Chemical Coordination and Integration

Topic: Pancreatic Hormones; Subtopic: Insulin Biosynthesis

Keyword Definitions:

• Insulin: Hormone produced by pancreatic β-cells that regulates blood glucose levels.

• Pro-hormone: Inactive precursor of a hormone that requires processing to become active.

• C-peptide: Connecting peptide linking A-chain and B-chain in proinsulin, removed during maturation.

• A-peptide/B-peptide chain: Functional polypeptide chains of insulin after C-peptide removal.

• β-cells: Pancreatic cells located in islets of Langerhans that synthesize insulin.

• Proinsulin: Inactive form of insulin containing A-chain, B-chain, and C-peptide.

• Mature insulin: Active hormone consisting of A-chain and B-chain linked by disulfide bonds.

• Processing: Cleavage of C-peptide from proinsulin to generate biologically active insulin.

Lead Question – 2022 (Abroad)
Given below are two statements: one is labelled as Assertion (A) and the other as Reason (R).
Assertion (A): In human beings, insulin is synthesized as a pro-hormone which needs to be processed before it becomes fully mature and functional.
Reason (R): The extra stretch of C-peptide is to be removed from A-peptide and B-peptide chain of insulin.
In the light of the above statements, choose the most appropriate answer from the options below:
1. (A) is correct but (R) is not correct
2. (A) is not correct but (R) is correct
3. Both (A) and (R) are correct and (R) is the correct explanation of (A)
4. Both (A) and (R) are correct but (R) is not the correct explanation of (A)

Explanation:
Correct answer is option 3. Insulin is synthesized in pancreatic β-cells as an inactive precursor called proinsulin, consisting of the A-chain, B-chain, and C-peptide. During maturation, the C-peptide is enzymatically cleaved, leaving the A and B chains linked by disulfide bonds to form biologically active insulin. This processing ensures proper folding and functionality of insulin, while the C-peptide has no hormonal activity but is released in equimolar amounts. The reason accurately explains the assertion, as removal of C-peptide is essential for insulin to become fully mature and capable of regulating blood glucose levels effectively.

1. What is the role of C-peptide in insulin biosynthesis?
1. It is the active part of insulin
2. It stabilizes A and B chains during folding
3. It acts as a hormone itself
4. It remains attached in mature insulin
Explanation: Correct answer is It stabilizes A and B chains during folding. C-peptide is part of proinsulin and ensures proper folding of A and B chains via disulfide bond formation. It is cleaved during maturation to form active insulin. Though released in circulation, it has minimal direct hormonal activity, serving mainly as a marker for endogenous insulin production.

2. Proinsulin consists of:
1. Only A and B chains
2. A-chain, B-chain, and C-peptide
3. C-peptide only
4. Single polypeptide chain without cleavage sites
Explanation: Correct answer is A-chain, B-chain, and C-peptide. Proinsulin is a single-chain precursor containing A-chain, B-chain, and the connecting C-peptide. The C-peptide is cleaved enzymatically to generate mature insulin consisting of two chains linked by disulfide bonds. This precursor ensures correct folding and proper structural formation of active insulin in β-cells.

3. Which cells synthesize insulin in humans?
1. α-cells of pancreas
2. β-cells of pancreas
3. δ-cells of pancreas
4. Exocrine acinar cells
Explanation: Correct answer is β-cells of pancreas. β-cells in the islets of Langerhans produce proinsulin, which is processed into active insulin. α-cells secrete glucagon, δ-cells secrete somatostatin, and acinar cells are exocrine, producing digestive enzymes. β-cells are central to glucose homeostasis through regulated insulin secretion.

4. Mature insulin consists of:
1. Only A-chain
2. Only B-chain
3. A-chain and B-chain linked by disulfide bonds
4. A-chain, B-chain, and C-peptide
Explanation: Correct answer is A-chain and B-chain linked by disulfide bonds. Upon cleavage of C-peptide from proinsulin, the A and B chains are joined by disulfide bridges to form active insulin. This structure is critical for receptor binding and glucose regulation. C-peptide is removed but secreted separately in equimolar amounts.

