Selina Concise Solutions for ICSE Class 10 Biology Chapter 9 Endocrine Glands

Multiple Choice Type

Question 1. A gland having endocrine as well as exocrine function is
(a) pituitary
(b) thyroid
(c) pancreas
(d) adrenal
Answer: (c) pancreas
In simple words: The pancreas is like a dual-purpose factory that makes both hormones (like insulin) that go directly into blood and digestive juices that go through tubes to help digest food.

📝 Teacher's Note: Use the analogy of a factory with two production lines - one sends products directly to customers (hormones to blood) and another uses delivery trucks (ducts for digestive enzymes). Students often confuse this with other glands that only have one function.

🎯 Exam Tip: Remember "Pan-creas = Pan-dual function" - it's the only major gland mentioned that has both endocrine and exocrine functions.

Question 2. Exophthalmic goitre is caused due to the over activity of
(a) thymus
(b) thyroid
(c) parathyroid
(d) adrenal cortex
Answer: (b) thyroid
In simple words: When the thyroid gland works too much, it causes bulging eyes and swelling in the neck area - this condition is called exophthalmic goitre.

📝 Teacher's Note: Show students pictures of exophthalmic goitre to help them remember the characteristic bulging eyes. Emphasize that "exo" means outward, relating to the protruding eyes.

🎯 Exam Tip: Link "exophthalmic" with "excess thyroid activity" - both start with "ex" to help remember the connection.

Question 3. The secretion of ADH (anti-diuretic hormone) is inhibited by
(a) emotion and stress
(b) nicotine
(c) alcohol
(d) morphine
Answer: (c) alcohol
In simple words: Alcohol stops the hormone that helps your body hold onto water, which is why people need to urinate more frequently when they drink alcohol.

📝 Teacher's Note: This is a good opportunity to discuss the harmful effects of alcohol on body functions. Students can relate to the real-world observation of frequent urination after alcohol consumption.

🎯 Exam Tip: Remember "Alcohol Disrupts Hydration" - ADH helps retain water, alcohol blocks it, causing dehydration.

Very Short Answer Type

Question 1. Name the following:
(a) The three hormones produced by pancreas
(b) The hormone produced by adrenal medulla
(c) The condition caused by the over secretion of insulin
(d) The hormone secreted by β (beta) cells of the islets of Langerhans
(e) The hormone which increases blood pressure
(f) The hormone causing more urine formation
(g) The hormone which stimulates the entire sympathetic nervous system
Answer:
(a) Insulin, glucagon, somatostatin
(b) Adrenaline
(c) Hypoglycemia
(d) Insulin
(e) Adrenaline
(f) Anti-diuretic hormone (Vasopressin)
(g) Adrenaline
In simple words: The pancreas makes three different hormones, and adrenaline from the adrenal gland is like the body's emergency alarm system that affects many body functions at once.

📝 Teacher's Note: Create a hormone chart on the board showing gland → hormone → function. Students often confuse which cells produce which hormones, so emphasize beta cells = insulin specifically.

🎯 Exam Tip: Notice that adrenaline appears in multiple answers - it's a key hormone that affects blood pressure, stress response, and nervous system activation.

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.
In simple words: When a child's thyroid gland doesn't make enough hormone, the child doesn't grow properly in body or mind - this serious condition is called cretinism.

📝 Teacher's Note: Emphasize the importance of early detection and treatment. Explain that this is why newborn screening for thyroid function is crucial in many countries.

🎯 Exam Tip: Remember "Child + Hypo thyroid = Cretinism" and always mention both physical (dwarfism) and mental effects for full marks.

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 medualla, cortisone, pituitary
Answer:
(a) Prostate
(b) Scurvy
(c) Cretinism
(d) Cortisone
In simple words: In each group, one item doesn't belong with the others - like finding the fruit in a list of vegetables.

📝 Teacher's Note: Use this exercise to reinforce classification skills. Have students explain why each odd one doesn't belong to strengthen their understanding of categories.

🎯 Exam Tip: Always identify what the group represents first, then find what doesn't fit that category.

