Endocrine System and Adolescence

Solutions for Biology, Class 8, ICSE

Assertion Reason Type Questions

5 questions

Question 2(a)

Assertion (A): The exocrine glands send their secretions (enzymes) to the target organs through ducts.

Reason (R): Such glands are called exocrine glands because their secretions act on the surface of organs.

  1. Both A and R are true.
  2. Both A and R are false.
  3. A is true and R is false.
  4. A is false and R is true.
Assertion Reason Type Questions

Answer:

Both A and R are true.

Explanation — Exocrine glands send their secretions (enzymes) to the target organs through ducts. These secretions usually act on the surface of organs, such as the skin or digestive tract.

Question 2(b)

Assertion (A): Endocrine glands pour their secretions directly into the blood in very large quantities.

Reason (R): Hormones are utilized in very large quantities continuously throughout the body as these secretions regulate the growth and development as well as many other metabolic activities of the body.

  1. Both A and R are true.
  2. Both A and R are false.
  3. A is true and R is false.
  4. A is false and R is true.
Assertion Reason Type Questions

Answer:

Both A and R are false.

Explanation — The endocrine glands have no ducts and they pour their secretions (hormones) directly into the blood. The secretions of these glands or hormones are secreted in very small quantities, and are carried to all parts of the body.

Question 2(c)

Assertion (A): Thyroxine is the hormone which regulates basal metabolism of the body and speeds up the rate of most activities of the body.

Reason (R): Its undersecretion is harmful which can cause different types of ailments but its oversecretion is very important as it increases the metobolic rate of the body.

  1. Both A and R are true.
  2. Both A and R are false.
  3. A is true and R is false.
  4. A is false and R is true.
Assertion Reason Type Questions

Answer:

A is true and R is false.

Explanation — Thyroxine is an iodine-containing hormone and is very important for our body. However, its oversecretion is harmful too as it can cause an increase in metabolic rate and heartbeat, weight loss, restlessness, and other issues.

Question 2(d)

Assertion (A): The hormone epinephrine is secreted by the Adrenal cortex when a person is under stress (physical or emotional), fearful or angry.

Reason (R): This hormone prepares the body to meet any emergency situation, i.e. to face the danger or flee from a situation.

  1. Both A and R are true.
  2. Both A and R are false.
  3. A is true and R is false.
  4. A is false and R is true.
Assertion Reason Type Questions

Answer:

A is false and R is true.

Explanation — Adrenal Medulla secretes adrenaline or epinephrine hormone, when a person is under severe stress (physical or emotional), fearful or angry. This hormone provides extra energy and strength to the body in any adverse (or emergency) situation.

Question 2(e)

Assertion (A): Oversecretion of insulin causes diabetes mellitus.

Reason (R): Insulin converts glycogen to glucose which increases blood sugar.

  1. Both A and R are true.
  2. Both A and R are false.
  3. A is true and R is false.
  4. A is false and R is true.
Assertion Reason Type Questions

Answer:

Both A and R are false.

Explanation — Insulin promotes the conversion of extra glucose to glycogen which is ultimately stored in the liver and muscles. Hence, insufficient secretion of insulin leads to an increase in the concentration of sugar (glucose) in the blood causing diabetes mellitus.

Long Answer Questions

10 questions

Question 1(a)

Distinguish between the following pair on the basis of the words indicated in the brackets.

Exocrine and Endocrine glands (secretion)

Long Answer Questions

Answer:

Difference between Exocrine and Endocrine glands on the basis of secretion:

CharacteristicExocrine glandsEndocrine glands
SecretionExocrine glands secrete their products like sweat, enzyme, mucus, sebum, saliva, milk, etc. into ducts.Endocrine glands secrete their products, known as hormones, directly into the bloodstream.

Question 1(b)

Distinguish between the following pair on the basis of the words indicated in the brackets.

Cretinism and Myxoedema (symptoms)

Long Answer Questions

Answer:

Difference between Cretinism and Myxoedema on the basis of symptoms:

CharacteristicCretinismMyxoedema
SymptomsCretinism occurs in infants resulting in physical and mental retardation.Myxoedema occurs in adults and is characterised by symptoms such as sluggishness with swelling on face and hands.

