1. What is the term used for chemical secretions of endocrine glands responsible for changes taking place in the body?
Ans:
The chemical substances secreted by the endocrine glands are called hormones. Hormones regulate and control various changes and functions in the body.
2. Define adolescence.
Ans:
Adolescence is the transitional period between puberty and adulthood during which the body undergoes various physical, emotional, and hormonal changes, leading to reproductive maturity.
It typically begins around the age of 11 and lasts until 18 or 19 years. However, the duration of adolescence may vary from person to person.
3. What is menstruation? Explain.
Ans:
Menstruation is the regular monthly process in females where the uterine lining sheds if fertilisation does not occur. It is a part of the female reproductive cycle and begins at puberty.
Each month, the uterus prepares itself to receive a fertilised egg by forming a thick, blood-rich lining.
If the egg is not fertilised, the uterine lining breaks down and is discharged along with blood through the vagina.
This process lasts for 2 to 8 days and occurs every month in a cycle known as the menstrual cycle.
4. List changes in the body that take place at puberty.
Ans:
The changes that occur in the body during puberty include:
a) Increase in height and weight: The body experiences a rapid growth spurt.
b) Hair growth: Hair starts appearing in areas like the underarms, legs, hands, and face (especially in boys).
c) Reproductive organ development:
In females, ovaries enlarge and start producing mature eggs.
In males, the testes grow and begin producing sperms.
d) Body shape changes:
In males, shoulders broaden, and the chest widens.
In females, the region below the waist becomes wider.
e) Acne development: Excess secretion of oil by the skin glands causes acne.
f) Voice changes in boys: The larynx grows larger, and the vocal cords become longer and thicker, resulting in a hoarse voice (commonly referred to as the “Adam’s apple” becoming prominent).
5. Prepare a Table having two columns depicting the names of endocrine glands and hormones secreted by them.
6. What are sex hormones? Why are they named so? State their function.
Ans:
Sex hormones are chemical substances produced by sex organs that regulate the development of reproductive functions and secondary sexual characteristics in males and females.
They are called sex hormones because they are associated with reproduction and sexual development.
Functions of sex hormones:
Oestrogen (female sex hormone):
Responsible for the development of secondary sexual characteristics in females, such as:Enlargement of breasts
Development of the female reproductive system
Testosterone (male sex hormone):
Responsible for secondary sexual characteristics in males, such as:Growth of a beard and mustache
Development of male reproductive organs
Hoarseness of voice
7. Choose the correct option.
(a) Adolescents should be careful about what they eat because:
(ii) proper diet is needed for the rapid growth taking place in their body.
(ii) proper diet is needed for the rapid growth taking place in their body.
(b) Reproductive age in women starts when:
(i) menstruation starts.
(i) menstruation starts.
(c) The right meal for adolescents consists of:
(ii) chapati, dal, vegetables.
(ii) chapati, dal, vegetables.
8. Write notes on:
(a) Adam’s apple:
The Adam’s apple is a protruding part of the throat in males, which is formed due to the growth of the larynx during puberty.
In boys, sex hormones cause the larynx to grow larger, making the vocal cords longer and thicker. This results in a hoarse and deep voice.
In females, the larynx remains small and less visible, leading to a high-pitched voice.
(b) Secondary sexual characters:
Secondary sexual characteristics are the features that appear during puberty, helping to distinguish male and female bodies.
Characteristics in males:
Deepening of voice
Growth of a beard and mustache
Broadening of the chest
Growth of hair in the genital and underarm areas
Characteristics in females:
Beginning of the menstrual cycle
Growth of breastsGrowth of hair in the genital and underarm areas
(c) Sex determination in the unborn baby:
The sex of the unborn baby is determined by the type of sex chromosomes inherited from the parents.
Chromosomal basis of sex determination:Females have XX chromosomes in their cells.
Males have XY chromosomes in their cells.
The ovum (egg) always contains an X chromosome, while the sperm can carry either an X or a Y chromosome.
How it works:
If the sperm contributes an X chromosome, the baby will be a girl (XX).
If the sperm contributes a Y chromosome, the baby will be a boy (XY).
9.Word game :
Use the clues to work out the words.
Across
Protruding voice box in boys
Glands without ducts
Endocrine gland attached to brain
Secretion of endocrine glands
Pancreatic hormone
Female hormone
Down
Male hormone
Secretes thyroxine
Another term for teenage
Hormone reaches here through blood stream
Voice box
Term for changes at adolescence
Ans
Across
Adam’s apple
Endocrine
Pituitary
Hormone
Insulin
Estrogen
Down
Testosterone
Thyroid
Adolescence
Target site
Larynx
Puberty