Chemical Coordination and Integration

• Cortisol produces anti-inflammatory reactions and suppresses the immune response.

• Aldosterone acts mainly at the renal tubules and stimulates the reabsorption of $\mathrm{Na}^{+}$and water and excretion of $\mathrm{K}^{+}$and phosphate ions.

• Cholecystokinin (CCK) acts on both pancreas and gall bladder and stimulates the secretion of pancreatic enzymes and bile juice, respectively.

• Progesterone acts on the mammary glands and stimulates the formation of alveoli.

Adenohypophysis of pituitary gland also secrets prolactin.

The two main types of cells in the Islet of Langerhans are called $\alpha$-cells and $\beta$-cells.

The $\alpha$-cells secrete a hormone called glucagon, while the $\beta$-cells secrete insulin.

Glucagon stimulates glycogenolysis while insulin stimulates glycogenesis.

Excess growth hormone → Acromegaly

Luteinizing hormone → Ovulation

Vasopressin → Reabsorption of water and electrolytes in kidneys

Oxytocin → Contraction of uterus during child birth.

The correct matching is [A-IV, B-II, C-I, D-III].

Progesterone is a steroidal hormone produced by the corpus luteum.

Relaxin is a protein hormone secreted by the ovaries, particularly during the later stages of pregnancy.

Melanocyte Stimulating Hormone is a protein hormone released by the pars intermedia.

Catecholamines are amino acid-derived hormones released from the adrenal medulla, often during stress or emergency conditions.

Adrenal medulla secretes two hormones called adrenaline or epinephrine and noradrenaline or norepinephrine (also called emergency hormones).

Both the hormones -

$\bullet$ Cause pupillary dilation (not constriction)

$\bullet$ Stimulate breakdown of glycogen resulting in increased concentration of glucose in blood i.e., cause hyperglycemia.

$\bullet$ Cause piloerection (raising of hair).

$\bullet$ Increase strength of heart contraction i.e. heartbeat.

Neurohypophysis i.e., posterior pituitary (Pars nervosa) stores and releases two hormones called oxytocin and vasopressin (Also called ADH i.e., antidiuretic hormone) which are actually synthesised by hypothalamus and are transported axonally to neurohypophysis. The pars distalis (anterior pituitary) produces follicle stimulating hormone (FSH), adrenocorticotropic hormone (ACTH) and luteinizing hormone (LH).

To match the organs with the hormones they secrete, consider the following associations:

Heart: Produces the hormone Atrial natriuretic factor.

Kidney: Secretes Erythropoietin.

Gastro-intestinal tract: Releases the hormone Secretin.

Adrenal Cortex: Known for secreting Aldosterone.

Each organ is linked to a specific hormone that plays a vital role in various physiological processes within the body. Understanding these relationships is key to comprehending how different systems within the body maintain homeostasis.

Insulin is a peptide hormone, so if taken by mouth:

It passes through the stomach’s acidic environment

Proteolytic enzymes in the GI tract break its peptide bonds

Practically none of the intact hormone reaches the bloodstream

Therefore the correct choice is Option D: It will be digested in the Gastro-Intestinal tract.

Normal cardiac activities of the heart are regulated intrinsically, i.e., auto regulated by specialised muscles (nodal tissue), hence the heart is called myogenic. A special neural centre in the medulla oblongata can moderate the cardiac function through autonomic nervous system.

Sympathetic nervous system can increase the rate of heartbeat, ventricular contraction and thereby cardiac output.

Parasympathetic neural signals decrease the rate of heartbeat, speed of conduction of action potential and thereby the cardiac output. Adrenal medullary hormones can also increase the cardiac output.

To correctly match List-I with List-II, let us consider the primary functions or associations of each hormone:

Epinephrine: Also known as adrenaline, epinephrine is commonly released during stress or emergencies, causing increased heart rate, blood flow to muscles, and hyperglycemia (raised blood glucose levels). Hence, it is often referred to as the "emergency hormone". Therefore, Epinephrine matches with "Emergency hormone".