Question 4. Identify the odd one in each of the following and mention what the rest are:
(a) Larynx; glucagon; testosterone; prolactin
(b) Adrenaline; penicillin; insulin; thyroxin
(c) Stomach ; ileum; liver; adrenaline
(d) TSH; GH; ADH; Insulin
(e) Iodine, cretinism, goiter, myxedema
Answer:
(a) Larynx
Reason- Larynx is the sound box while the rest three i.e. glucagon; testosterone and prolactin are hormones.
(b) Penicillin
Reason - Penicillin is an antibiotic while adrenaline; insulin; thyroxine are hormones.
(c) Adrenaline
Reason - Adrenaline is a hormone while the stomach, ileum and liver are the organs of the digestive system.
(d) Insulin
Reason- Insulin is secreted by the pancreas while TSH, GH, ADH are the hormones secreted by the pituitary gland.
(e) Iodine
Reason- Iodine is required for the synthesis of thyroxine hormone. While cretinism, goitre, myxoedema are the deficiencies occur due to the deficiency of thyroxine.
In simple words: Each group has items that belong together except one - like having three types of fruit and one vegetable in the same basket.

📝 Teacher's Note: This question tests multiple classification systems. Emphasize that students must not only identify the odd one but also explain what category the others belong to.

🎯 Exam Tip: Always give a complete reason stating both what the odd one is AND what category the others belong to for full marks.

Question 5. Match the items of column I with those of column II

In simple words: This matching exercise connects body parts with their functions, like matching keys to the right locks.

📝 Teacher's Note: Use this as a comprehensive review exercise. Have students create their own matching questions to test classmates' understanding.

🎯 Exam Tip: Read all options first, then match the most obvious pairs first, leaving the difficult ones for last.

Question 6. match the conditions in column A with the cause in column B.

In simple words: Every medical condition has a specific cause - like how different types of car problems have different reasons.

📝 Teacher's Note: Emphasize cause-and-effect relationships. Students should understand that hormone imbalances (too much or too little) cause specific symptoms.

🎯 Exam Tip: Focus on whether conditions are caused by "hyper" (over-secretion) or "hypo" (under-secretion) of hormones.

Short Answer Type

Question 1. Mention which of the statements are true (T) and which are false (F). Give reason in support of your answer.
(a) Adrenaline is often described as emergency hormone
(b) There are two kinds of diabetes (mild and severe) related with two different hormones.
(c) Simple goiter can be prevented by using iodised salt in food.
(d) Pituitary is popularly called the master gland
(e) Harmones 'obey' the commands like 'enough, slow down or 'two little, speed up'.
(f) Gigantism and dwarfirm in humans basically depend on the qualtity and quantity of the food eaten during early growing age.
Answer:
(a) True
Reason- Adrenaline is described as emergency hormone because during any emergency situation more adrenaline is secreted which makes the heart beat faster, increases the breathing, releases more glucose into the blood stream to fulfill the energy requirement.
(b) False
Reason- The two different kinds of diabetes are diabetes insipidus caused due to insufficient secretion of vasopressin and the other is 'diabetes mellitus' caused due to hyposecretion of insulin but they cannot be described as mild and severe.
(c) True
Reason-Iodine is an active ingredient in the production of the thyroxine hormone.
(d) True
Reason- Pituitary gland controls the functioning of all the other endocrine glands.
(e) True
Reason- Hormones are poured directly into blood the blood stream and control physiological processes by chemical means. Their action depends on the feedback mechanism.
(f) True
Reason- Gigantism and dwarfism are controlled by the growth hormone from the pituitary gland. Growth hormone is much more active in children for their normal body growth along with which necessary substance required for the synthesis of growth hormone need to be consumed.
In simple words: These statements test your understanding of how hormones work like the body's chemical messengers and control systems.

📝 Teacher's Note: Use statement (b) to clarify the difference between diabetes insipidus and diabetes mellitus - students often think there's only one type of diabetes.

🎯 Exam Tip: For true/false questions, always provide specific scientific reasons, not just general statements.

