Reaching the Age of Adolescence Class 8 Worksheet Science Chapter 7

Q1: Which gland secretes insulin hormone? 

Ans: The pancreas secretes insulin hormone.

PancreasQ2: What element is needed for thyroxine production? 

Ans: Thyroxine production requires the presence of iodine.

IodineQ3: Name the endocrine gland attached to the brain. 

Ans: The pituitary gland is an endocrine gland attached to the brain.

Pituitary GlandQ4: What is a naturally balanced food for infants? 

Ans: For infants, mother’s milk provides all the nourishment that they need.

Q5: Why is an iron mineral important for our body? Write some iron-rich foods. 

Ans: The iron mineral is important for our body because it builds blood. Iron-rich food includes leafy vegetables, jaggery, meat, citrus, Indian gooseberry (amla), etc.

Q6: Why is exercise important during adolescence? 

Ans: Walking and playing in fresh air keeps the body fit and healthy. Thus, all young boys and girls should take walks, exercise, and play outdoor games.

Q7: What is the function of the adrenalin hormone in the body? 

Ans: Adrenals also produce the hormone adrenalin. It helps the body to adjust to stress when one is very angry, embarrassed, or worried.

Q8: What is the most conspicuous change during puberty? 

Ans: The most conspicuous change during puberty is the sudden increase in height.

Q9: Define adolescence. 

Ans: The period of life, when the body undergoes changes, leading to reproductive maturity, is called adolescence. Adolescence begins around the age of 11 and lasts up to 18 or 19 years of age. In girls, adolescence may begin a year or two earlier than in boys. Also, the period of adolescence varies from person to person.

Q10:  Why early marriage and motherhood is harmful to girls? 

Ans: Early marriage and motherhood cause health problems in the mother and the child. It also curtails employment opportunities for the young woman and may cause mental agony as she is not ready for the responsibilities of motherhood.

Q11: Why do young people get acne? 

Ans: During puberty, the secretion of sweat glands and sebaceous glands (oil glands) increases. Many young people get acne and pimples on the face at this time because of the increased activity of these glands in the skin.

Q12: What is the effect of a larger voice box on grown-up boys? 

Ans: The bigger voice box for boys gives a deeper voice or low-pitched voice to the boys. In adolescent boys, sometimes, the muscles of the growing voice box go out of control and the voice becomes hoarse.

Q13: What is menstruation? Explain.

Ans: 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 fertilization 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.

Q14: How does the height of boys and girls change during puberty? 

Ans: At the time of puberty the long bones, that is, the bones of the arms and the legs elongate and make a person tall. Initially, girls grow faster than boys but by about 18 years of age, both reach their maximum height. The rate of growth in height varies in different individuals. Some may grow suddenly at puberty and then slow down, while others may grow gradually.

Q15: What are sex hormones? Why are they named so? State their function.

Ans: Sex hormones are chemical substances produced by a sex gland or other organ. For example, the testes make the male sex hormone called testosterone and the ovaries make the female sex hormone called estrogen. These hormones affect the sexual features of an organism. Hence they are called sex hormones.

Functions
Testosterone – It produces male secondary sexual characteristics in boys such as deeper voice, growth of mustache and beard, broad shoulders and chest, adam’s apple, more muscles, development of reproductive organs, etc.
Estrogen – It produces female secondary sexual characteristics in girls such as the development of breasts, broader hips, development of reproductive organs, etc.