Question 1(c)

Distinguish between the following pair on the basis of the words indicated in the brackets.

Insulin and Glucagon (function)

Long Answer Questions

Answer:

Difference between Insulin and Glucagon on the basis of function:

CharacteristicInsulinGlucagon
FunctionInsulin lowers blood glucose levels by facilitating the uptake of glucose into cells and its conversion to glycogen in the liver and muscles.Glucagon raises blood glucose levels by promoting the conversion of glycogen back to glucose in the liver and muscles.

Question 1(d)

Distinguish between the following pair on the basis of the words indicated in the brackets.

Thyroxine and adrenaline (source)

Long Answer Questions

Answer:

Difference between Thyroxine and Adrenaline on the basis of source:

CharacteristicThyroxineAdrenaline
SourceThyroxine is produced by the thyroid gland.Adrenaline is produced by the adrenal glands.

Question 1(e)

Distinguish between the following pair on the basis of the words indicated in the brackets.

Human male and female hormone (one example of each)

Long Answer Questions

Answer:

Difference between Human male and female hormone on the basis of one example of each:

CharacteristicHuman male hormoneHuman female hormone
One exampleA common male hormone is testosterone.An example of a female hormone is estrogen.

Question 2(a)

Give reason/explain — Pituitary gland is considered as the "master gland".

Long Answer Questions

Answer:

Pituitary gland secretes some hormones that regulate the activity of other endocrine glands. So, the pituitary gland is also called the "master gland".

Question 2(b)

Give reason/explain — Epinephrine is also called as the 'emergency hormone'.

Long Answer Questions

Answer:

Epinephrine (also called adrenaline) is released by the adrenal glands in response to stress. This hormone prepares the body to meet any emergency situation i.e., to face the danger or flee from a situation. Hence it is called the 'fight or flight hormone' or the 'emergency hormone'.

Question 3

Draw neat and labelled diagrams of the thyroid gland showing its :

(a) Front view

(b) Back view

Long Answer Questions

Answer:

(a) Below labelled diagram shows the front view of the thyroid gland:

Draw neat and labelled diagrams of the thyroid gland showing its : (a) Front view (b) Back view. Endocrine System and Adolescence, Concise Biology Solutions ICSE Class 8.

(b) Below labelled diagram shows the back view of the thyroid gland:

Draw neat and labelled diagrams of the thyroid gland showing its : (a) Front view (b) Back view. Endocrine System and Adolescence, Concise Biology Solutions ICSE Class 8.

Question 4

Briefly write about the importance of physical hygiene during adolescence.

Long Answer Questions

Answer:

Physical hygiene plays a very important role in maintaining one's own health during adolescence. Following are some important practices for maintaining physical hygiene:

  1. Proper and safe food:
    1. To support rapid growth and development during adolescence, an adolescent should take a balanced diet including proteins, carbohydrates, fats, minerals, and vitamins. Milk, fruits and fresh vegetables should be part of the regular diet.
    2. Avoid stale food and excessive fast food.
    3. Perishable food items should be properly stored in refrigerator.
  2. Proper lifestyle:
    1. Avoid long hours of continuous table work.
    2. Avoid watching television and playing computer games for long hours.
    3. Avoid smoking and consumption of alcohol and drugs.
  3. Cleanliness:
    1. Washing hands with soap before and after meals, brushing teeth, taking regular bath, regular toilet habits should be followed.
    2. Clothes, especially undergarments should be changed daily. Wearing very tight clothes should be avoided.
    3. Eyes should be washed daily with clean and cold water. Rubbing of eyes with hands should be avoided to prevent entry of germs.
    4. Lack of cleanliness may lead to bacterial infection. Girls should take special care of cleanliness during the time of their menstrual cycle.
  4. Physical Exercise:
    1. All young boys and girls should walk, exercise and play outdoor games regularly.
    2. Physical activity is important to combat the stress and strain of adolescence.

Question 5

Briefly discuss any four activities which can be practiced to overcome stress.

