PETIT SEMINAIRE HIGHER SEC SCHOOL- PUDUCHERRY

VIII STD SCIENCE NOTES: LESSON-8 Reaching the age of Adolescence

A. Choose the correct option.
1. Which among these is not seen in males during puberty?
a. Growth of beard, moustache b. Increase in height c. Decrease in muscle mass d. Deeper voice
2. The growth hormone is secreted by
a. hypothalamus b. pituitary c. adrenal d. pancreas
3. Which of the following is a dual gland?
a.Adrenal b. Pituitary c. Pancreas d. Thyroid
4. Ovaries secrete
a.progesterone b. Oestrogen c. testosterone d. Both a and b
5. Which among these is a secondary sexual character in females?
a.Development of breasts b. Increase in weight c. Increase in height d. Increase in muscle mass
6. ___________is caused by the deficiency of thyroxine hormone.
a.Diabetes b. Simple goitre c. Exophthalmic goitre d. Grave's disease
B. State whether the following statements are true or false. Correct the false statements.
1. Testosterone and oestrogen are also known as sex hormones- True
2. Diabetes is caused due to the over-production of insulin- False
Correct statement: Diabetes is caused due to the under-production of insulin
3. The protruding organ called Adam's apple is seen in females- False
Correct statement: The protruding organ called Adam's apple is seen in Males.
4. Hormones are responsible for the development of secondary sexual characters in malesand females- True
5. Endocrine glands pour their secretions directly into the bloodstream-True
C. Answer the following questions in one word or a sentence.
1. What is Puberty?
Puberty is the time in life when the body becomes biologically capable of sexualreproduction.
2. Name the male and female sex hormones.
Male hormone : Testosterone
Female hormone : Oestrogen and Progesterone
3. What is menopause?
When the woman is between 45 and 50 years old, the menstrual cycle stops. Thisis called menopause.
4. Name two examples of Exocrine glands.
Sweat glands and salivary glands are exocrine glands.
5. Name the butterfly-shaped gland located in the neck region and the hormoneproduced by it.
The butterfly-shaped gland in the neck is the thyroid gland. It produces thyroxinehormone.
D. Answer the following questions in brief.
1. What is menstruation?
➢ If fertilization does not occur, the released egg and the thickened lining of the uterus along with its blood
vessels are shed from the body. This is called menstruation.
➢ The menstrual flow lasts for about 4 to 6 days.
➢ Menstruation occurs once in about 20 to 30 days.
2. What causes diabetes mellitus? Write its symptoms.
Diabetes mellitus is a chronic disease seen in people wherein the pancreas does not produce enough insulin
or the target sites stop responding to the insulin that is produced. Symptoms include frequent urination, lethargy,
excessive thirst and hunger.
3. Write any two ways through which adolescents can maintain their personal hygiene.
Two ways by which adolescents can maintain personal hygiene:
➢ The sweat and sebaceous glands are more active at this stage, which can lead to body odour. Taking a bath
regularly cleans the skin and prevents bacterial infections.
➢ Keeping genital areas clean also keeps the body fit.
4. Why should adolescent pregnancy be avoided?
➢ When a girl becomes pregnant, her life completely changes.
➢ She may not be able to continue her education and thus her job prospects reduce.
➢ She may be pushed to poverty and consequently, her health may suffer.
➢ Complications from pregnancy and childbirth are a leading cause of death among adolescent girls.
➢ Hence, adolescent pregnancy must be avoided.
5. Name the hormone produced by the pituitary gland. What are the diseases associated with over-secretion or
under-secretion of this hormone?
➢ Pituitary gland produces an important hormone called the Growth Hormone (GH).
➢ It is essential in children to maintain a healthy body and growth of bones and muscles. In adults, it aids
maintaining healthy bone and muscle mass.
➢ A deficiency of this hormone causes dwarfism, wherein the child stops growing in height.
➢ If the pituitary gland produces too much hormone, a child’s bones and body parts may grow abnormally fast
and can result in a condition called gigantism.
E. Answer the following questions in detail.
1. Describe the menstrual cycle.
➢ From the beginning of puberty, one ovum is released every 28 days.