Thyroxine: This is a hormone produced by the thyroid gland and is primarily responsible for regulating the basal metabolic rate (BMR). Therefore, Thyroxine matches with "Basal metabolic rate".

Oxytocin: A hormone best known for its role in childbirth and lactation, it leads to smooth muscle contraction, particularly in the uterus during labor. Therefore, Oxytocin matches with "Smooth muscle contraction".

Glucagon: This hormone plays an essential role in glucose metabolism, particularly in raising blood glucose levels, leading to hyperglycemia. Therefore, Glucagon matches with "Hyperglycemia".

So, the correct matching is:

(A) Epinephrine - (IV) Emergency hormone

(B) Thyroxine - (III) Basal metabolic rate

(C) Oxytocin - (II) Smooth muscle contraction

(D) Glucagon - (I) Hyperglycemia

The correct answer is:

Option C

A-IV, B-III, C-II, D-I

Let’s analyze each of the statements to identify the wrong ones:

A. Erythropoietin is produced by juxtaglomerular cells of the kidney

This statement is incorrect. Erythropoietin is primarily produced by the interstitial fibroblasts in the kidney, not by the juxtaglomerular cells.

B. Leydig cells produce Androgens

This statement is correct. Leydig cells in the testes produce androgens, such as testosterone.

C. Atrial Natriuretic factor, a peptide hormone, is secreted by the seminiferous tubules of the testes

This statement is incorrect. Atrial Natriuretic factor (ANF) is secreted by the cardiac atria, not by the seminiferous tubules of the testes.

D. Cholecystokinin is produced by the gastrointestinal tract

This statement is correct. Cholecystokinin is a hormone produced by the cells in the mucosal lining of the small intestine.

E. Gastrin acts on the intestinal wall and helps in the production of pepsinogen

This statement is incorrect. Gastrin primarily acts on the stomach lining (gastric mucosa) to stimulate the secretion of gastric acid and pepsinogen, not the intestinal wall.

Based on this analysis, the wrong statements are A, C, and E. Therefore, the most appropriate answer from the given options is:

Option C

C and E only

Steroid hormones are a class of hormones that are derived from cholesterol and are lipophilic (fat-soluble) in nature. They can easily pass through the cell membranes of target cells to bind with intracellular receptors. Common examples of steroid hormones include cortisol, testosterone, and progesterone, each involved in different regulatory functions in the body.

Cortisol (Option A) is a glucocorticoid hormone produced by the adrenal cortex. It is involved in the regulation of metabolism, immune response, and stress response.

Testosterone (Option B) is an androgen hormone primarily produced in the testes in males and in smaller quantities in the ovaries in females. It plays a key role in developing male reproductive tissues and promoting secondary sexual characteristics such as muscle and bone mass, and the growth of body hair.

Progesterone (Option C) is a hormone released by the ovaries and is important in the regulation of menstruation and maintaining the early stages of pregnancy.

Glucagon (Option D) is fundamentally different from the aforementioned hormones. It is a peptide hormone, not a steroid hormone. Glucagon is produced by the alpha cells of the pancreas and works to raise the concentration of glucose in the bloodstream by promoting gluconeogenesis and glycogenolysis in the liver. Unlike steroid hormones, glucagon does not pass through cell membranes but binds to receptors on the cell surface.

Thus, the correct answer to the question is Option D: Glucagon, as it is not a steroid hormone.

Statement Assertion A states that "FSH acts upon ovarian follicles in female and Leydig cells in male." To analyze this, we need to examine the role of FSH (Follicle Stimulating Hormone) in both genders.

In females, FSH indeed acts on ovarian follicles. It stimulates the growth and maturation of these follicles, which is critical for oocyte development and estrogen production. Consequently, FSH plays a fundamental role in the menstrual cycle and fertility in females.

In males, however, FSH acts on the Sertoli cells, not the Leydig cells. The function of FSH in males is to promote spermatogenesis by acting on Sertoli cells in the testes, which support the development of sperm. On the other hand, Leydig cells, influenced by Luteinizing Hormone (LH), are responsible for the production of testosterone, a primary male sex hormone.

