KnowledgeBoat Logo
OPEN IN APP

Chapter 12

The Endocrine System

Class 10 - Selina Concise Biology Solutions


Multiple Choice Type

(Select the most appropriate option in each case)

Question 1

A gland having endocrine as well as exocrine function is

  1. Pituitary
  2. Thyroid
  3. Pancreas ✓
  4. adrenal

Question 2

Exophthalmic goiter is caused due to the overactivity of

  1. thymus
  2. thyroid ✓
  3. parathyroid
  4. adrenal cortex

Question 3

The deficiency of ADH causes:

  1. diabetes mellitus
  2. diabetes insipidus ✓
  3. dwarfism
  4. acromegaly

Very Short Answer Type

Question 1

Name the following:

(a) The hormone produced by adrenal medulla.

(b) The condition caused by the over secretion of insulin.

(c) The hormone secreted by β (beta) cells of the islets of Langerhans.

(d) The interconnection between the two lobes of thyroid gland (technical term).

(e) The hormone whose under secretion causes more urine formation.

(f) The hormone which stimulates the entire sympathetic nervous system.

Answer

(a) Adrenaline

(b) Hypoglycemia

(c) Insulin

(d) Isthmus

(e) Anti-diuretic hormone (Vasopressin)

(f) Adrenaline

Question 2

What would a child suffer from, if there was hyposecretion from his thyroid?

Answer

If there was hyposecretion of the thyroid gland in a child, the child will suffer from cretinism. The symptoms of cretinism are dwarfism, mental retardation, etc.

Question 3

Choose the odd one out from each series:

(a) The glands - thyroid, adrenal, pituitary, prostate

(b) The conditions - cretinism, myxoedema, goiter, scurvy

(c) The hormones- insulin, glucagon, cretinism, thyroxine

(d) The hormonal sources - adrenal cortex, adrenal medulla, cortisone, pituitary

Answer

(a) Prostate is the odd one out here because Thyroid, Adrenal and Pituitary are all endocrine glands whereas Prostrate is an exocrine gland.

(b) Scurvy is the odd one out here because cretinism, myxoedema and goiter are caused due to the insufficient secretion of thyroxine whereas scurvy is a condition caused by a severe lack of vitamin C in the diet.

(c) Cretinism is the odd one out here because Insulin and Glucagon are the two hormones primarily responsible for maintaining homeostasis of blood glucose levels. Additional regulation is mediated by Thyroxine whereas Cretinism is a condition caused by Hypothyroidism that affects the growth of children showing dwarfism and mental retardation.

(d) Cortisone is the odd one out here because Adrenal Cortex, Adrenal Medulla and Pituitary are endocrine glands whereas Cortisone, is a hormone produced by the Adrenal Cortex that suppresses inflammation.

Question 4

Match the items of column I with those of column II.

Column IColumn II
(i) 'b' (beta) cells of islets of Langerhans(a) Condition due to under secretion of thyroxine in adults.
(ii) Thyroid(b) Undersecretion of glucocorticoids
(iii) Cretinism(c) Exophthalmic goitre
(iv) Addison's disease(d) Increases heart beat
(v) Hyperthyroidism(e) Thyroxine
(vi) Myxoedema(f) Adrenal cortex
(vii) Adrenaline(g) Insulin
(viii) Cortisone(h) Undersecretion of thyroxine in a child

Answer

Column IColumn II
(i) Beta cells of islets of Langerhans(g) Insulin
(ii) Thyroid(c) Thyroxine
(iii) Cretinism(h) Under secretion of thyroxine in a child
(iv) Addison's disease(b) Undersecretion of glucocorticoids
(v) Hyperthyroidism(e) Exophthalmic goitre
(vi) Myxoedema(a) condition due to undersecretion of thyroxine in adults
(vii) Adrenaline(d) Increases heart beat
(viii) Cortisone(f) Adrenal cortex

Question 5

Match the conditions in column A with the cause in column B.

A (Condition)B (Cause)
(a) Dwarfism and mental retardation(i) Excess of glucose in blood
(b) Diabetes mellitusii. Oversecretion of growth hormone
(c) Shortage of glucose in bloodiii. Insulin shock
(d) Gigantismiv. Oversecretion of thyroxine
(e) Enlargement of breasts in adult malesv. Hypothyroidism in a child.
(f) Exophthalmic goitrevi. Over secretion of cortical hormones

Answer

A (Condition)B (Cause)
(a) Dwarfism and mental retardationv. Hypothyroidism
(b) Diabetes mellitusi. Excess of glucose in blood
(c) Shortage of glucose in bloodiii. Insulin shock
(d) Gigantismii. Over secretion of growth hormone
(e) Enlargement of breasts in adult malesvi. Over secretion of cortical hormones
(f) Exophthalmic goitreiv. Over secretion of thyroxine.