➢ During this period, the uterus prepares itself to receive the egg.
➢ The inner lining of the uterus becomes thick and spongy and develops a lot of blood vessels.
➢ After ovulation, the egg travels to the fallopian tube.
➢ If fertilization occurs in the fallopian tube, it results in the formation of zygote, which gets implanted in the
wall of the uterus.
➢ If fertilization does not occur, the released egg and the thickened lining of the uterus along with its blood
vessels are shed from the body. This is called menstruation.
➢ The menstrual flow lasts for about 4 to 6 days.
➢ Menstruation occurs once in about 20 to 30 days.
➢ This entire set of events, which includes the production and release of the unfertilized egg by the ovaries
along with menstrual flow, is called the menstrual cycle.
2. How does eating a balanced diet help an adolescent?
An adolescent has increased nutrient needs and must eat a balanced diet to remain fit and stay healthy.
Both over-eating and under-eating can affect the health. Inadequate diet can lead to stunted growth.
The following tips can be helpful in ensuring good health.
➢ Foods including carbohydrates and proteins that are essential for growth must be consumed.
➢ Grains, nuts, pulses, meat, milk, cheese and eggs provide energy required for various physical activities.
➢ Vegetables and fruits are rich sources of vitamins and minerals.
➢ Calcium helps to build bones, iron helps in formation of blood and vitamin C boosts immunity.
➢ Milk is a complete food and must be consumed every day. It is rich in calcium, phosphorus and fats.
➢ Eating regular meals is important; skipping meals must be avoided.
➢ Eating packed, canned and junk food that have very less nutritional value must be avoided.
➢ Since girls start menstruating at this age, they must consume food rich in iron, calcium and zinc.
3. Why should adolescents say NO to alcohol, drugs and tobacco? What are the effects of consuming them? Drug
abuse is a very common problem among adolescents. It refers to excessive use of certain drugs and
substances such as paan (betel leaf), tobacco, alcohol, pain killers and mind-altering chemicals. We must
always say NO to drugs, alcohol and tobacco.
Some harmful effects are:
✓ Tobacco reduces lung capacity, causes wheezing and can cause lung cancer.
✓ It strains the heart and reduces life-span.
✓ Alcohol affects all the body organs including the brain.
✓ It slows down brain activity, muscle co-ordination, reflexes and speech.
✓ Too much of alcohol can even reduce breathing or heart rate.
✓ Taking drugs can be dangerous.
✓ It can create hallucinations (imagining surroundings and feeling sensations that are unreal).
✓ It makes a person addictive.
✓ Addiction to any one of these can lead to lack of concentration, inability to work and lack of judgment, and
has negative impact on family relationships and friends.
✓ It also makes the users impulsive and they may find it difficult to maintain emotional stability.
4. Write the function of
a. Thyroid gland
➢ It is a butterfly-shaped gland located in front of the windpipe.
➢ It secretes a hormone called thyroxine.
➢ The main role of thyroxine is to regulate the metabolism, which is the body’s ability to break down food
and convert it to energy.
➢ It is also responsible for physical growth and mental development.
➢ The thyroid gland absorbs iodine from blood and then secretes thyroxine.
 b. Pancreas
➢ It is a flattened gland that lies between the stomach and the spine and is connected to the duodenum.
➢ It is called a dual gland as it acts both as an exocrine and an endocrine gland. It produces pancreatic juice,
which helps to digest protein in the food.
➢ There are special cells in the pancreas that produce a hormone called insulin, which helps to control the
level of glucose in the blood.
c. Hypothalamus
Hypothalamus, which is also located close to pituitary, sends signals to pituitary, gland to stimulate or inhibit
the hormone production.
6. List the secondary sexual characters of both males and females.
Secondary sexual characters in a male:
✓ Growth of body hair (armpits and pubic area), facial hair (moustache and beard)
✓ Enlargement of larynx (Adam’s apple)
✓ Development of testis
Secondary sexual characters in a female:
✓ Development of mammy glands and breasts
✓ Growth of body hair (armpits and pubic area)
✓ Development of ovary