5. Removal of C-peptide from proinsulin is necessary because:
1. C-peptide is toxic
2. Only A and B chains are biologically active
3. It prevents folding of insulin
4. It reduces insulin solubility
Explanation: Correct answer is Only A and B chains are biologically active. C-peptide serves as a connector during folding but has no direct hormonal effect. Its removal produces mature insulin capable of binding to insulin receptors. Proper cleavage ensures functional hormone secretion and regulation of blood glucose.

6. The term “pro-hormone” refers to:
1. Active hormone
2. Inactive precursor requiring processing
3. Hormone degraded in liver
4. Hormone bound to carrier protein
Explanation: Correct answer is Inactive precursor requiring processing. Proinsulin is a pro-hormone, inactive until enzymatic removal of C-peptide. Pro-hormones ensure correct folding, storage, and regulated activation of hormones. This mechanism prevents premature activity and maintains homeostasis.

7. Assertion-Reason:
Assertion (A): Insulin is synthesized as a pro-hormone.
Reason (R): Proinsulin contains C-peptide which must be removed to activate insulin.
1. Both A and R are true, R is correct explanation of A
2. Both A and R are true, R is not correct explanation
3. A is true, R is false
4. A is false, R is true
Explanation: Correct answer is option 1. Insulin is synthesized as proinsulin in β-cells. The C-peptide connects the A and B chains and is removed enzymatically to produce mature, biologically active insulin. The reason accurately explains the assertion, linking pro-hormone processing to activation of insulin.

8. Matching Type:
Match List-I (Molecule) with List-II (Function):
A. Proinsulin – (i) Inactive precursor
B. C-peptide – (ii) Connector peptide during folding
C. Mature insulin – (iii) Regulates blood glucose
D. β-cells – (iv) Site of synthesis
1. A–i, B–ii, C–iii, D–iv
2. A–ii, B–i, C–iv, D–iii
3. A–iii, B–ii, C–i, D–iv
4. A–iv, B–iii, C–ii, D–i
Explanation: Correct answer is option 1. Proinsulin is the inactive precursor (A–i), C-peptide stabilizes A and B chains (B–ii), mature insulin regulates blood glucose (C–iii), and β-cells are the synthesis site (D–iv). This illustrates biosynthesis, processing, and functional role of insulin and associated peptides.

9. Fill in the Blanks:
The __________ is cleaved from proinsulin to produce active insulin.
1. A-chain
2. B-chain
3. C-peptide
4. β-cell nucleus
Explanation: Correct answer is C-peptide. During insulin maturation, the connecting C-peptide is enzymatically removed, leaving A and B chains linked by disulfide bonds. This cleavage converts proinsulin to biologically active insulin, enabling glucose regulation. The C-peptide is secreted in equimolar amounts but has no direct hormonal function.

10. Choose the Correct Statements:
Statement I: Proinsulin contains A-chain, B-chain, and C-peptide.
Statement II: Mature insulin contains all three components including C-peptide.
1. Statement I correct, Statement II incorrect
2. Statement I incorrect, Statement II correct
3. Both statements correct
4. Both statements incorrect
Explanation: Correct answer is Statement I correct, Statement II incorrect. Proinsulin has A, B chains, and C-peptide, while mature insulin only contains A and B chains linked by disulfide bonds. Removal of C-peptide is essential for activation. This illustrates the processing step critical in hormone maturation and function.

Topic: Hormones of Digestive System; Subtopic: Intestinal Hormones

Keyword Definitions:

• Enterokinin: An intestinal hormone secreted by the small intestine that stimulates pancreatic secretion rich in bicarbonate ions.

• Pancreas: A glandular organ that secretes digestive enzymes and bicarbonate-rich fluid to neutralize stomach acid.

• Bicarbonate ions (HCO₃⁻): Ions that neutralize acidic chyme entering the small intestine from the stomach.

