Haryana State Board HBSE 8th Class Science Solutions Chapter 10 Reaching the Age of Adolescence Textbook Exercise Questions and Answers.
Haryana Board 8th Class Science Solutions Chapter 10 Reaching the Age of Adolescence
HBSE 8th Class Science Reaching the Age of Adolescence Textbook Questions and Answers
Question 1.
What is the term used for secretions of endocrine glands responsible for changes taking place in the body?
Answer:
Hormones.
Question 2.
Define adolescence.
Answer:
Adolescence: The period of life, when the body undergoes changes, leading to reproductive maturity is called adolescence.
Question 3.
What is menstruation? Explain.
Answer:
When egg produced by ovary does not get fertilized, it along with the thickened lining of the uterus and blood vessels get flown off out of the body every month as bleeding in women. This is called menstruation.
Question 4.
List the changes in the body that take place at puberty.
Answer:
Certain changes take place in the bodies of boys and girls at age of puberty. These include:
(i) Growing of hair at different body parts
(ii) Sudden increase in height.
(iii) Growth of moustaches and beards in boys.
(iv) Voice,of boys get coarsed.
(v) Development of breast in girls and hips get heavy.
(vi) Development of sex organs.
Question 5.
Prepare a table having two columns depicting names of endocrine glands and hormones secreted by them.
Answer:
| Endocrine Organs | Hormones secreted |
| (i) Thyroid | (i) Thyroxine |
| (ii) Pancreas | (ii) Insulin |
| (iii) Adrenal glands | (iii) Adrenalin |
| (iv) Pituitary gland | (iv) Growth hormones |
| (v) Testes | (v) Testosterone |
| (vi) ovaries | (vi) Estrogen |
Question 6.
What are sex hormones? Why are they named so? State their function.
Answer:
Hormones which constitute the secondary sexual characters are called sex hormones. They are called sex hormones because it is because of them that sex is diferentiated i.e. a boy is distinguished from a girl due to these hormones. Their function is to develop the secondary sexual characters in boys and girls.
Question 7.
Choose the correct option:
(a) Adolescents should be careful about what they eat, because ………….
(i) proper diet develops their brains.
(ii) proper diet is needed for the rapid growth taking place in their body.
(iii) adolescents feel hungry all the time.
(iv) taste buds are well developed in teenagers.
Answer:
(ii) proper diet is needed for the rapid growth taking place in their body.
(b) Reproductive age in women starts when their …………..
(i) menstruation starts.
(ii) breasts start developing.
(iii) body weight increases.
(iv) height increases.
Answer:
(i) menstruation starts.
(c) The right meal for adolescents consists of …………
(i) chips, noodles, coke.
(ii) chapati, dal, vegetables.
(iii) rice, noodles and burger.
(iv) vegetable cutlets, chips and lemon drink.
Answer:
(ii) chapati, dal, vegetables.
Question 8.
Write notes on:
(a) Adam’s apple.
(b) Secondary sexual characters.
(c) Sex determination in the unborn baby.
Answer:
(a) Adam’s Apple:
Adam’s apple is a protruding part in the throat. It is the enlarged voice box or larynx, which gets enlarged at the onset of puberty. This makes the voice of the boys hoarse.
(b) Secondary Sexual Characters are the characters which distinguish a boy from a girl. Characters like hair on chest, under the arms, development of breast, beard and moustaches etc. are all called secondary sexual characters.
(c) Sex determination in unborn baby: The sex of the unborn baby is determined by the sex chromosomes of the father. An unfertilized
egg always have X chromosome. If a sperm contributes X chromosome then the baby will be a female and if the sperm contributes Y chromosome, the baby will be a male. So it is the father, who is responsible for the sex of the unbomhaby.
Question 9.
Word game: Use the clues to work out the words.
Across
3. Protruding voice box in boys
4. Glands without ducts
7. Endocrine gland attached to brain
8. Secretion of endocrine glands
9. Pancreatic hormone 10. Female hormone
Down
1. Male hormone
2. Secretes thyroxine
3. Another term for Teenage
5. Hormone reaches here through blood stream
6. Voice box
7. Term for changes at adolescence
Answer:
Question 10.
The table below shows the data on likely heights of boys and girls as they grow in age. Draw graphs height and age for both boys and girls on the same graph paper. What conclusions can be drawn from these graphs?
| Age Year | Height (cm) | |
| 0 | Boys | Girls |
| 4 | 53 | 53 |
| 8 | 96 | 92 |
| 12 | 114 | 110 |
| 16 | 129 | 133 |
| 20 | 150 | 150 |
Answer:
We conclude that girl are taller than boys age of 12 yr. generally and there height is same at the age of 16 years but some boys gain height and generally become taller then girls.
