GSEB Class 11 Biology Solutions Chapter 22 Chemical Coordination and Integration

 

Question 1. Define the following.
1. Exocrine gland
2. Endocrine gland
3. Hormone
Answer:
1. Exocrine gland: The secretions of these glands are carried by ducts, for example, salivary glands and the liver.
2. Endocrine gland: These glands have no ducts, and their secretions are carried by the blood, for instance, the pituitary gland.
3. Hormone: A hormone is a secretion from a ductless gland that helps regulate and coordinate specific body functions.
In simple words: Exocrine glands use tubes (ducts) for their secretions, like saliva. Endocrine glands release directly into the blood without ducts, like the pituitary. Hormones are substances from ductless glands that control body processes.

Exam Tip: Clearly define each term, mentioning key characteristics such as the presence or absence of ducts and examples for better understanding.

 

Question 2. Diagrammatically indicate the location of the various endocrine glands in our body.
Answer: The endocrine glands and hormone-producing diffused tissues, which are cells found in various parts of our body, collectively form the endocrine system. The pituitary, pineal, thyroid, adrenal, pancreas, thymus, and gonads are the organized endocrine bodies within our body.
In simple words: Endocrine glands make hormones and are spread throughout the body. The pituitary, pineal, thyroid, adrenal, pancreas, thymus, and gonads are important ones.

Exam Tip: When describing the location of glands, it's helpful to name the major glands and mention that they are distributed across different body regions, forming a complex system.

 

Question 3. List the hormones secreted by the following:
1. Hypothalamus
2. Pituitary
3. Thyroid
4. Parathyroid
5. Adrenal
6. Pancreas
7. Testis
8. Over
9. Thymus
10. Atrium
11. Kidney
12. G-I-Tract
Answer:
1. Hypothalamus: Gonadotrophin (GnRH), Somatostatin
2. Pituitary: Growth Hormone (GH), Prolactin (PRL), thyroid-stimulating hormone (TSH), adrenocorticotropic hormone (ACTH), luteinizing hormone (LH) and follicle-stimulating hormone (FSH), melanocyte-stimulating hormone (MSH), Oxytocin, vasopressin, glucocorticoids, androgens, anti-diuretic hormone (ADH).
3. Thyroid: Thyroxine (T4) and triiodothyronine (T3), thyrocalcitonin (TCT).
4. Parathyroid: Parathyroid hormone (PTH)
5. Adrenal: Adrenaline or epinephrine and noradrenaline or norepinephrine (these are emergency hormones for 'Fight or Flight'), and corticoids.
6. Pancreas: Glucagon, insulin
7. Testis: Androgens (testosterone)
8. Ovary: Estrogen and progesterone
9. Thymus: Thymosins
10. Atrium: Atrial natriuretic factor (ANF)
11. Kidney: Erythropoietin
12. G-I-Tract: Gastrin
In simple words: Each part of the body listed produces specific chemical messages called hormones. For example, the hypothalamus makes GnRH, the pituitary makes Growth Hormone, and the thyroid produces thyroxine.

Exam Tip: Memorizing the primary hormones produced by each gland is crucial. Focus on understanding the main function of each hormone in simple terms.

 

Question 4. Fill in the blanks:

Answer:
The correct matches for hormones and their target glands are:
(a) Hypothalamic hormones - Pituitary gland
(b) Thyrotrophin (TSH) - Thyroid gland
(c) Corticotrophin (ACTH) - Adrenal cortex
(d) Gonadotrophins (LH, FSH) - Posterior Pituitary gland
(e) Melanotrophin (MSH) - Pineal gland
In simple words: This table shows which gland each hormone acts on. For example, hypothalamic hormones affect the pituitary, and TSH affects the thyroid.

Exam Tip: Understanding the target glands for each hormone is key to grasping the endocrine system's regulatory mechanisms. This is a common question format to test knowledge of hormone pathways.

 