Question 6

Identify the odd one in each of the following and mention what the rest are:

(a) Larynx; glucagon; testosterone; prolactin

(b) Adrenaline; penicillin; insulin; thyroxine

(c) Stomach; ileum; liver; adrenaline

(d) TSH; GH; ADH; insulin

(e) Iodine; cretinism; goitre; myxoedema

Answer

(a) Larynx is the odd one here because glucagon; testosterone and prolactin are hormones whereas Larynx is the sound box.

(b) Penicillin is the odd one here because adrenaline; insulin; thyroxine are hormones whereas Penicillin is an antibiotic.

(c) Adrenaline is the odd one here because stomach, ileum and liver are the organs of the digestive system whereas Adrenaline is a hormone.

(d) Insulin is the odd one here because TSH, GH, ADH are the hormones secreted by the pituitary gland whereas Insulin is secreted by the pancreas.

(e) Iodine is the odd one here because cretinism, goitre, myxoedema are the conditions which occur due to undersecretion of thyroxine (Hypothyroidism) whereas Iodine is required for the synthesis of thyroxine hormone.

Question 7

Given below are group of terms. In each group the first pair indicates the relationship between the two terms. Suggest the suitable word(s) for the fourth place.

(a) Beta cells : Insulin :: Alpha cells : ………………….

(b) Children : Cretinism :: Adults : ………………….

(c) Undersecretion : Dwarfism :: Oversecretion : ………………….

(d) Diabetes mellitus : Insulin :: Diabetes insipidus : ………………….

Answer

(a) Beta cells : Insulin :: Alpha cells : Glucagon.

(b) Children : Cretinism :: Adults : Myxoedema.

(c) Undersecretion : Dwarfism :: Oversecretion : Gigantism.

(d) Diabetes mellitus : Insulin :: Diabetes insipidus : Antidiuretic hormone (ADH).

Short Answer Type

Question 1

Mention the name of diseases based on the clues/ symptoms given below:

(a) Urine is loaded with sugar.

(b) Swelling in the neck.

(c) Dwarfism and mental retardation in children.

(d) Eyes are protruded.

(e) Excessive growth of bones in the face, hands and feet.

Answer

a) Hyperglycemia

b) Simple goitre

c) Cretinism

d) Exophthalmic goitre

e) Acromegaly in adults and gigantism in children.

Question 2

Write the exact location of each of the following glands:

(a) Thyroid

(b) Adrenal

(c) Pancreas

(d) Pituitary

Answer

(a) Thyroid — It is situated in the front part of the neck just below the larynx.

(b) Adrenal — It is present as a cap on the top of each kidney.

(c) Pancreas — It is located behind the stomach in the upper left abdomen.

(d) Pituitary — It hangs from the base of the mid-brain below the hypothalamus.

Question 3

Name the following:

(a) Three hormones secreted from islets of langerhans of pancreas.

(b) Two types of cortical hormones.

(c) Six hormones secreted from anterior pituitary.

(d) Two hormones secreted from posterior pituitary.

(e) The emergency hormone.

Answer

(a) Three hormones secreted from islets of Langerhans of pancreas are

  1. Insulin
  2. Glucagon
  3. Somatostatin

(b) Two types of cortical hormones are

  1. Glucocorticoids
  2. Mineralocorticoids

(c) Six hormones secreted from anterior pituitary are

  1. Growth hormone (somatostatin)
  2. Prolactin
  3. Adreno-corticotropic hormone (ACTH)
  4. Thyroid stimulating hormone (TSH)
  5. Follicle stimulating hormone (FSH)
  6. Luteinizing hormone (LH)

(d) Two hormones secreted from posterior pituitary are

  1. Antidiuretic hormone (ADH) or Vasopressin
  2. Oxytocin

(e) The emergency hormone is

  1. Adrenaline

Question 4

Write the main function of each of the following hormones.

HormonesFunctions
(a) Thyroxine……………………………
(b) Adrenaline……………………………
(c) Insulin……………………………
(d) Glucagon……………………………
(e) Vasopressin……………………………

Answer

HormonesFunctions
(a) ThyroxinePromotes tissue metabolism, growth and differentiation.
(b) AdrenalineCauses stimulation of sympathetic nervous system. Prepares body for any emergency.
(c) InsulinReduces the blood sugar level.
(d) GlucagonIncreases the blood sugar level.
(e) VasopressinIncreases reabsorption of water from kidneys, contraction of blood vessels causing rise in blood pressure.

