Class8.L-9. Endocrine System and Adolescence






EXERICE

A.Choose the correct option for each of the following .

1.The hormone that is released under stress or excitement – c)Adrenaline .

2.The hormone secreted by pancreas – a)Insulin

3.The hormone responsible for the development of secondary sexual characters in males – c)Testosterone

4.The fusion of male and female gametes – c)Fertilization .

5.A secondary sexual character in females –  a)Enlarged breasts .

B.State whether the following statements are True (T) or False (F) .

1.The female gamete is motile . (F)

2.The release of an ovum from the ovaries is called ovulation. (T)

3.Males develop a deep voice during puberty . (T)

4.The menstrual cycle in females is not regulated by hormones . (F)

5.All parts of the human body grow at the same rate . (F)

C.Fill in the blanks with correct words .

1.The first menstrual flow that begins at puberty is known as- Menarche .

2.Oestrogen is the –female hormone.

3.The changes that occur during adolescence are regulated by- hormones .

4.The period between childhood and adulthood is referred to as –Adolescence .

5.The male sex hormone is called – testosterone .

D.Answer  the following question in one sentence each.

1.At what ages do girls and boys reach adolescence .
ANS:-Between the age of 11-16 years in boys and 10-15 in girls, they reach adolescence.

2.List two changes brought about by the release of adrenaline.
ANS:-When adrenaline hormone release it regulates – a)Heart beat
b)breathing rate  c)blood pressure .

3.Define adolescence and puberty .
ANS:-
Adolescence : The period of transition from childhood to adulthood is called adolescence .
Puberty :the time in the life of human beings when they become sexually mature is called puberty.

4.List two important reasons to maintain personal hygiene during puberty.
ANS:-Two important reasons to maintain personal hygiene during puberty are:
a) Clothes must be changed every day as unhygienic conditions may lead to bacterial or fungal infections.
b) Girls should maintain proper hygiene during menstruation and keep track of their menstrual cycle.

5.Differentiate between a gland and hormone .
ANS:-
Gland
Hormone
Glands  are some special structures located at specific places inside our body which secrete certain substance.
The chemical substances that the endocrine glands secrete are called hormones .


E.Answer the following questions briefly.

1.Name the two types of glands found in our body and state where they are situated .
ANS:- Two types of gland found in our body are :
a)Pituitary gland :- Situated at the base of the brain .
b)Thyroid gland : - Situated at the neck region .

2.Explain why people experienced mood swings during adolescence .
ANS:-People experienced mood swings during adolescence because of an increase in the hormonal levels .

3.What is the role of growth hormones ?
ANS:-Growth hormones regulates the growth of bones and muscles .Deficiency of this hormone can cause dwarfism wherein an individual stops growing early and shows no further growth at all .

4.What is the role of the testes and ovaries in the human body .
ANS:-
Ovaries:- The ovaries are the egg producing female reproductive organs .They also secrete the oestrogen and progesterone hormones which are involved in appearance of secondary sexual characters and change take during menstrual cycle.
Testes:-Testes are the endocrine glands that secrete testosterone hormone which is responsible for appearance of the secondary sexual characters in male’s body.

5.What is menstruation and when does it occur ?
ANS:-In females , the phenomenon by which  the released egg and the thickened lining of the uterus along with its blood vessels are shed from the body, is known as  menstruation .
When fertilization does not occur, menstruation take place.

F.Answer the following questions in detail.