• Cholecystokinin (CCK): A hormone that stimulates gall bladder contraction and pancreatic enzyme secretion.

Lead Question – 2022 (Abroad)
An intestinal hormone that stimulates the pancreas to release a watery secretion that is rich in bicarbonate ions:
1. Cholecystokinin
2. Gastric Inhibitory Peptide
3. Enterokinin
4. Secretion

Explanation:
The correct answer is Enterokinin. This hormone, secreted by the mucosa of the small intestine, stimulates the pancreas to release a watery fluid rich in bicarbonate ions, which neutralizes acidic chyme entering from the stomach. It is essential for maintaining optimal pH in the duodenum for enzyme activity and digestion efficiency.

1. Which hormone stimulates pancreatic enzyme secretion?
1. Secretin
2. Enterokinin
3. Gastrin
4. Insulin
Explanation: Enterokinin stimulates the pancreas to secrete bicarbonate-rich watery fluid, while other hormones like gastrin primarily regulate stomach acid and secretin mainly stimulates bicarbonate secretion from the pancreas. Its activity ensures neutralization of chyme for proper enzymatic digestion in the small intestine.

2. Which ion is abundant in pancreatic secretion stimulated by enterokinin?
1. Chloride
2. Bicarbonate (HCO₃⁻)
3. Sodium
4. Potassium
Explanation: Enterokinin-stimulated pancreatic secretion is rich in bicarbonate ions (HCO₃⁻). These ions neutralize acidic chyme from the stomach, providing an optimal pH for pancreatic enzymes like amylase, lipase, and proteases, which function best in slightly alkaline conditions, ensuring efficient digestion and nutrient absorption.

3. Enterokinin is secreted by which part of the digestive system?
1. Stomach
2. Small intestine
3. Large intestine
4. Pancreas
Explanation: Enterokinin is secreted by the epithelial cells of the small intestine, mainly in the duodenum and jejunum. Its secretion is triggered by the presence of chyme, and it signals the pancreas to release a bicarbonate-rich secretion, neutralizing acidity and creating suitable conditions for enzymatic digestion.

4. Which hormone triggers gall bladder contraction along with pancreatic enzyme release?
1. Enterokinin
2. Secretin
3. Cholecystokinin (CCK)
4. Gastric Inhibitory Peptide
Explanation: Cholecystokinin (CCK) stimulates gall bladder contraction and release of bile, along with pancreatic enzyme secretion. It complements enterokinin, which primarily stimulates bicarbonate-rich fluid from the pancreas, aiding in fat digestion and overall digestive efficiency in the duodenum.

5. Bicarbonate-rich pancreatic secretion helps in:
1. Protein breakdown in the stomach
2. Neutralizing acidic chyme
3. Stimulating gastric acid
4. Absorbing water in colon
Explanation: The bicarbonate-rich secretion stimulated by enterokinin neutralizes acidic chyme entering the small intestine from the stomach. This neutralization prevents mucosal damage, provides optimal pH for pancreatic enzyme activity, and ensures efficient digestion of carbohydrates, proteins, and fats.

6. Which of the following is not secreted by the small intestine?
1. Enterokinin
2. Secretin
3. Gastrin
4. Cholecystokinin (CCK)
Explanation: Gastrin is primarily secreted by the stomach to stimulate acid production. Other hormones like enterokinin, secretin, and CCK are secreted by the small intestine to regulate pancreatic secretion, bile release, and neutralization of chyme, ensuring effective digestion and absorption.

7. Assertion-Reason Type:
Assertion (A): Enterokinin stimulates bicarbonate secretion from the pancreas.
Reason (R): Neutralization of acidic chyme is required for optimal enzymatic digestion.
1. Both A and R are true, and R is the correct explanation of A.
2. Both A and R are true, but R is not the correct explanation of A.
3. A is true, but R is false.
4. A is false, but R is true.
Explanation: The correct answer is option 1. Enterokinin stimulates the pancreas to release bicarbonate-rich fluid. This action neutralizes acidic chyme from the stomach, creating an alkaline environment necessary for digestive enzymes to function efficiently in the duodenum.