Question 5

Name the hormones responsible for the given functions.

FunctionsHormones
(a) Contraction of uterine muscles during child birth……………………………
(b) Maintenance of corpus luteum……………………………
(c) Milk formation and secretion……………………………
(d) Development of external sex characters in males……………………………
(e) Stimulation of sympathetic nervous system…………………………….

Answer

FunctionsHormones
(a) Contraction of uterine muscles during child birthOxytocin
(b) Maintenance of corpus luteumLuteinizing hormone (LH)
(c) Milk formation and secretionProlactin
(d) Development of external sex characters in malesTestosterone
(e) Stimulation of sympathetic nervous systemAdrenaline

Question 6

If you stand to make your maiden speech before a large audience, your mouth dries up and heart rate increases. What brings about these changes?

Answer

When we stand to make our maiden speech before a large audience, our mouth dries up and heart rate increases and it is due to secretion of adrenaline hormone by adrenal glands. Adrenaline is the hormone which prepares the body to meet any emergency situation. Adrenaline makes the heart beat faster. At the same time, it stimulates the constriction of the arterioles of the digestive system reducing the blood supply of the digestive system which makes the mouth dry.

Question 7

Given below is a table designed to give the names of the glands, the hormones produced, their chief functions, the effects of over secretion and under secretion in respect of thyroid, pituitary and pancreas. Fill up the blanks 1-13.

S.No.Source Gland cellsHormone producedChief functionEffect of oversecretionEffect of undersecretion
1.(1) --------Thyroxine(2) ----(3)----(4)---
2.Beta cells of Islets of Langerhans(5) ------Promotes glucose utilisation by the body cells(6) ----(7) ------
3.(8) --------Growth hormone(9) ----(10) ---Dwarfism
4.(11) ------VasopressinIncreases reabsorption of water from kidney tubules(12) -------(13) ------

Answer

S.No.Source Gland cellsHormone producedChief functionEffect of over secretionEffect of under secretion
1.ThyroidThyroxineRegulates basal metabolismExophthalmic goiterSimple goiter, cretinism in children and myxoedema in adults
2.Beta cells of Islets of LangerhansInsulinPromotes glucose utilization by the body cellsHypoglycemiaDiabetes mellitus
3.Anterior pituitaryGrowth hormonePromotes growth of the whole bodyGigantismDwarfism
4.Posterior pituitaryVasopressinIncreases reabsorption of water from kidney tubuleMore concentrated and less amount of urine, Elevation of blood pressureDiabetes insipidus

Question 8

Complete the following table by filling in the blanks numbered 1 to 7.

GlandHormone secretedEffect on body
(1) -----------(2) -------Regulates basal metabolism
Pancreas ("beta" cells)(3) -------Controls blood sugar
(4) ------------(5) --------Increases heart beat
(6) ------------Thyroid stimulating hormone(7) ------------

Answer

GlandHormone secretedEffect on body
ThyroidThyroxineRegulates basal metabolism
Pancreas ("beta" cells)InsulinControls blood sugar level
Adrenal glandAdrenalineIncreases heart beat
Anterior pituitaryThyroid stimulating hormoneStimulates thyroxine secretion

Question 9

Complete the following table by filling in the blank spaces numbered 1 to 8.

GlandSecretionsEffect on body
(1) ------------Oestrogen(2) -----
Alpha cells of islets of Langerhans(3) -------(4) -----
(5) ----------(6) -------Protruding eyes
(7) ----------(8) -------Gigantism

Answer

GlandSecretionsEffect on body
OvaryOestrogenDevelopment of secondary sexual characteristics
Alpha cells of islets of LangerhansGlucagonRaises blood sugar level
ThyroidHypersecretion of thyroxineProtruding eyes
Anterior pituitaryHypersecretion of Growth hormoneGigantism

Descriptive Type

Question 1

Define the following terms:

(a) Endocrine system

(b) Hormones

(c) Myxoedema

Answer

(a) Endocrine system — Endocrine system consists of several endocrine glands/glandular cells which activate each other and work as a system to bring about overall chemical coordination in the body.

(b) Hormones — Hormone is a secretion from some glandular part of the body, which is poured directly into blood and which acts on the target organs or cells of the same individual, bringing about coordination between distant parts of the body.

(c) Myxoedema — Myxoedema is a condition which occurs in adults due to hypothyroidism in which the person becomes sluggish with swelling of the face and hands.