Moving on to Reason R, which asserts that "Growing ovarian follicles secrete estrogen in female while interstitial cells secrete androgen in male human being." Both parts of this statement are accurate. In females, the growing ovarian follicles indeed secrete estrogen, pivotal in regulating the female reproductive cycle and secondary sexual characteristics. In males, interstitial cells, another term for Leydig cells, produce androgens, like testosterone, vital for male reproductive functions and characteristics.

Given this, Assertion A is false because its statement about FSH acting on Leydig cells in males is incorrect. However, Reason R is true as it accurately describes hormone secretion by ovarian follicles and Leydig cells in females and males, respectively.

Therefore, the correct answer is:

Option D: A is false but R is true.

To solve the matching question, we need to correctly link each disease (List-I) with their corresponding characteristics (List-II). Here is the breakdown of each disease and its effects:

Exophthalmic goiter: Also known as Graves' disease, this is an autoimmune disorder that involves an overactive thyroid (hyperthyroidism) and is characterized by symptoms such as protruding eyeballs. Therefore, this matches with "Hyper secretion of thyroid hormone & protruding eye balls." - from List II (III).

Acromegaly: This condition is caused by excessive secretion of growth hormone, usually from a benign tumor in the pituitary gland, leading to enlarged features (bones, especially in the hands, feet, and face). Thus, it corresponds with "Excessive secretion of growth hormone." - from List II (IV).

Cushing's syndrome: This syndrome is the result of prolonged exposure to high levels of the hormone cortisol. It features symptoms including obesity majorly centered around the abdomen and upper back, moon face, and hyperglycemia. Therefore, it fits "Excess secretion of cortisol, moon face & hyperglycemia." - from List II (I).

Cretinism: This is a condition arising from the deficiency of thyroid hormone in childhood, which causes impaired neurological function, stunted physical growth, and possibly other symptoms. It matches with "Hypo-secretion of thyroid hormone and stunted growth." - from List II (II).

Now, compare these with the available options:

• Option A - A-I, B-III, C-II, D-IV - Incorrect because the descriptions do not match correctly.
• Option B - A-IV, B-II, C-I, D-III - Incorrect because the descriptions do not match correctly.
• Option C - A-III, B-IV, C-II, D-I - Incorrect because of an incorrect assignment for C and D.
• Option D - A-III, B-IV, C-I, D-II - Correct, as all labels are correctly matched according to the disease and characteristic explanations provided above.

Therefore, the correct answer is Option D.

The incorrect statement is :

Option A : Mature insulin molecule consists of three polypeptide chains-A, B, and C.

The mature insulin molecule actually consists of only two polypeptide chains, A and B, which are linked by disulfide bridges. The C-peptide, or chain C, is present in the proinsulin molecule but is removed during the maturation process to produce the active form of insulin. Therefore, statements B, C, and D are correct.

Let's analyze each statement :

(A) Thyrocalcitonin (TCT) regulates the blood calcium level.

• This is correct. Thyrocalcitonin (or calcitonin) is a hormone produced by the thyroid gland that helps regulate levels of calcium and phosphorus in the blood.

(B) In males, FSH and androgens regulate spermatogenesis.

• This is correct. FSH (Follicle Stimulating Hormone) stimulates the Sertoli cells to support spermatogenesis, and androgens (like testosterone) stimulate the development of male secondary sexual characteristics and are also necessary for spermatogenesis.

(C) Hyperthyroidism can lead to goitre.

• This is incorrect. Goitre is typically caused by iodine deficiency or thyroid inflammation, not by hyperthyroidism. Hyperthyroidism is a condition where the thyroid gland is overactive and produces too much thyroid hormone.

(D) Glucocorticoids are secreted in Adrenal Medulla.

• This is incorrect. Glucocorticoids, such as cortisol, are produced in the adrenal cortex, not the adrenal medulla.

(E) Parathyroid hormone is regulated by circulating levels of sodium ions.

• This is incorrect. Parathyroid hormone is regulated by circulating levels of calcium ions, not sodium ions.