Extended Learning – Activities And Projects
1. Find out from your elder relatives about their awareness of the leagal status of early marriage. You yourself may get information on it from your teacher, parents, a doctor or the internet. Write a two-minute speech explaining why early marriage is not good for the couple.
Answer:
The legal marriagable age for girls is 18 years and for boys it is 21 years. Before this age marriage is considered a crime. Early marriage is not good for couples because they are not prepared physically and mentally for the responsibilities of married life. A girl attains sexual maturity at age of about eighteen years. Before that her resproductive system is not fully prepared to bear a baby. Similarly boys are not capable of running the household as most of the boys at this age are pursuing their studies. So, the boys and girls should attain physical and mental maturity before getting married.
2. Collect newspaper cuttings and information in magazines about HIV/AIDS. Write a one page article of 15 to 20 sentences on HIV/AIDS.
Answer:
HIV/AIDS is a sexually transmitted diseased (STD) that means this diseases mostly spreads by sexual contacts with an HIV/AIDS infected persons. AIDS stands for Acquired Immunodeficiency Syndrome. It is created by HIV virus. This disease is a fatal disease for which no permanent treatement has been deviced by the scientists. AIDS is actually a disease which destroys the patients immune system slowly. The damage is most of the time permanent and beyond repair. Due to weak immunity the patient easily fall prey to many diseases which eventually kill the person.
Prevention is the only cure for HIV/AIDS. It is advised that one should maintain sexual hygiene and practice safe sexual relationship with a single partner.
3. In our country, according to a census, there are 882 adolescent femals for every 1000 males. Find out:
(a) the concerns of the community regarding this low ratio. Remember that the chance of having a boy or a girl is equal.
(b) what amniocentesis is and how useful this technique is. Why, is its use for indentification of sex of the unborn child banned in India l
Answer:
(a) The society is quite concerned about this issue. This is going to create a problem for them in future as it will become difficult for the boys to find girls for marriage.
(b) It is used to see, if all the organs of a feotus are developing well. It is banned in India to use this technique to determine the sex of the unborn child because they kill the female feotus to have baby boys in future. This is called female feoticide. The female feoticide has disturbed the ratio of boys and girls in India.
4. Put your ideas together and write a short note on the importance of knowing facts about reproduction.
For more information , visit:
- www.teenshealth.org/teen/sexual_health/
- www.ama_assn.org/ama/pub/category/ 1947.html
- www.adolescenthealth.com
Answer:
It is important to know facts about reproduction, because this phase i.e. reproduction phase has to come in every bodies life. It will help to handle all the physical and mental changes coming with sexual maturity in the bodies. It will also help in deciding one’s own course of life in future and save for many STDs.
HBSE 8th Class Science Reaching the Age of Adolescence Important Questions and Answers
Very Short Answer Type Questions
Question 1.
What is the phase of life when the body undergoes changes to attain reproductive maturity called?
Answer:
Adolescence.
Question 2.
What is the age period of adolescence?
Answer:
13 years to 18 years.
Question 3.
What is reproductive maturity called?
Answer:
Puberty.
Question 4.
Write any two changes in bodies of boys during adolescence.
Answer:
Increase in height, hairy line above lips.
Question 5.
What makes a person tall during adolescence?
Answer:
Elongated long bones of arms and legs.
Question 6.
What happens to voice box at puberty?
Answer:
It begins to grow.
Question 7.
What is the protruding part of the larynx visible in boy’s throat called?
Answer:
Adam’s Apple.
Question 8.
What changes occur in the voice of boy’s at the onset of puberty?
Answer:
It becomes hoarse.
Question 9.
Why do growing boys and girls get acnes or pimples?
Answer:
Due to increased secretions of sebacious glands.
Question 10.
What are those characters called, which distinguish a boy from a girl?
Answer:
Secondary sexual characters.
Question 11.
Give any one secondary sexual character of boys.
Answer:
Growth of moustaches and beard.
Question 12.
Give any one secondary sexual character of girls.
Answer:
Growth of breasts.
Question 13.
What controls the body changes during adolescence?
Answer:
Hormones.
Question 14.
What are hormones?
Answer:
Hormones are the chemical substances secreted by Endocrine glands.
Question 15.
Name the hormones secreted by testes.
Answer:
Testosterone.
Question 16.
Which hormone is secreted by ovaries 7
Answer:
Estrogen.
Question 17.
Which endocrine gland is called the master gland?
Answer:
Pituitary gland.
Question 18.
What are hormones secreted by testes and ovaries called collectively?
Answer:
Sex hormones.
Question 19.
Name the sex hormones secreted by testes and ovaries.
Answer:
Testosterone and Estrogen.
Question 20.
Name any one hormone secreted by Pituitary gland.