Question 2. How do endocrine glands differ from other glands?
Answer: Endocrine glands are ductless glands, means they pour their secretion i.e. hormones directly into the blood stream while the other glands are exocrine glands which have ducts. Through ducts they pour their secretions (not hormones) into the blood stream.
In simple words: Endocrine glands are like direct injection systems that put hormones straight into blood, while other glands use tubes (ducts) to send their products to specific places.

📝 Teacher's Note: Draw two diagrams - one showing ductless glands releasing directly into blood vessels, another showing ducted glands with tubes leading to target organs.

🎯 Exam Tip: Always mention "ductless" and "directly into bloodstream" as key characteristics of endocrine glands.

Question 3. Mention any two differences between a hormone and an enzyme.
Answer: Hormones unlike enzymes are secreted by the endocrine glands only. Also the hormones unlike the enzymes are poured directly into the blood. Hormones can be peptides, steroids, amine but all enzymes are proteins.
In simple words: Hormones are chemical messengers made by special glands and travel through blood, while enzymes are protein workers that speed up reactions and can be made by many body parts.

📝 Teacher's Note: Create a comparison chart showing source, transport method, and chemical nature of both hormones and enzymes.

🎯 Exam Tip: Remember the key differences: source (endocrine glands vs various cells), transport (blood vs local), and chemistry (various types vs proteins only).

Question 4. Do you agree with the statement – " All hormones are chemical signals"? Yes / No . Justify your answer.
Answer: Chemically hormones are peptides, amines or steroids. They are 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'.
In simple words: Yes, hormones are chemical signals because they are made of chemicals and carry messages between different parts of the body through the bloodstream.

📝 Teacher's Note: Explain that hormones work like a postal service - they carry chemical "letters" with specific instructions to target organs.

🎯 Exam Tip: Always say "Yes" and explain that hormones are chemical messengers that regulate body processes through chemical means.

Question 5. Why is iodine as a nutrient, important to our body?
Answer: Iodine is an active ingredient in the production of the thyroxine hormone secreted by the thyroid gland. Thyroxine hormone is a very essential hormone for our body. In case of its abnormal secretions a person may suffer certain severe disorders. Therefore, it is an important nutrient for our body.
In simple words: Iodine helps your thyroid gland make thyroxine hormone, which controls how fast your body uses energy. Without enough iodine, your body cannot function properly.

📝 Teacher's Note: Use the analogy of iodine being like fuel for a car engine - without it, the thyroid "engine" cannot produce the hormones needed to run the body's metabolism smoothly.

🎯 Exam Tip: Always mention that iodine is essential for thyroxine production by the thyroid gland and link it to metabolic disorders for full marks.

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: 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.
In simple words: When you feel scared or nervous, your adrenal glands release adrenaline hormone. This hormone speeds up your heart and reduces saliva production, making your mouth dry.

📝 Teacher's Note: Connect this to students' real experiences like stage fright or exam stress. Explain that this is the "fight or flight" response that helped our ancestors survive dangers.

🎯 Exam Tip: Mention adrenaline hormone specifically and explain both effects - increased heart rate and reduced blood flow to digestive system causing dry mouth.

Question 7. If one adrenal gland is removed, the other one gets enlarged to some extent. How do you explain this change?
Answer: If one adrenal gland is removed, the other one gets enlarged. This is to meet the requirement of hormones produced by the body.
In simple words: When one adrenal gland is removed, the remaining gland grows bigger to produce enough hormones for the whole body, like one worker doing the job of two.

📝 Teacher's Note: Explain this as compensatory hypertrophy - the body's amazing ability to adapt. Compare it to how muscles grow when they work harder.

🎯 Exam Tip: Use the term "compensatory enlargement" and explain that it maintains hormone levels in the body.

Question 8. Name the two kinds of diabetes? Mention their symptoms and the causes.
Answer: 1. Diabetes mellitus:
Cause - under secretion of Insulin hormone
Symptoms - excretion of great deal of urine with sugar, Person feels thirsty and loss of weight. In severe cases, the person may lose the eye sight.
2. Diabetes insipidus:
Cause - Under secretion of Anti-diuretic hormone
Symptoms - frequent urination resulting in loss of water from body and the person feels thirsty.
In simple words: Diabetes mellitus happens when your pancreas doesn't make enough insulin, causing sugar in urine. Diabetes insipidus happens when your brain doesn't make enough ADH, causing too much urination without sugar.