Long Answer Questions

Answer:

Four activities which can be practiced to overcome stress are:

  1. Yoga — Yoga is a mind body practice that combines physical poses, controlled breathing and meditation or relaxation. It helps to reduce stress with:
    1. Increased flexibility.
    2. Increased muscle strength and tone.
    3. Improved respiration, energy and vitality.
    4. Weight reduction.
    5. Improved athletic performance.
  2. Exercise — Just 30 to 45 minutes of exercise at least three times a week can make one feel much healthier. Regular exercise can be done by running/jogging, swimming, cricket, football, hockey, etc.
  3. Proper sleep schedule — Sound and timely sleep helps one to reduce the level of stress.
  4. Reading — It is a great way to calm the mind and to gain knowledge.

Match The Following

1 question

Question 3

Match the items in Column A with those in Column B.

Column AColumn B
CretinismPituitary Gland
Diabetes MellitusAbnormal development of infant
Increased metabolic rateOversecretion of thyroxine
Simple goitreInsufficient iodine in food
Growth hormoneInsufficient insulin in blood
Match The Following

Answer:

Column AColumn B
CretinismAbnormal development of infant
Diabetes MellitusInsufficient insulin in blood
Increased metabolic rateOversecretion of thyroxine
Simple goitreInsufficient iodine in food
Growth hormonePituitary gland

Objective Type Questions

10 questions

Question 1(a)

Cortisone hormone is secreted by :

  1. Medulla of adrenal
  2. Cortex of adrenal
  3. Pancreas
  4. Thyroid
Objective Type Questions

Answer:

Cortex of adrenal

Reason — The adrenal cortex secretes Cortisone.

Question 1(b)

Which one of the following hormones stimulates the breakdown of glycogen in the liver into glucose?

  1. Insulin
  2. Adrenaline
  3. Glucagon
  4. Thyroxine
Objective Type Questions

Answer:

Glucagon

Reason — Glucagon stimulates the breakdown of glycogen in the liver to glucose.

Question 1(c)

Which one of the following hormones converts excess of glucose into glycogen

  1. Glucagon
  2. Thyroxine
  3. Insulin
  4. Adrenaline
Objective Type Questions

Answer:

Insulin

Reason — Insulin converts extra glucose to glycogen which is ultimately stored in the liver and muscles.

Question 1(d)

Which one of the following glands is also called the master gland :

  1. Pituitary gland
  2. Adrenal gland
  3. Thyroid gland
  4. Ovary
Objective Type Questions

Answer:

Pituitary gland

Reason — Pituitary gland regulates the activity of other endocrine glands. So, it is also called the "master gland".

Question 1(e)

The emergency hormone to face the danger or to fight is secreted by:

  1. Islets of Langerhans
  2. Adrenal cortex
  3. Pituitary
  4. Adrenal medulla
Objective Type Questions

Answer:

Adrenal medulla

Reason — Adrenaline hormone is also called the "fight or flight hormone". It is secreted by Adrenal medulla.

Question 1(f)

Which one of the following endocrine glands produces its hormone in large quantities as a result of emotional stimulation?

  1. Thyroid
  2. Islets of Langerhans
  3. Adrenal medulla
  4. Adrenal cortex
Objective Type Questions

Answer:

Adrenal medulla

Reason — Adrenal medulla secretes adrenaline (also called epinephrine or emergency hormone). This hormone is secreted when a person is under severe stress (physical or emotional).

Question 1(g)

In humans, increased thyroxine production results in:

  1. Increased metabolism
  2. Decreased metabolism
  3. Dwarfism
  4. Cretinism
Objective Type Questions

Answer:

Increased metabolism

Reason — Oversecretion of thyroxine causes an increased metabolic rate.

Question 1(h)

Akash is suffering from a disease caused due to insufficient secretion of thyroxine. It shows general sluggishness with swelling on the face and hands. This disease is caused due to the deficiency of :

  1. Iron
  2. Iodine
  3. Calcium
  4. Phosphorus
Objective Type Questions

Answer:

Iodine

Reason — Myxoedema is is a condition seen in an adult when insufficient amount of thyroxine is produced. It shows general sluggishness with swelling on the face and hands, caused due to the deficiency of Iodine.

Question 1(i)

Pituitary gland is considered as the 'master gland' of the body. Which of the following reasons supports this statement?