1.Write a short note on any three endocrine glands .Also ,state where they are located in the body and hormone that they release. Write about the effects of the hormones they secrete .
ANS:- About any three endocrine glands are discussing below:

a)Pituitary gland : It is a pea-sized gland situated at the base of the brain. It regulates the functioning of most of the other endocrine glands. The pituitary gland in turn regulated by a structure called hypothalamus present in the brain. This gland secreted a growth hormone which regulate the growth of muscles and bones .It also secrete some other hormone like – TSH,FSH,LH etc.

b)Thyroid hormone : The thyroid gland is located in the neck region and secretes a hormone called thyroxine . Iodine is necessary for the secretion of thyroxine .This hormone regulates the rate of metabolism , physical growth and mental development of an individual .The deficiency of this hormone causes simple goitre.

c)Adrenal gland : The adrenal glands are triangular in shape and situated on top of the two kidneys. They secrete a hormone called adrenaline .This hormone is secreted when the body faces situations of excitement, fear or stress .It regulates the heartbeat, breathing rate and blood pressure which prepares the body for action .

2.Explain the role of hormones during the puberty ?
ANS:- During puberty different hormones plays an important role in male and female body.  Some of them are as follows:
a)Growth hormone : This hormone secreted by  pituitary gland which regulates the  growth of bones and muscles.

b)Stimulating hormone: Stimulating hormones such as follicle-SH and Luteinizing-H stimulate the gonads to release their respective hormones and Thyroid-SH regulates the secretion of hormone of Thyroid gland.

c)Thyroxine hormone: This hormone secreted by thyroid gland which regulates the rate of metabolism, physical growth and mental development of an individual.

d)Adrenaline hormone: This hormone is secreted by adrenal gland during excitement ,fear , stress to regulate heart beat , breathing rate , blood pressure .

e)Oestrogen/Progesterone hormone: Oestrogen hormone responsible for appearance of the secondary sexual character in females , while progesterone hormone is involved during menstrual cycle.

d)Testosterone : This hormone is responsible for the appearance of the secondary sexual character in males .

3.List any five consequences of drug abuse .
ANS:- Five consequences of drug abuse are :

a)EDUCATION:-Drug abusing students may develop attentive and behavioral difficulties , irregular in classes  or  they may drop out of school.

b)WORK PLACE:-Addiction can lead to lack of concentration, inability to work, accidents ,job turnover  etc.

c)FAMILY:- Drug abuse can leads addicts to lack of participation in family activities, lake of emotional commitment  and support for parents and children .As a result addicts abandon their family and friends.

d)CRIME:-Drug addicts may steal to pay for their drugs out of desperation,
unaware of the wrong that they are committing.

e)HIV/AIDS:-Addicts who share needles to inject the drug into their body face the danger of getting infected with the HIV, which can cause the AIDS. AIDS is a fatal disease that has no cure so far.

4)List five dietary requirements and practices for adolescent to stay healthy .
ANS:-
a) Food rich in calories and protein must be consumed. Examples of calorie-rich foods include grains , nuts, pulses, meat, milk and milk products, fruits and vegetables. Such foods meet the growing demands of the body.

b)Calcium and iron-rich foods like milk, leafy vegetables and meat help to increase bone density and prevent anaemia.

c)Having meals at the right time is also very important; skipping meals must be avoided.

d)Food consumption has to be balanced with the amount of physical activity like walking, jogging,  cycling , playing different outdoor games etc which keeps the body fit and healthy .

e)During ,adolescence , there is excess secretion of sweat and bodily fluid , which leads to  body odour. Hence it is important to bath daily and keep the body clean .

5.What are secondary sexual characters ? Explain. Also, list the factors that bring about these changes .
ANS:-  Secondary sexual characters are as follows :

a)Increase in height: This may happen gradually or sometimes a sudden change in height can take place due to the elongation of the bones in the arms and legs.



b)Activity of sweat and oil glands: Sweat glands responsible for body odour  and oil glands responsible for acne and pimples on the face.

c)Development of body hair: In both boys and girls, hairs develop under armpits and in the pubic region; boys also develop hair on the face and chest.

d)Voice changes: In males, the larynx increases in size and appears as a protrusion in the throat. During this stage, the voice cracks and the individual develops a deep voice. Females may develop a high-pitched and shrill voice.

e)Body changes: In males, the shoulders become broader and the chest becomes wider due to increased muscle development. In females, the waist broadens and deposition of fat around the hips takes place.




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