science - reaching the age of adolescence

Class 8 - Science

Reaching the Age of Adolescence


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 matures and is released by one of the ovaries once in about 28 to 30 days. 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. 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.

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Reaching the Age of Adolescence - Notes
1. Change in Body Shape
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2. Secondary Sexual Characters
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3. Development of Sex Organs
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4. Reproductive Health
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5. How is the Sex of the Baby Determined? Boy or Girl?
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6. Adolescence and Puberty
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7. Hormones other than Sex Hormones
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8. Reproductive Phase of Life in Humans
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