8. Matching Type:
Match the hormone with its function:
A. Enterokinin – (i) Stimulates pancreatic bicarbonate secretion
B. Secretin – (ii) Stimulates water and bicarbonate secretion
C. Cholecystokinin – (iii) Stimulates bile release
D. Gastrin – (iv) Stimulates gastric acid secretion
1. A–i, B–ii, C–iii, D–iv
2. A–ii, B–i, C–iv, D–iii
3. A–iii, B–i, C–ii, D–iv
4. A–iv, B–ii, C–i, D–iii
Explanation: The correct answer is option 1. Enterokinin stimulates pancreatic bicarbonate secretion, secretin promotes watery alkaline fluid, CCK stimulates bile and pancreatic enzyme release, and gastrin increases gastric acid secretion, coordinating digestion in the gastrointestinal tract efficiently.

9. Fill in the Blanks:
_________ is secreted by the small intestine to neutralize acidic chyme.
1. Cholecystokinin
2. Enterokinin
3. Secretin
4. Gastrin
Explanation: The blank is filled with Enterokinin. It stimulates the pancreas to release a watery, bicarbonate-rich secretion, which neutralizes the acidic chyme entering from the stomach, providing an optimal pH for enzymatic activity in the duodenum and facilitating efficient nutrient digestion.

10. Choose the Correct Statements:
Statement I: Enterokinin stimulates the pancreas to secrete bicarbonate-rich fluid.
Statement II: Bicarbonate neutralizes chyme, aiding in digestion.
1. Both statements are correct
2. Both statements are incorrect
3. Statement I is correct, Statement II is incorrect
4. Statement I is incorrect, Statement II is correct
Explanation: The correct answer is option 1. Enterokinin stimulates the pancreas to secrete a bicarbonate-rich fluid. This fluid neutralizes acidic chyme from the stomach, maintaining an optimal pH for enzyme activity and efficient digestion, ensuring proper nutrient breakdown and absorption in the small intestine.

Topic: Endocrine Glands and Hormones; Subtopic: Pineal Gland and Biological Rhythms

Keyword Definitions:

• Melatonin: A hormone secreted by the pineal gland that regulates sleep-wake cycles and circadian rhythms.

• Pineal Gland: A small, pea-shaped gland in the brain responsible for melatonin secretion.

• Biological Rhythm: Natural cycles of physiological activity, including sleep and wakefulness.

• Circadian Rhythm: The 24-hour internal clock that regulates physiological and behavioral patterns.

Lead Question – 2022 (Abroad)
Normal sleep-wake cycle in a human body is maintained by the secretion of:
1. Thyroid gland
2. Thymus gland
3. Pineal gland
4. Pituitary gland

Explanation:
The pineal gland secretes melatonin, a hormone that regulates the body’s circadian rhythm and sleep-wake cycle. Its secretion increases in darkness and decreases in light, signaling the brain to rest or awaken. It plays a vital role in maintaining biological clock functions and seasonal reproduction cycles in animals.

1. Which hormone controls the 24-hour body rhythm?
1. Insulin
2. Melatonin
3. Adrenaline
4. Thyroxine
Explanation: The hormone melatonin, produced by the pineal gland, regulates circadian rhythms that control sleep, wakefulness, and other daily cycles. Its levels rise at night and fall during the day, aligning the body’s internal clock with environmental light-dark changes for optimal physiological balance.

2. Which part of the brain regulates pineal gland activity?
1. Cerebellum
2. Hypothalamus
3. Thalamus
4. Cerebrum
Explanation: The hypothalamus controls pineal gland activity by interpreting light and dark signals from the eyes. It sends neural impulses to the pineal gland to regulate melatonin secretion, maintaining circadian rhythm and influencing sleep cycles, hormone release, and body temperature regulation.