Answer:
Follicle stimulating Hormone or FSH.
Question 21.
Which hormone is responsible for the maturity of ova or sperms?
Answer:
Follicle stimulating hormone.
Question 22.
What is the common name given to ova and sperms?
Answer:
Gametes.
Question 23.
What is the beginning of menstruation called?
Answer:
Menarche.
Question 24.
What is the stoppage of menstruation called?
Answer:
Menopause.
Question 25.
What are the names given to sex chromosomes?
Answer:
X and Y.
Question 26.
Which sex chromosome determines the sex of body?
Answer:
Y Chromosome.
Question 27.
Which hormone is secreted by thyroid?
Answer:
Thyroxin.
Question 28.
Which hormone is secreted by pancreas?
Answer:
Insulin.
Question 29.
Which hormone controls the blood sugar level?
Answer:
Insulin.
Question 30.
Which hormone is secreted by Adrenal glands?
Answer:
Adrenalin.
Question 31.
Which hormone is called stress hormone?
Answer:
Adrenalin.
Question 32.
Why adrenalin is called stress hormone?
Answer:
Adrenalin is called stress hormone because it helps to calm down when one is angry.
Question 33.
What is a balanced diet?
Answer:
Diet containing all the necessary minerals in right proportion is called a balanced diet.
Question 34.
Name any food, which is called a balanced food in itself.
Answer:
Milk.
Question 35.
Which virus causes AIDS?
Answer:
HIV.
Short Answer Type Questions
Question 1.
What is adolescence?
Answer:
The phase of a person’s life, when his body undergoes changes to attain reproductive maturity is called adolescence. Adolescence begins at the age of 13 and lasts till the age of 18 or 19 years.
Question 2.
What are the signs of adolescence?
Answer:
Certain body changes mark the onset of puberty. Hairy line above lips in boys and sudden increase in height are the signs of puberty. In girls developing breasts show the on set of puberty.
Question 3.
Why some boys or girls have improportionate body parts during adolescence 7
Answer:
Some times the boys and girls have improportionate body parts. They look tall but face look smaller or other tilings. This is because all body parts do not grow at the same rate. But slowly they all catch up and body becomes balanced.
Question 4.
What changes take place in the body of adolescents during this period?
Answer:
Many changes take place in the bodies of boys and girls during adolescence. Their shoulders become wider and chest becomes broader. Girls get developed breasts and their hips become wider. Muscles of boys grow more than the girls.
Question 5.
What changes occur in the voice of boys and girls during puberty?
Answer:
The voice box or the larynx begins to grow. Boys have more grown voice box. It can be seen as the protrubed part in their throat.
Their voice becomes deep and sometimes, it grows more than controlled limit and their voice become hoarse. Girls get a high pitched voice.
Question 6.
What causes the changes in human body during puberty?
Answer:
The changes which occur during puberty are caused due to some chemical substances secreted by glands. These chemical substances are acalled Hormones. Endocrine system in human body has various glands, which secrete many important hormones which help the body to grow and mature.
Question 7.
How do sex hormones work in human body?
Answer:
In males the testosterone is secreted by testes and it causes growth of moustaches and beard. In girls estrogefi causes the development of mammary glands . They develop inside the breast and cause enlargement of breasts.
Question 8.
How does pituitary gland initiate the puberty in humans?
Answer:
Pituitary gland is called the master gland. It stimulates the testes and ovaries to produce sex hormones i.e. Testosterone and estrogen. These sex hormones further initiate the changes in body to attain sexual maturity.
Question 9.
What is menstruation?
Answer:
Monthly bleeding in women is called menstruation, when egg is matured and released by ovaries. It if not fertilized is dispelled by body along with the thick lining of uterus and with blood vessels. It is released from the body in form of monthly bleeding. It is called menstruation.
Question 10.
How the sex of the body is determined?
Answer:
Every human beings have 23 pairs of chromosomes in the nuclei of their cells. A pair of sex hormones are also among them. Females have XX sex chromosomes and males have XY sex chromosomes, when after fertilization the zygote get both X chromosomes from male and female, it will develop into a baby girl. When the zygote get X chromosome from female and Y from male, then it develops into a male. Thus the chromosome from a male decides if a baby will be a male or a female.
Long Answer Type Questions
Question 1.
What changes occur in body during puberty?
Answer:
Various changes occur in the body of human beings during puberty. These changes occur due to hormones secreted by reproductive organs. These changes are the following:
(a) Physical changes:
Various changes occur in the bodies of boys and girls. Boys get broader shoulders and wider chest. Sudden increase in their height is accompanied by growth of hair on their body parts. They get moustaches and beard.Girls get developed breasts and wider hips. More secretions from sweat and oil glands cause pimples and acnes in some young people.
