Reaching the age of adolescence by gaurav ghankhede
- 1. 10. REACHING THE AGE OF ADOLESCENCE
- 2. 1. ADOLESCENCE AND PUBERTY • Growing up is a natural process. 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. Since this period covers ‘teens’ (13 to 18 or 19 years of age), the period of adolescence may begin a year or two earlier than in boys. Also, the period of adolescence varies from
- 3. • The human body undergoes several changes during adolescence. These changes mark the onset of puberty. • The most important change which marks puberty is that boys and girls become capable of reproduction. Puberty ends when an adolescent reaches reproductive maturity.
- 4. 2. CHANGES AT PUBERTY- 1) INCREASE IN HEIGHT • The most conspicuous change during puberty is the sudden increase in height. At this time the long bones, that is, the bones of the arms and the legs elongate and make person tall. • Girls grow faster than boys but by about 18 years of age, both reach their maximum height. • The following chart gives the average rate of growth in height of boys and girls.
- 5. Age in years % of full height Boys Girls 8 72% 77% 9 75% 81% 10 78% 84% 11 81% 88% 12 84% 91% 13 88% 95% 14 92% 98% 15 95% 99% 16 98% 99.5% 17 99% 100% 18 100% 100% Full height= Present height/ % of full height at this
- 6. 2) CHANGE IN BODY SHAPE • When boys have entered the age of puberty when shoulders generally broaden as a result of growth. • In girls, the region below the waist becomes wider. • In boys, the muscles of the body grow more prominently than in the girls. • Thus, changes occurring in adolescent boys and girls are different.
- 7. 3) VOICE CHANGE • At puberty, the voice box or the larynx begins to grow. Boys develop larger voice boxes. The growing voice box in boys can be seen as a protruding part of the throat called Adam’s apple. • In girls, the larynx is hardly visible from the outside because of its small size. Generally, girls have a high pitched voice, whereas boys have a deep voice. In adolescent boys, sometimes, the muscles of the growing voice box go out of control and the voice
- 8. ADAM’S APPLE
- 9. 4) INCREASED ACTIVITY OF SWEAT AND SEBACEOUS GLANDS • During puberty the secretion of sweat glands and sebaceous glands (oil glands) increases. Many young people get acne and pimples on the face at this time because of the increased activity of these glands in the skin. • A few glands such as sweat glands, oil glands and salivary glands release their secretions through ducts. Endocrine glands release hormones directly into the
- 10. 5) DEVELOPMENT OF SEX ORGANS • At puberty, male sex organs like the testes and penis develop completely. The testes also begin to produce sperms. • In girls, the ovaries enlarge and eggs begin to mature. Also ovaries start releasing mature eggs.
- 11. 6) REACHING MENTAL, INTELLECTUAL AND EMOTIONAL MATURITY • Adolescence is also a period of change in a person’s way of thinking. Adolescents are more independent than before and are also self conscious. • Intellectual development takes place and they tend to spend considerable time thinking. In fact, it is often the time in one’s life when the brain has the greatest capacity for learning. Sometimes, however, an adolescent may feel insecure while trying to adjust to
- 12. 3. SECONDARY SEXUAL CHARACTERS • In girls, breasts begin to develop at puberty and boys begin to grow facial hair, that is, moustaches and beard. As these features help to distinguish the male from the female they are called secondary sexual characters. • Boys also develop hair on their chest. In both, boys and girls, hair grows under the arms and in the region above the thighs or the pubic region.
- 13. 3. SECONDARY SEXUAL CHARACTERS • The changes which occur at adolescence are controlled by hormones. Hormones are chemical substances. These are secretions from endocrine glands, or endocrine system. The male hormone or testosterone begins to be released by the testes at the onset of puberty. This causes changes in boys. • Once puberty is reached in girls, ovaries begin to produce the female hormone or estrogen which
- 14. 3. SECONDARY SEXUAL CHARACTERS • Milk secreting glands or mammary glands develop inside the breasts. The production of these hormones is under the control of another hormone secreted from an endocrine gland called pituitary gland.