P. It is a pea-sized gland.

Q. It is the largest and strongest gland.

R. It regulates the activities of all other endocrine glands.

  1. Only P and R
  2. Only Q
  3. Only R
  4. Only P and Q
Objective Type Questions

Answer:

Only R

Reason — Pituitary gland is a pea-sized gland, located below the brain. However, it is called the 'master gland' due to the fact that it secretes several hormones, some of which regulate the activity of other endocrine glands.

Question 1(j)

Aman is in the state of mental or emotional strain which can be termed as 'stress'. In simple terms, people call it 'tension'. Which of the following ways can help Aman manage his stress?

P. Yoga and exercise.

Q. Uncontrolled eating and watching television.

R. Deep breathing and meditation

  1. Only P and Q
  2. Only Q and R
  3. Only Q
  4. Only P and R
Objective Type Questions

Answer:

Only P and R

Reason — Yoga, exercise, deep breathing and meditation are among the few methods that help manage stress or tension.

Short Answer Questions

9 questions

Question 1(a)

Define Endocrine glands.

Short Answer Questions

Answer:

Endocrine glands are ductless glands that secrete hormones directly into the bloodstream.

Question 1(b)

Define Cretinism.

Short Answer Questions

Answer:

Cretinism is a condition resulting from a deficiency of thyroid hormone in fetal or early life, characterized by intellectual disability, short stature and mental retardation.

Question 1(c)

Define Glucagon.

Short Answer Questions

Answer:

Glucagon is a hormone produced by the pancreas which raises the concentration of glucose by breaking glycogen in the liver.

Question 1(d)

Define Adolescence.

Short Answer Questions

Answer:

The period of life, when the body undergoes changes, leading to reproductive maturity, is called adolescence. In other words, adolescence is transitional phase of growth and development between childhood and adulthood.

Question 1(e)

Define Puberty.

Short Answer Questions

Answer:

Puberty is the period during which immature reproductive system in boys and girls matures and becomes capable of reproduction.

Question 1(f)

Define Hormone

Short Answer Questions

Answer:

Hormone is a regulatory substance produced in an organism and transported in tissue fluids such as blood to stimulate specific cells or tissues into action.

Question 2

In table given below, fill in the blanks by naming endocrine glands, the hormones they secrete, and the function they perform, in a normal person.

S.No.Name of the glandHormone producedFunction
1.Thyroid..............................
2................Insulin...............
3...............................Prepares the body for action
4................Growth Hormone...............
Short Answer Questions

Answer:

S.NoName of the glandHormone producedFunction
1.ThyroidThyroxineControl of metabolic rate
2.PancreasInsulinRegulation of sugar in blood.
3.Adrenal MedullaAdrenalinePrepares the body for action
4.PituitaryGrowth HormoneSpeeds up growth

Question 3

Write the exact locations of the following :

(a) Thyroid gland

(b) Adrenal gland

(c) Pancreas

(d) Pituitary gland

(e) Adam's apple

Short Answer Questions

Answer:

(a) Thyroid gland — The thyroid gland is located on either side of the wind pipe, just below the larynx.

(b) Adrenal gland — The adrenal glands are located on top of each kidney like caps.

(c) Pancreas — The pancreas is located behind the stomach.

(d) Pituitary gland — The pituitary gland is located at the base of the brain, below the hypothalamus.

(e) Adam's apple — The Adam's apple is located in the protruding part of the throat.

Question 4

Name the source and the function of each of the following hormones:

 HormoneSourceFunction
(a)Glucagon..............................
(b)Thyroxine..............................
(c)Adrenaline..............................
(d)Insulin..............................
(e)Cortisone..............................
Short Answer Questions

Answer:

 HormoneSourceFunction
(a)GlucagonPancreasBreakdown of glycogen to glucose. Raises sugar in the blood.
(b)ThyroxineThyroid glandControl of metabolic Rate .
(c)AdrenalineAdrenal MedullaPrepare the body to face emergency, stress.
(d)InsulinPancreasRegulation of sugar in blood.
(e)CortisoneAdrenal cortexInfluence carbohydrate, fat and protein metabolism. Regulate the salt and water balance in the body.