Question 2

Distinguish between the following pairs:

(a) Exocrine and endocrine glands (manner of secretion)

(b) Enzymes and hormones (chemical composition and mode of action)

(c) Nervous control and hormonal control (transmission and effect)

(d) Diabetes mellitus and diabetes insipidus (cause and symptoms)

(e) Addison's disease and Cushing's syndrome (cause and sugar level)

Answer

(a) Difference between exocrine and endocrine glands (manner of secretion):

Exocrine glandsEndocrine glands
Secretions are carried through special ducts.Secretions are poured directly into the blood.

(b) Difference between enzymes and hormones (chemical composition and mode of action):

EnzymesHormones
Enzymes are protein in nature.Hormones are peptides, amines or steroids.
Enzymes are substrate specific. These are present in all cells and show their activity there.Hormones are specific to the target cell, tissue, or system. They are produced at one site and show their activities at other sites.

(c) Difference between nervous control and hormonal control (transmission and effect):

Nervous controlHormonal control
Effect is only short-lived.Effect is short term or long lasting.
Transmitted electro-chemically through nerve fibres and chemically across synapses.Transmitted chemically through blood.

(d) Difference between diabetes mellitus and diabetes insipidus (cause and symptoms):

Diabetes mellitusDiabetes insipidus
Caused due to insufficient secretion of insulin.Caused due to insufficient secretion of anti-diuretic hormone (ADH)
High concentration of sugar in blood.No sugar in urine

(e) Difference between Addison's disease and Cushing's syndrome (cause and sugar level):

Addison's diseaseCushing's syndrome
Caused due to hyposecretion of cortisoneCaused due to hypersecretion of cortisone
Low blood sugar levelHigh blood sugar level

Question 3(a)

Give reason:
Adrenaline is often described as the emergency hormone.

Answer

Adrenaline is known as the Emergency hormone because it prepares the body to meet any emergency situation, for "fight" i.e. to face danger or for "flight" i.e. to run away from it. Extra energy and strength is provided to the body in that situation. It stimulates the sympathetic nervous system. When excited or angry, the adrenal medulla produces a lot of Adrenaline preparing the body for any emergency.

Question 3(b)

Give reason:
Pituitary is popularly called as the master gland.

Answer

Pituitary is popularly called as the master gland because it controls the functioning of all the other endocrine glands.

Question 3(c)

Give reason:
People living in the low Himalayan hilly regions often suffer from goitre.

Answer

People living in the low Himalayan hilly regions often suffer from goitre because iodine is deficient in the soil of those regions and hence, in the food grown there. Insufficient iodine produces less thyroxine which results in goitre.

Question 3(d)

Give reason:
Simple goitre can be prevented by using iodised salt in food.

Answer

Iodised salt contains iodine which is an active ingredient in the production of thyroxine. Hence, it is recommended to use iodised salt in food to prevent simple goitre.

Question 4

Do you agree with the statement- "All hormones are chemical signals"? Yes/No. Justify your answer.

Answer

Yes, all hormones are chemical signals. Hormones are chemically peptides, amines or steroids in nature and they regulate our physiological process through chemical means. They are also involved in regulating the metabolism of the body. They can bring about specific chemical changes during metabolic process. Therefore hormones can be termed as 'chemical messengers'.

Structured / Application / Skill Type

Question 1

Study the diagram given below and then answer the questions that follow:

Study the diagram and then answer the questions. Name the cells of the pancreas that produce (1) glucagon (2) insulin. State the main function of (1) glucagon and (2) insulin. Why is the pancreas referred to as an exo-endocrine gland? Why is insulin not given orally but is injected into the body? What is the technical term for the cells of the pancreas that produce endocrine hormones? Where in the body is the Pancreas located? The Endocrine System, Concise Biology Solutions ICSE Class 10.

(a) Name the cells of the pancreas that produce (1) glucagon (2) insulin.

(b) State the main function of (1) glucagon and (2) insulin.

(c) Why is the pancreas referred to as an exo-endocrine gland?

(d) Why is insulin not given orally but is injected into the body?

(e) What is the technical term for the cells of the pancreas that produce endocrine hormones?

(f) Where in the body is the Pancreas located?

Answer

(a) Glucagon is produced by the Alpha cells of the islets of Langerhans.
Insulin is produced by the Beta cells of the islets of Langerhans.

(b) The main function of Glucagon is to raise the blood glucose levels by stimulating the breakdown of glycogen to glucose in the liver.
The main function of Insulin is to maintain the levels of glucose (sugar) in the blood.