📝 Teacher's Note: Emphasize the difference between the two types - one involves blood sugar (mellitus) and one involves water balance (insipidus). Students often confuse these.

🎯 Exam Tip: Clearly state both types with their specific hormones - insulin for mellitus and ADH for insipidus. Mention sugar in urine only for mellitus.

Question 9. People living in the low Himalayan hilly regions often suffer from goiter. What could be the possible reason for it?
Answer: The Himalayan soil is deficient in iodine. Thus, the food grown in such soil also becomes iodine deficient. Due to this reason, when Himalayan people consume iodine deficient food, they do not get the proper intake of iodine. Therefore, people living in the low Himalayan hilly regions often suffer from goitre.
In simple words: The soil in Himalayan regions lacks iodine, so crops grown there also lack iodine. When people eat this food, they don't get enough iodine, causing their thyroid gland to swell (goiter).

📝 Teacher's Note: Connect this to the importance of iodized salt programs. Explain how geographic factors can affect nutrition and health in different regions.

🎯 Exam Tip: Mention the sequence: iodine-deficient soil → iodine-deficient food → inadequate iodine intake → goiter formation.

Question 10. 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
Answer:

In simple words: This table shows how different glands make specific hormones, and what happens when they make too much or too little of these hormones.

📝 Teacher's Note: Use this table to help students understand the concept of hormone balance - too much or too little of any hormone causes problems.

🎯 Exam Tip: Learn the specific disorders for hyper and hypo secretion of each hormone. Remember that "hyper" means too much, "hypo" means too little.

Question 11. Complete the following table by filling in the blanks numbers 1 to 7?
Answer:

In simple words: Each gland produces specific hormones that control different body functions like metabolism, blood sugar, heart rate, and other gland activities.

📝 Teacher's Note: Emphasize the concept of hormone hierarchy - how one gland (pituitary) can control another gland (thyroid) through its hormones.

🎯 Exam Tip: Remember the gland-hormone-function triplets. TSH from pituitary controls thyroid gland function.

Question 12. Complete the following table by filling in the blank spaces numbered 1 to 8:
Answer:

In simple words: This table shows how different hormones affect the body - some control sexual development, blood sugar, and growth, while excess amounts cause specific problems.

📝 Teacher's Note: Point out that the last two rows show abnormal hormone levels and their effects. Help students distinguish between normal hormone functions and disease conditions.

🎯 Exam Tip: Note that alpha cells produce glucagon (raises blood sugar) while beta cells produce insulin (lowers blood sugar) - they have opposite effects.

Long Answer Type:

Question 1. Compare the hormonal response with the nervous response with respect to their speed, transmission and the general nature of changes brought about.
Answer:

In simple words: Hormones work slowly through blood like mail delivery, while nerves work instantly like phone calls. Hormones cause chemical changes in the body, nerves just send signals.

📝 Teacher's Note: Use analogies like postal system vs telephone to explain the speed difference. Demonstrate with examples like adrenaline rush (hormonal) vs reflexes (nervous).

🎯 Exam Tip: Always compare both systems in a tabular format and mention speed, transmission method, and type of changes for full marks.

Question 2. Mention three important differences between the action of hormones and that of nerves in the regulatory mechanism of our body.
Answer:

In simple words: Hormones affect many body parts at once and can last long, while nerves target specific areas quickly. You can train your nerves through practice, but not your hormones.

📝 Teacher's Note: Explain that hormones broadcast to the whole body like radio, while nerves are like direct phone calls to specific locations. Discuss how learning affects nerve responses but not hormone responses.

🎯 Exam Tip: Structure your answer in three clear points about target specificity, duration of effect, and modifiability by learning.