Therefore, the correct answer is :

Option B - (A) and (B) only

Option A is correct : Statement I is correct but Statement II is false.

Statement I : Parathyroid hormone (PTH) indeed acts on bones and stimulates the process of bone resorption. It also acts on the kidneys to stimulate reabsorption of calcium, and on the intestines (indirectly via vitamin D activation) to enhance absorption of dietary calcium. All these actions increase the blood calcium levels.

Statement II : Parathyroid hormone and calcitonin (produced by the thyroid gland, not "Thyrocalcitonin") are key regulators of calcium homeostasis in the body. However, they do not play a significant role in carbohydrate metabolism. The key hormones involved in carbohydrate metabolism are insulin and glucagon, both produced by the pancreas. Therefore, Statement II is false.

Option (B) is the correct answer because thyroid hormones play an important role in the regulation of basal metabolic rate, maintenance of water and electrolyte balance and support the process of RBCs formation, whereas this hormone is not involved in regulating normal rhythm of sleep-wake cycle and development of immune system.

Assertion (A) is correct because FSH, or follicle-stimulating hormone, is a peptide hormone that does not enter the target cell. Instead, it interacts with membrane-bound receptors on the surface of the target cell. This is a common feature of peptide hormones, as they are too large and hydrophilic to pass through the cell membrane.

Reason (R) is also correct. When FSH binds to its receptor, it triggers a cascade of intracellular events, including the production of second messengers like cyclic AMP (cAMP). The second messengers then go on to activate various biochemical and physiological responses within the target cell, such as cell growth and hormone production. This is a typical process for signal transduction initiated by the binding of a hormone to its cell surface receptor.

However, (R) is not the correct explanation of (A) because it doesn't directly address why FSH doesn't enter the target cell. The reason FSH does not enter the target cell is that it is a peptide hormone, which cannot cross the cell membrane. Instead, it interacts with cell surface receptors to initiate a signaling cascade. The generation of second messengers, like cAMP, is a part of the signaling process that takes place after FSH binds to its receptor, but it is not the reason why FSH doesn't enter the cell.

Option (b) is the correct answer because parathyroid hormone is a hypercalcemic hormone i.e., it increases the blood calcium levels. It also increases the absorption of calcium from digested food. Glucocorticoids regulate the carbohydrate metabolism.

Option (c) is not the answer because parathyroid hormone stimulates the process of bone resorption.

Option (a) and (d) are not the answers because reabsorption of Ca²⁺ by renal tubules is a function of PTH.

Erythropoietin is a hormone that plays a crucial role in the production of red blood cells (RBCs), also known as erythropoiesis. This hormone is primarily produced in response to hypoxia, which is a condition characterized by low oxygen levels in the blood. It functions by stimulating the bone marrow to increase the production of RBCs, thereby enhancing the blood's oxygen-carrying capacity.

To address the specific options provided:

Option A: Juxtaglomerular cells of the kidney

This is the correct answer. Juxtaglomerular cells, which are located in the kidneys, are primarily responsible for the production and secretion of erythropoietin. When the kidneys sense a decrease in oxygen levels in the blood, the juxtaglomerular cells respond by releasing erythropoietin, which then travels to the bone marrow to stimulate RBC production.

Option B: Alpha cells of pancreas

This is incorrect. The alpha cells of the pancreas are responsible for producing the hormone glucagon, which plays a key role in blood glucose regulation by promoting the release of glucose from stored glycogen in the liver.

Option C: The cells of rostral adenohypophysis

This is incorrect. The rostral adenohypophysis refers to the anterior part of the pituitary gland, which secretes various hormones, but not erythropoietin. The anterior pituitary's hormones include growth hormone, prolactin, and adrenocorticotropic hormone (ACTH), among others.

Option D: The cells of bone marrow

This is incorrect. While the bone marrow is the site where RBCs are produced, it does not produce erythropoietin. Instead, it is the target of erythropoietin, which stimulates the bone marrow cells to proliferate and differentiate into red blood cells.

Therefore, the correct answer is:

Option A: Juxtaglomerular cells of the kidney