Introduction
The period of life when the body undergoes several physical, mental, and emotional changes is known as adolescence. This stage marks the transition from childhood to adulthood. In humans, adolescence usually begins around 11 years and ends by 18–19 years.
Adolescence and Puberty
- Adolescence is the age group between childhood and adulthood.
- Puberty is the stage when the body starts showing changes that lead to reproductive maturity.
Puberty is a part of adolescence and is controlled by hormones.
Changes at Puberty
1. Increase in Height
- Sudden growth in height occurs during adolescence.
- Long bones of arms and legs grow rapidly.
2. Change in Body Shape
- Boys develop broader shoulders and more muscle mass.
- Girls develop wider hips and breasts.
3. Voice Change
- Voice box or larynx grows.
- Boys develop a deep voice due to a prominent Adam’s apple.
- Girls’ voice becomes high-pitched but no visible Adam’s apple appears.
4. Hair Growth
- Hair appears in armpits and pubic region.
- Boys also grow facial hair.
5. Increased Activity of Sweat and Oil Glands
- Leads to body odour and pimples (acne).
6. Development of Sex Organs
- Testes in boys and ovaries in girls begin to function.
- Reproductive capability develops.
Hormones
Hormones are chemical substances that control growth, development, and functioning of the body.
They are released directly into the bloodstream by endocrine glands.
Endocrine Glands and Their Functions
Pituitary Gland
- Known as the master gland
- Controls growth and other endocrine glands
Thyroid Gland
- Produces thyroxine
- Controls metabolism
- Requires iodine for proper functioning
Pancreas
- Produces insulin
- Controls blood sugar level
Adrenal Glands
- Produce adrenaline
- Helps the body respond to stress and emergencies
Testes
- Produce testosterone
- Responsible for male secondary sexual characters
Ovaries
- Produce oestrogen
- Responsible for female secondary sexual characters
Sex Hormones
- Testosterone: Male hormone
- Oestrogen: Female hormone
These hormones cause physical and reproductive changes during puberty.
Reproductive Phase of Life in Humans
- In females, the reproductive phase begins with menarche (first menstrual cycle).
- It ends with menopause.
- In males, sperm production starts at puberty and continues throughout life.
Menstrual Cycle
The menstrual cycle is a monthly cycle of changes in the female body.
- It lasts about 28 days
- Involves the release of an egg (ovulation)
- If fertilisation does not occur, menstruation takes place
Sex Determination
- Sex of a baby is determined by chromosomes.
- Females have XX chromosomes.
- Males have XY chromosomes.
- The father determines the sex of the child.
Role of Hormones Other Than Sex Hormones
Hormones also influence:
- Growth
- Mental development
- Emotional behaviour
Importance of Balanced Diet
A balanced diet during adolescence should include:
- Proteins
- Carbohydrates
- Fats
- Vitamins
- Minerals (especially calcium and iron)
Proper diet ensures healthy growth and development.
Personal Hygiene
Maintaining personal hygiene is important during adolescence to:
- Prevent infections
- Avoid skin problems
- Maintain overall health
Physical Exercise
Regular exercise helps in:
- Proper growth
- Strong bones and muscles
- Maintaining mental well-being
Important One-Word Answers for Exams
- Period between childhood and adulthood – Adolescence
- Age at which adolescence begins – 11
- Age at which adolescence ends – 19
- Sudden increase in height – Growth
- Stage when body changes begin – Puberty
- Hormones released by testes – Testosterone
- Hormones released by ovaries – Oestrogen
- Male reproductive hormone – Testosterone
- Female reproductive hormone – Oestrogen
- Glands that secrete hormones – Endocrine
- Master gland of the body – Pituitary
- Hormone controlling growth – Growth hormone
- Gland controlling metabolism – Thyroid
- Hormone secreted by thyroid – Thyroxine
- Iodine deficiency disease – Goitre
- Gland producing insulin – Pancreas
- Hormone controlling blood sugar – Insulin
- Glands located above kidneys – Adrenal
- Hormone for stress and emergencies – Adrenaline
- Voice box – Larynx
- Adam’s apple visible in boys – Larynx
- Development of breasts in girls – Puberty
- Hair growth under arms and pubic region – Puberty
- Monthly release of ovum – Ovulation
- First menstrual flow – Menarche
- End of menstrual cycle – Menopause
- Cycle of changes in female body – Menstrual cycle
- Ability to reproduce – Maturity
- Increase in muscle mass in boys – Testosterone
- Sex-determining chromosomes – X and Y
- Chromosome determining female child – X
- Chromosome determining male child – Y
- Balanced intake of nutrients – Diet
- Diseases spread due to lack of hygiene – Infections
- Period of rapid physical changes – Adolescence