Structured / Application / Skill Type:

Question 1. Study the diagram given below and then answer the questions that follow:
(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 in 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: Alpha cells of the islets of Langerhans
Insulin: Beta cells of the islets of Langerhans
b. Insulin: It maintains the levels of glucose (sugar) in the blood.
Glucagon: It raises the blood glucose levels by stimulating the breakdown of glycogen to glucose in the liver.
c. An endocrine gland is one which does not pour its secretions into a duct, while an exocrine gland is a gland which pours its secretions into a duct. Because the pancreas produces hormones such as insulin, glucagon and somatostatin directly into the blood and not into a duct, it functions as an endocrine gland. Because it secretes the pancreatic juices for digestion via a duct, it functions as an exocrine gland. Hence, the pancreas is an exo-endocrine gland.
d. Insulin is not administered orally because the digestive juices degrade insulin, and thus the insulin is ineffective in the body.
e. Islets of Langerhans
f. The pancreas is located in the abdomen behind the stomach.
In simple words: The pancreas has special cells that make hormones (alpha and beta cells) and also makes digestive juices, so it does two different jobs. Insulin must be injected because stomach acid would destroy it if taken as pills.

📝 Teacher's Note: Emphasize the dual nature of pancreas and why injection is necessary for insulin. Use the analogy of pancreas being like a factory with two production lines.

🎯 Exam Tip: Remember alpha cells make glucagon (raises sugar) and beta cells make insulin (lowers sugar). Explain both endocrine and exocrine functions for the dual gland question.

Question 2. Given alongside is a portion from the human body showing some important structure in ventral (front) view.
(a) Where is this portion located in the body?
(b) Name the structure numbered 1 – 3
(c) state one main function of each of the structure 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) 1- Larynx, 2 - Thyroid gland, 3 - Trachea
(c) Larynx: Production of voice/sound
Thyroid gland: Secretes thyroxine hormone to regulate metabolism
Trachea: Conducts air to and from the lungs
(d) No, there is no duct to carry secretions from the thyroid gland because it is an endocrine gland that releases hormones directly into the bloodstream.
In simple words: This shows your neck area with the voice box, thyroid gland that controls body speed, and windpipe for breathing. The thyroid puts its hormones directly into blood, not through tubes.

📝 Teacher's Note: Use this diagram to reinforce the concept of endocrine vs exocrine glands. Point out how the thyroid gland is positioned strategically near major blood vessels.

🎯 Exam Tip: Clearly state that thyroid is an endocrine gland with no duct, and mention the specific location as neck region above sternum.

(c) Larynx is the voice box containing vocal cords. It helps in producing sound. Thyroid gland produces thyroxine and calcitonin which are essential hormones. 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. Given alongside is an outline diagram of human body showing position of certain organs.
(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) 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 thyroxine.
In simple words: These four glands are like chemical factories in your body that make special messengers called hormones. The thyroid gland needs iodine (found in salt) to work properly.

📝 Teacher's Note: Use a simple body diagram on the board and have students point to where they think each gland is located. Connect thyroid function to iodized salt in their diet to make it relatable.

🎯 Exam Tip: Always mention "endocrine glands secrete hormones directly into blood" for part (b) - this is the key phrase examiners look for. Remember iodine for thyroid function.

Question. Given below are two diagram (one is correct the other 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?
Answer:
(a) A
(b) Hormone secreted by the endocrine gland is shown in the image A to be moving only in one direction i.e. towards the target organ. But actually the hormones poured into the blood stream may have one or more target sites at a time. The arrows shown are carried to all parts by the blood and their effect is produced only in one or more specific parts.
In simple words: Diagram A is wrong because it shows hormones going to only one place, but in reality hormones travel everywhere in the blood and can affect multiple body parts at once.

📝 Teacher's Note: Compare hormone transport to a radio signal - it broadcasts everywhere but only certain "receivers" (target organs) respond. Use the analogy of throwing confetti that spreads everywhere but only sticks to certain surfaces.

🎯 Exam Tip: Emphasize that hormones are carried "to all parts by blood" but only affect specific target organs - this distinction between transport and action is crucial for full marks.