are also known as ductless glands as they release their secretion directly into the bloodstream. Thyroid gland, adrenal gland and pituitary gland are endocrine glands.

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

The important conditions necessary to maintain good reproductive health during adolescence are:

(i) It is necessary to eat balanced diet during adolescence.

(ii) It is necessary to maintain personal hygiene during adolescence.

(iii) It is necessary to take adequate physical exercise during adolescence.

(iv) It is necessary to avoid taking any drugs during adolescence.

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 first occurrence of menstruation at puberty is called menarche. It is the beginning of the reproductive life of a girl.

The sex of a child is determined by the presence of a Y chromosomes in sperm.

The legal age for the marriage is 21 years for boys, and 18 years for girls in our country.

The legal age for the marriage is 21 years for boys, and 18 years for girls in our country.

Adolescents need balanced diet for normal growth and development of the body. A balanced diet means that the meals include proteins, carbohydrates, fats and vitamins in requisite proportions. Our Indian meal of roti /rice, dal(pulses) and vegetables is a balanced meal.

Adolescents should be careful about what they eat because proper diet is needed for the rapid growth taking place in their body.

AIDS is caused by a dangerous virus called HIV. This virus can be spread from infected person to healthy person by sharing the syringes used for injecting drugs.

Thyroxine hormone is required for the metamorphosis of larvae (tadpoles) into adult frogs. Iodine is needed continuously by thyroid gland to make thyroxine hormone. If people do not have enough iodine in their die, they will get goiter disease caused by lack of thyroxine. So, people are advised to use iodized salt in cooking food.

Adrenaline hormone secreted by adrenal glands whereas pituitary gland secretes growth hormone.

Testosterone is a male sex hormone which is secreted by testes. This hormone brings changes in boys such as growth of facial hair.

Estrogen and testosterone are sex hormones which involved in the development and control of the reproductive organs and secondary sexual characteristics.

Pituitary gland is attached to the base of brain. It secretes growth hormone.

Iodine is needed continuously by thyroid gland to make thyroxine hormone. If people do not have enough iodine in their die, they will get goiter disease caused by lack of thyroxine. So, people are advised to use iodized salt in cooking food.

Ovaries, vagina and fallopian tubes are organs of female reproductive system whereas seminal vesicles are part of male reproductive system.

During puberty, the region below the waist becomes wider in girls.

There are two conditions which can lead to menstruation in a 21-year-old woman during ovulation. These are: (i) Blocked oviduct and, (ii) sperms not available for fertilization.

Growth hormone is secreted by pituitary gland. Growth hormone is necessary for the normal growth of a person.

Adrenaline hormone prepares our body for action to face emergency situation like danger, fear, anger or excitement.

Insulin hormone is secreted by pancreas. The function of insulin hormone is to lower the blood sugar level.

Many adolescent boys and girls may get acne and pimples on the face during puberty due to the increased activity of sebaceous glands and sweat glands in the skin.

(a) (i) It is known as menstruation in scientific terms.

(ii) It is known as periods in everyday language.

(b) The process of menstruation begins at Puberty.

(c) The onset of menstruation in human female signify that the reproductive system of human female has started working.

(d) In the beginning of pregnancy, the process of menstruation stops temporarily but starts again.

(e) When menstruation stops permanently, it is termed menopause.

(a) Due to blocked oviducts of the woman, the ovum released by her ovary cannot meet the sperm and get fertilized.

(b) In vitro fertilization technique is used to help those couples in having babies who can produce sperms and ovum but fertilization does not take place inside the woman’s body due to blocked oviducts.

If X chromosome carrying sperm fuses with an egg cell carrying X chromosome at fertilization, then the zygote will have XX chromosomes and develop into a female child.

In the other case, if Y chromosome carrying sperm fuses with an egg cell carrying X chromosome at fertilization, then the zygote will have XY chromosomes and develop into a male child. Thus, father is responsible for the sex of the unborn child.

(a) Raj Kumar and his wife Sunita have been blessed with a baby girl. It means, X chromosome has been contributed by raj Kumar.

(b) Sunita also contributed X chromosome.

(c) Kripa Shanker and his wife Vimla have been blessed with a baby boy, thus, kripa shanker contributed Y chromosome.

(d) Vimla contributed X chromosome.

W is Pancreas ; X is Insulin ; Y is Diabetes ; Z is Diabetic.

(a) (i) iodine (ii) Thyroxine (ii) Metamorphosis

(b) Iodine is needed continuously by thyroid gland to make thyroxine hormone. If people do not have enough iodine in their die, they will get goiter disease caused by lack of thyroxine. So, people are advised to use iodized salt in cooking food.