Chapter 15 : Reaching the Age of Adolescence
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1. Endocrine glands release ________ into the blood
stream.
ANS: hormones
2. ________ is also known as the voice box.
ANS: larynx
3. Acne and pimples are common in adolescence due to
increased production of ________ by the ________ glands.
ANS: sebum,
sebaceous
4. Deficiency of ________ reduces the absorption of
calcium by the body.
ANS: Vitamin D
5. ________ hormone is essential for metamorphosis to
happen in a frog.
ANS: Thyroxine
6. ________ are chromosomes other than the sex
chromosomes.
ANS: Autosomes
1.
Ovary — (e) progesterone
2.
Pancreas — (d)
insulin
3.
Adrenals — (a)
adrenaline
4.
Testes — (b) testosterone
5.
Thyroid — (c) thyroxine
1. The period of life, marked by rapid changes leading
towards sexual maturity, is known as—
•
childhood
•
puberty
•
old age
•
adulthood
ANS: puberty
2. The onset of menstruation, in a human female, is
known as—
•
menarche
•
ovulation
•
menopause
•
adolescence
ANS: menarche
3. The hormone, which controls the body’s response to stress, is known as—
•
insulin
•
thyroxine
•
estrogen
•
adrenaline
ANS:
adrenaline
4. Out of following, the one that does not produce
hormones, is the—
•
thyroid gland
•
sebaceous
glands
•
pineal gland
•
testes
ANS: sebaceous glands
5. The mineral, whose presence is essential for a
tadpole to grow into a frog, is—
•
calcium
•
chlorine
•
selenium
•
iodine
ANS: iodine
1. State the meaning of the term ‘Adolescence’.
ANS:
Adolescence is the transitional stage between
childhood and adulthood marked by rapid physical and mental development.
2. Define puberty. State the various factors which
influence it.
ANS:
Puberty is the period during which an individual
attains sexual maturity and becomes capable of reproduction.
The factors influencing puberty are:
(a) heredity
(b) diet
(c) exercise
(d) environmental factors
3. Why are endocrine glands known as ductless glands?
ANS:
Endocrine glands are known as ductless glands because
they do not have ducts and pour their secretions directly into the bloodstream.
4. Why do tadpoles growing in iodine deficient waters
fail to grow into frogs?
ANS:
Iodine is necessary for the production of thyroxine
hormone, which is essential for metamorphosis in frogs. Therefore, tadpoles
growing in iodine deficient water fail to develop into frogs.
5. How does the pituitary gland control the maturation
of the gonads?
ANS:
The pituitary gland secretes hormones that stimulate
the testes and ovaries to produce sex hormones. These hormones help in the
maturation of the gonads.
6. Women, above the age of fifty, are (generally)
unable to give birth to children. Explain the reason for the same.
ANS:
Around the age of 45–50 years, menstruation stops
permanently in women. This stage is called menopause. After menopause, the
ovaries stop releasing ova and therefore women are generally unable to give
birth to children.
1. Enlist the changes which occur in males and females
during puberty.
ANS:
The changes occurring during puberty are:
(a) Increase in height.
(b) Change in body shape.
(c) Change in voice.
(d) Increased activity of sweat and sebaceous glands.
(e) Development of reproductive organs.
(f) Development of secondary sexual characters.
2. Arun and his sister Arunima are both teenagers.
Arunima observes a swelling on her neck, following which she visits a doctor.
The doctor identifies it to be a deficiency disease and prescribes medicines
along with suggesting dietary modifications. A few months later, Arun observes
a small protrusion on his throat and visits a doctor. However, the doctor
assures him that it is a normal feature in boys of his age.
(a) Identify the disease Arunima was suffering from
along with its cause.
ANS:
Arunima was suffering from goitre caused by deficiency
of iodine in the diet.
(b) Why do you think that no medication was prescribed
for Arun?
ANS:
No medication was prescribed for Arun because the
protrusion in his throat was Adam’s apple, which
is a normal feature appearing in boys during puberty due to enlargement of the
larynx.
3. Discuss how the sex of the unborn child gets
determined in human beings.
ANS:
In human beings, females have XX sex chromosomes while
males have XY sex chromosomes. The ovum always carries an X chromosome, whereas
the sperm may carry either X or Y chromosome.
(a) If an X-bearing sperm fertilises the ovum, the
zygote will have XX chromosomes and a girl child will be born.
(b) If a Y-bearing sperm fertilises the ovum, the
zygote will have XY chromosomes and a boy child will be born.
Thus, the sex of the child is determined by the
father.
4. Enlist the events that regularly occur in the
female reproductive system, after the onset of puberty, until menopause.
ANS:
The following events occur regularly in the female
reproductive system after puberty:
(a) One ovum matures in the ovary approximately every
28 days.
(b) The ovum is released into the oviduct.
(c) The lining of the uterus thickens to receive a
fertilised egg.
(d) If fertilisation occurs, the zygote develops in
the uterus.
(e) If fertilisation does not occur, the thickened
lining of the uterus breaks down and is shed off as menstruation.
5. Highlight the importance of exercise and good
personal hygiene during adolescence.
ANS:
Exercise during adolescence helps in proper growth and
development of the body, keeps the body fit, improves blood circulation and
reduces stress.
Good personal hygiene helps in preventing infections and maintaining good health. Regular bathing, clean clothes, proper dental care and cleanliness during menstruation are important during adolescence.
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