(b) Change in Voice:
Voice of boys become deep due to enlarged larynx. Some time more growth in voice box is visible as Adam’s Apple in their throats. Their voice becomes even coarse in case of extra growth of larynx. Voice of girls become high pitched.
(c) Development of Sex Organs:
The reproductive organs of boys and girls become active. Testes start producing sperms and ovaries release matured eggs. Mental and Emotional Maturity: Young people become more mature mentally, emotionally and intellectually.
Question 2.
How are the changes of adolesence controlled by hormones?
Answer:
The endocrine system of body secretes many chemical substances which are directly poured into the blood stream, these chemical substances are called hormones. All changes taking place during adolescence are controlled by these hormones.
Pituitary glands secrete growth hormones which stimulates the sex organs to release hormones.. Testes start secreting testosterone and ovaries start secreting estrogen. These sex hormones cause secondary sexual characters. Estrogen causes development of mammary glands which develop under breast, thus breast starts enlarging in females.
Question 3.
How can bad habits like Drug addiction harm the young people?
Answer:
Boys and girls feel a little bit insecure and confused during adolescence due to sudden changes in their bodies. This can mislead them to certain unhealthy and immoral habbits, like drug addiction and many others. Drug addiction is a very bad habit which can spoil our lives. It is easy to start, taking drugs but very difficult to shun this habit. Drugs can cause many long term harms on our bodies.
They make our body weak and prone to many communicable diseases like AIDS and many other sexual disorders. AIDS virus HIV can pass on to a healthy person from an infected person by sharing the infected syringe. The drug addicts inject drugs by using syringe. The same syringe is shared by other addicts also, so the infected syringe can spread AIDS to others also.
Question 4.
Who is responsible to determine the sex of unborn baby: Father or mother?
Answer:
Each human being have 23 pairs of chromosomes in the nuclei of every cell. These chromosomes contain the hereditary information. Out of these chromosomes a pair of chromosome are called sex chromosomes, which are named X and Y Chromosomes. Each female has 2 X chromosomes while the males have one X chromosome and one Y chromosome. The unfertilized egg released by ovaries always have one X chromosome. Testes produce some sperms with X chromosome and some with Y chromosome.
If sperms with X chromosome fertilize with egg with unborn is a female, but if the sperms with Y chromosome fertilizes with egg, then the unborn baby will be a male. So, it becomes clear that it is the sperm released by father carrying X or Y chromosomes, that determines the sex of the unborn baby.
Question 5.
What should be done to maintain reproductive health?
Answer:
Following measures can help the young people to maintain their reproductive health.
(i) Balanced Diet:
Diet is very important for a growing body. Diet should be a balanced diet. Balanced diet contains all the necessary elements in required proportion. Elements like carbohydrates, proteins, fats and vitamins should be integral part of a balanced diet. Milk provides all the required elements in required proportion. Junk and fast food are good to taste but they are not nutritious so they should not be included in diet.
(b) Personal Hygiene:
One should keep one’s body clean by bathing everyday. All parts of the body should be washed properly because infections can take place due to more sweat and oil secretion by sweat and oil glands.
(c) Physical Exercise:
Daily routine of physical exercise can keep body fit and circulation of blood gets maintained providing energy to all parts of the body.
Reaching the Age of Adolescence Class 8 HBSE Notes
1. A baby becomes adult after passing a few development stages.
2. The age at which a child becomes capable of reproduction is called adolescence.
3. At the age of 11 years to 19 years a child reaches puberty.
4. Reproductive organs start developing as the puberty sets in.
5. Various changes occur in the bodies of boys and girls at age of puberty. Hair starts growing at different parts of body. Girls have developed breasts, heavy hips, boys get.moustaches and beard, their voice become heavy.
6. Height gain is prominent at age of puberty along with other changes. Hormones starts taking control of the reproductive organs, and make the beginning of maturity of reproductive organs.
7. Hormones are the chemical substances which are secreted by the pituitary glands directly into the blood stream.
8. Growth hormones stimulate other glands to secrete various other hormones to control various other body functions.
9. Various hormones secreted by different glands perform various functions. Ovaries and testes secrete hormones for sexual maturity, pancreas secrete Insulin to control sugar level, thyroid secret thyroxin and adrenal glands produce adrenalin. All these hormones are necessary for proper growth and development of body.
11. With onset of puberty females have hormones like estrogen. They have their uterine wall prepared to receive the fertilized egg. They have another phenomenon called menstruation. In this phenomenon they get the unfertilized egg flown out of body through blood.
12. Reproductive health needs a lot of care and one needs to maintain hygiene and physical activity.
13. Proper nutrition and balanced diet in necessary for growing body, so it should be taken care of.