Question 5. Write short notes on the functions of the following hormones:
1. Parathyroid hormone (PTH)
2. Thyroid hormones
3. Thymosins
4. Androgens
5. Estrogens
6. Insulin and Glucagon
Answer:
1. Parathyroid hormone (PTH)-Functions:
(1) This hormone boosts the level of calcium ions in the blood plasma because it moves a lot of calcium from bones into the blood plasma and decreases the amount of calcium passed out in the urine.
(2) A low level of calcium in the blood, regulated by a feedback control system, boosts parathormone levels, which then brings the normal \( \text{Ca}^{2+} \) concentration back in the plasma.
(3) The hormone decreases the level of phosphate concentration in the blood plasma and increases the phosphate concentration in the urine.
(4) It controls how calcium and phosphorus are used in the blood. A good balance of calcium and phosphorus is important for strong bones and teeth, for muscle tone, and for proper nerve activity. Calcium is essential for blood clotting and for many enzyme actions. The hormone plays a vital role in maintaining the body's internal balance, supporting activities such as membrane permeability, heart function, and reproduction. Parathormone, when combined with vitamin D, increases active absorption.
2. Thyroid hormones Functions:
(1) These hormones raise the body's metabolic rate, which causes a rise in heat production. They help maintain the basal metabolic rate (BMR). They quicken the process of releasing energy through oxidation. This impact is known as a calorigenic effect.
(2) Thyroid hormones encourage the absorption and use of glucose in cells, and also the breakdown of glycogen in the liver and muscles.
(3) These hormones increase the creation of proteins, RNA, and lipids. They also cause the breakdown of lipids (catabolism).
(4) These hormones support the growth of body tissues and encourage physical growth and the advancement of mental skills.
(5) Thyroxin manages body weight, speeds up the heart rate, and leads to greater use of oxygen and release of \( \text{CO}_2 \). It also manages the operation of the adrenal cortex and gonads.
(6) Thyroxin also influences the body's waste removal processes.
3. Thymosins: Functions:
These hormones regulate the growth of the skeleton, the development of sex glands, and speed up the achievement of sexual maturity. They also boost body immunity, stimulate cell division, and impact body growth.
4. Androgens: Functions:
Androgens regulate the growth, maturing, and functions of male accessory sex organs such as the epididymis, vas deferens, seminal vesicles, prostate gland, and urethra. These hormones encourage muscle growth, the growth of facial and armpit hair, aggressiveness, and a lower voice pitch. Androgens play a significant role in sperm production. They also affect the central nervous system and influence male sexual actions. These hormones help build up (synthesize) proteins and affect how the body uses carbohydrates.
5. Estrogens: Functions:
Estrogens cause many actions, such as encouraging the growth and activities of female secondary sex organs, developing growing ovarian follicles, the appearance of female secondary sex characteristics (like a high-pitched voice), and the growth of mammary glands. Estrogens also manage female sexual behavior.
6. Insulin and Glucagon: Functions:
Insulin is a peptide hormone that plays a major part in regulating glucose balance in the body. Insulin acts mainly on liver cells and fat cells, boosting cellular glucose intake and use. As a result, glucose quickly moves from the blood to liver cells and fat cells, causing lower blood glucose levels (hypoglycemia). Insulin also encourages the change of glucose to glycogen (glycogenesis) in the target cells. The balance of glucose in the blood is kept by both insulin and glucagon working together. Patients with diabetes are effectively treated with insulin therapy. Glucagon is also a peptide hormone and has a key role in keeping normal blood glucose levels. Glucagon mainly acts on liver cells (hepatocytes) and encourages the breakdown of glycogen, leading to higher blood sugar (hyperglycemia). Moreover, this hormone boosts the process of gluconeogenesis, which also helps raise blood sugar. Glucagon decreases how much glucose cells take in and use. Thus, glucagon is a hormone that raises blood glucose levels.
In simple words: PTH helps control calcium levels. Thyroid hormones control metabolism and growth. Thymosins help with immunity and sexual maturity. Androgens are for male development. Estrogens are for female development. Insulin lowers blood sugar, while glucagon raises it, both working together to keep sugar levels balanced.

Exam Tip: For each hormone, remember its primary role (e.g., calcium regulation, metabolism, growth, sex characteristics, blood sugar). When writing short notes, include key functions and any specific effects on body tissues or systems.

 

Question 6. Give examples of:
1. Hyperglycemic hormone and hypoglycemic hormone
2. Hypercalcemic hormone
3. Gonadotrophic hormones
4. Progestational hormone
5. Blood pressure-lowering hormone
6. Androgens and estrogens.
Answer:
1. Hyperglycemic hormone: Glucagon; Hypoglycemic hormone: Insulin
2. Hypercalcemic hormone: Parathyroid hormone (PTH)
3. Gonadotrophic hormones: Luteinizing hormone (LH) and Follicle-stimulating hormone (FSH)
4. Progestational hormone: Progesterone
5. Blood pressure-lowering hormone: Atrial natriuretic factor (ANF)
6. Androgens: Testosterone; Estrogens: Estrogen
In simple words: This question asks for hormones that do specific jobs. Glucagon raises blood sugar, while insulin lowers it. PTH raises blood calcium. LH and FSH help with reproduction. Progesterone prepares the uterus. ANF lowers blood pressure. Testosterone is a male hormone, and estrogen is a female hormone.

Exam Tip: Focus on linking each hormone to its primary effect or category (e.g., blood sugar, calcium, reproduction, blood pressure). This is a direct recall question, so precise answers are important.

 

Question 7. Which hormonal deficiency is responsible for the following:
1. Diabetes mellitus
2. Goiter
3. Cretinism
Answer:
1. Diabetes mellitus: This condition happens due to a lack of insulin secretion.
2. Goiter: This occurs when the thyroid gland is overactive and releases an excessive amount of thyroid hormones.
3. Cretinism: This is caused by an over-secretion of somatotropin from childhood.
In simple words: Diabetes happens when there isn't enough insulin. Goiter is from too much thyroid hormone. Cretinism is from too much somatotropin during childhood.

Exam Tip: Understand whether a condition is caused by a deficiency (too little) or an excess (too much) of a hormone. Also, be clear on which specific hormone is involved for each disorder.

 

Question 8. Briefly mention the mechanism of action of FAH.
Answer: Follicle-stimulating hormone (FSH) encourages the testes in males and ovaries in females to release sperms in males and ova in females. It also causes the release of female sex hormones, like estrogens, in female ovarian follicles.
In simple words: FSH makes male testes produce sperm and female ovaries produce eggs. It also helps ovaries make female hormones like estrogen.

Exam Tip: For hormones, clearly state where they act (target organs) and what specific processes they stimulate or regulate in both males and females if applicable.

 

Question 9. Match the following

Answer:
The correct matches are:
(i) TSH - (b) Thyroid
(ii) PTH - (d) Parathyroid
(iii) GnRH - (a) Hypothalamus
(iv) LH - (c) Pituitary
In simple words: TSH acts on the thyroid. PTH comes from the parathyroid. GnRH is from the hypothalamus. LH is from the pituitary.

Exam Tip: For matching questions, it is helpful to first identify the gland or origin for each hormone or vice-versa, then draw connections to its target or related structure. Accuracy in pairing is essential.