8th science biology Reaching The age of Adolescence

 

 Science

ICSE/ CBSE Notes

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By Er. Amit Singh

10-Reaching The age of Adolescence

Adolescence

• The phase of life, when the body undergoes radical changes, leading to reproductive maturity, is known as adolescence
• After adolescence comes the adulthood.

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• Adolescence normally begins around the age of 11 and lasts up to 18 or 19 years of the age. However, the phase of adolescence varies from person to person.
• Starting from thirteen (13) to nineteen (19), ‘teen’ is suffix and common in every number; therefore, adolescents are also known as ‘teenagers.’
• In girls, adolescence phase may begin one year or two years earlier than the boys.

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Puberty

• During the adolescence phase, the human body undergoes several changes, which are marked as the onset of puberty.
• The most important change, which marks puberty, is that the boys and the girls become capable of reproduction.
• Puberty, however, ends when an adolescent phase attains reproductive maturity.

Sex Determination of baby 

• The sex of the baby depends on the chromosomes presents in the fertilized egg.
• Chromosomal sex is determined at fertilization.
• Sex is influenced by genetic and environmental factors.
• Females (generally XX) do not have a Y chromosome.
• Formation of male or female reproductive structures depends on
•  Gene action.
•  Interactions within the embryo.
•  Interactions with other embryos in the uterus.
•  Interactions with the maternal environment.

Balanced diet

1-fruit
2-vegetables, legumes and beans
3-cereals (including breads, rice, pasta and noodles), preferably wholegrain
4-lean meat, fish, poultry and/or alternatives
5milks,cheeses and/or alternatives (children under 2 should have full-fat milk, but older children and adolescents can have reduced-fat varieties)

6- Taking proper exercise and playing games.

Personal Hygiene

 Endocrine System of Humans

Hormones

• Hormones are chemical messengers that are secreted directly into the blood, which carries them to organs and tissues of the body to exert their functions
• The hormones are produced in special organs which are called Endocrine glands.
• Endocrine glands have no ducts.
• Endocrine glands glands are also called ductless glands.

Function of Hormones

• Hormones help in maintaining a constant environment inside the body.
• It adjusting the amount of salt and water in our body tissues, sugar in the blood and salt in the sweat.
• It produce long term changes such as a child growth and sexual maturation.
• It expressing the emotion such as fear,anger ,happiness etc.

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