- 15. 4. ROLE OF HORMONES IN INITIATING REPRODUCTIVE FUNCTION • Endocrine glands release hormones into the bloodstream to reach a particular body part called target site. The target site responds to the hormone. There are many endocrine glands or ductless glands in the body. • The testes and ovaries secrete sex hormones. male and female secondary sexual characters. Further, the sex hormones are under the control of hormones from the pituitary gland The pituitary secretes many
- 16. THE ONSET OF PUBERTY IS CONTROLLED BY HORMONES Hormones from pituitary simulate testes and ovaries to release testosterone (in male) and estrogen (in female) Released in the blood stream and reach parts of the body (target site) Simulate changes in the body at onset of puberty
- 17. 5. REPRODUCTIVE PHASE OF LIFE IN HUMANS • Adolescents become capable of reproduction when their testes and ovaries begin to produce gametes. The capacity for maturation and production of gametes lasts for a much longer time in males than in females. • 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 ova begin to mature with the onset of puberty. One ovum
- 18. 5. REPRODUCTIVE PHASE OF LIFE IN HUMANS • During this period, the wall of the uterus becomes thick so as to receive the egg, in case it is fertilised and begins to develop. This results in pregnancy. If fertilisation does not occur, the released egg, and the thickened lining of the uterus along with its blood vessels are shed off. This causes bleeding in women which is called menstruation. Menstruation occurs once in about 28 to 30 days. The first menstrual flow begins at puberty and is termed menarche.
- 19. 5. REPRODUCTIVE PHASE OF LIFE IN HUMANS • At 45 to 50 years of age, the menstrual cycle stops. Stoppage of menstruation is termed menopause. Initially, menstrual cycle may be irregular. It take some time to become regular. • Menstrual cycle is controlled by hormones. The cycle includes the maturation of the egg, its release, thickening of uterine wall and its breakdown if pregnancy does not occur. In case the egg is fertilised
- 20. 6. DETERMINATION OF SEX OF BABY • Inside the fertilised egg or zygote is the instruction for determining the sex of the baby. This instruction is present in the thread-like structures, called chromosomes in the fertilised egg. • chromosomes are present inside the nucleus of every cell. All human beings have 23 pairs of chromosomes in the nuclei of their cells. Two chromosomes out of these are the sex chromosomes, named X and Y. A female has two X chromosomes, while a male has one X and one Y
- 21. 6. DETERMINATION OF SEX OF BABY • But sperms are of two kinds. One kind has an X chromosome, and the other kind has a Y chromosome. • When a sperm containing X chromosome fertilises 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 fertilisation, the zygote would develop into a male child.
- 22. SEX DETERMINATION IN HUMANS
- 23. 7. HORMONES OTHER THAN SEX HORMONES • Goitre disease is a disease of thyroid gland. Because thyroid gland does not produce the hormone thyroxine. • When pancreas are not able to produce hormone insulin in sufficient quantities, diabetes is caused. • adrenal glands secrete hormones which maintain the correct salt balance in the blood. Adrenals also produce the hormone adrenalin. Thyroid and adrenals secrete their hormones when they receive orders from the pituitary through its hormones. Pituitary also secretes growth hormone which is necessary for the normal growth of a
- 24. POSITION OF ENDOCRINE GLANDS IN THE HUMAN BODY
- 25. 8. 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, the hormone produced by thyroid. Thyroxine production requires the presence of iodine in water. If the water in which the tadpoles are growing does not contain sufficient iodine, the tadpoles cannot become adults.
- 26. 9. REPRODUCTIVE HEALTH • The physical and mental well being of an individual is regarded as an individual’s health. To keep the body healthy, every human being, at any age, needs to have a balanced diet. The person must also observe personal hygiene and undertake adequate physical exercise.