(c) Exocrine glands are those glands which deliver their secretions to the target through ducts. An endocrine gland is one which does not pour its secretions into a duct but directly into the blood. As an exocrine gland the pancreas secrete pancreatic juices into the duodenum for digestion. As an endocrine gland, it has special groups of hormone-secreting cells called Islets of Langerhans which are scattered in the entire gland. The islet cells produce three hormones — insulin, glucagon and somatostatin which are poured directly into the blood. Hence, the pancreas is an exo-endocrine gland.

(d) Insulin is not administered orally because the digestive juices degrade insulin making it ineffective. Hence, to avoid its degradation, Insulin is injected into the body.

(e) Islets of Langerhans

(f) The Pancreas is located in the abdomen behind the stomach.

Question 2

Given alongside is a portion from the human body showing some important structure in ventral (front) view.

Given alongside is a portion from the human body showing some important structure in ventral (front) view. Where is this portion located in the body? Name the structures numbered 1-3. State one main function of each of the structures named above. Is there any duct to carry the secretions from the structure numbered 2? If so, give its name. The Endocrine System, Concise Biology Solutions ICSE Class 10.

(a) Where is this portion located in the body?

(b) Name the structures numbered 1-3.

(c) State one main function of each of the structures named above.

(d) Is there any duct to carry the secretions from the structure numbered 2? If so, give its name.

Answer

(a) This portion is located in the neck region above the sternum.

(b) The structures numbered 1-3 are:

  • 1 → Larynx
  • 2 → Thyroid gland
  • 3 → Trachea

(c) One main function of each of these structures is:

  1. Larynx is the voice box containing vocal cords. It helps in producing sound.
  2. Thyroid gland produces thyroxine and calcitonin which are essential hormones.
  3. Trachea is the wind pipe that helps in passing air to and from the respiratory system while breathing.

(d) Structure 2 is the thyroid gland. It is an endocrine gland, so it is ductless and pours its secretions directly into the blood. Hence, there is no duct.

Question 3

Given below is an outline diagram of human body showing position of certain organs.

Given below is an outline diagram of human body showing position of certain organs. Name the parts numbered 1 to 4. What is common to all these parts in regard to the nature of their functions? Name the nutrient element which is essential for the normal working of part 2. The Endocrine System, Concise Biology Solutions ICSE Class 10.

(a) Name the parts numbered 1 to 4.

(b) What is common to all these parts in regard to the nature of their functions?

(c) Name the nutrient element which is essential for the normal working of part 2.

Answer

(a) The parts numbered 1-4 are:

  • 1 → Pituitary gland
  • 2 → Thyroid gland
  • 3 → Pancreas
  • 4 → Adrenal Glands

(b) All the glands shown in the above diagram are endocrine glands. They secrete essential hormones and pour their secretions directly into the blood.

(c) Iodine is essential for the normal working of Thyroid gland.

Question 4

Given below are two diagrams (one is correct, the other one is somewhat incorrect) showing the transport of a hormone from its source gland/cell to the target organ/cell.

(a) Which one has the error — A or B?

(b) What is the error?

Given below are two diagrams (one is correct, the other one is somewhat incorrect) showing the transport of a hormone from its source gland/cell to the target organ/cell. Which one has the error - A or B? What is the error? The Endocrine System, Concise Biology Solutions ICSE Class 10.

Answer

(a) Diagram A has error.

(b) In diagram B hormones secreted by endocrine gland are carried to all parts as they may have one or more target sites at a time which is correct. But in diagram A hormones secreted by endocrine gland are moving in a single direction towards the target cell which is incorrect.

Think and Connect

Question 1

Compare the hormonal response with the nervous response with respect to their speed, transmission and general nature of changes brought about.

Answer

Hormonal ResponseNervous Response
Usually slow.Immediate/Rapid.
Transmitted chemically through blood.Transmitted electro-chemically through the nerve fibres and chemically across synapses.
Affects different organs (widespread in body).Affects only the particular muscles or the gland (local).
Effect is short term or long-lasting.Effect only short-lived.
Can affect growth.Cannot affect growth.
Can bring about specific chemical changes and regulates metabolism.Does not influence chemical changes and cannot regulate metabolism.
Cannot be modified by learning from previous experience.Can be modified to some extent by learning from previous experience.

Question 2

Mention three important differences between the action of hormones and that of nerves in the regulatory mechanism of our body.

Answer

Action of HormonesAction of Nerves
The effect of hormones can be short-lived or long lasting.The effect of nervous response is always short-lived.
Cannot be modified by the previous learning experiences.Can be modified by the previous learning experiences.
Affects different organs (widespread in body).Affects only the particular muscles or the gland (local).
PrevNext