3. Melatonin secretion is highest during:
1. Daytime
2. Nighttime
3. Evening
4. Morning
Explanation: Melatonin secretion peaks during the night and drops during daylight. Darkness stimulates pineal gland activity, signaling the body to prepare for sleep. This rhythmic hormone release synchronizes internal biological clocks with external environmental cues such as light and darkness.

4. Which of the following is not an endocrine gland?
1. Pineal gland
2. Sweat gland
3. Pituitary gland
4. Adrenal gland
Explanation: The sweat gland is an exocrine gland because it releases its secretion through ducts onto the skin surface. In contrast, endocrine glands like the pineal, pituitary, and adrenal glands release hormones directly into the bloodstream to regulate various body functions.

5. Which hormone influences reproduction and body temperature along with sleep?
1. Cortisol
2. Melatonin
3. Insulin
4. Progesterone
Explanation: Melatonin affects reproductive hormones and thermoregulation in addition to controlling sleep. High melatonin levels inhibit reproductive activity in some animals during shorter days, aligning breeding cycles with favorable conditions, showing its impact beyond sleep regulation.

6. The pineal gland is located in which part of the brain?
1. Cerebellum
2. Epithalamus
3. Medulla oblongata
4. Hypothalamus
Explanation: The pineal gland lies within the epithalamus, near the brain’s center, between the two hemispheres. Despite its small size, it plays an important role in endocrine regulation by secreting melatonin, thus maintaining biological rhythms and influencing seasonal behaviors.

7. Assertion-Reason Type:
Assertion (A): Pineal gland controls the sleep-wake cycle.
Reason (R): Melatonin secretion is maximum during the day.
1. Both A and R are true, and R is the correct explanation of A.
2. Both A and R are true, but R is not the correct explanation of A.
3. A is true, but R is false.
4. A is false, but R is true.
Explanation: The correct answer is option 3. The pineal gland indeed controls the sleep-wake cycle through melatonin secretion, but melatonin levels are maximum during the night, not the day. Thus, the reason is incorrect, though the assertion remains true.

8. Matching Type:
Match the following glands with their hormones:
A. Pineal gland – (i) Melatonin
B. Adrenal gland – (ii) Cortisol
C. Thyroid gland – (iii) Thyroxine
D. Pancreas – (iv) Insulin
1. A–i, B–ii, C–iii, D–iv
2. A–iv, B–iii, C–ii, D–i
3. A–ii, B–i, C–iv, D–iii
4. A–iii, B–iv, C–i, D–ii
Explanation: The correct match is A–i, B–ii, C–iii, D–iv. Each gland secretes a specific hormone: pineal gland secretes melatonin, adrenal gland secretes cortisol, thyroid gland secretes thyroxine, and pancreas secretes insulin, each having vital roles in homeostasis and metabolism regulation.

9. Fill in the Blanks:
The pineal gland secretes __________ that helps regulate the circadian rhythm.
1. Thyroxine
2. Melatonin
3. Insulin
4. Adrenaline
Explanation: The blank is filled with melatonin. This hormone maintains the circadian rhythm, aligning physiological functions like sleep, metabolism, and hormonal balance with day-night cycles. Its secretion rises in darkness, inducing sleep and synchronizing internal biological clocks to external light conditions.

10. Choose the Correct Statements:
Statement I: Melatonin levels are high during daytime.
Statement II: Pineal gland is an endocrine gland located in the epithalamus.
1. Both statements are correct.
2. Both statements are incorrect.
3. Statement I is incorrect, but Statement II is correct.
4. Statement I is correct, but Statement II is incorrect.
Explanation: The correct answer is option 3. Melatonin levels are low during the day and rise at night. The pineal gland, located in the epithalamus, functions as an endocrine gland controlling sleep cycles, seasonal rhythms, and hormone regulation.

Topic: Endocrinology; Subtopic: Pregnancy Hormones

Keyword Definitions:

• Relaxin: Hormone produced during pregnancy that relaxes ligaments and softens the cervix to aid childbirth.

• Oxytocin: Hormone released by posterior pituitary that stimulates uterine contractions and milk ejection, present in both sexes.

• hCG (Human Chorionic Gonadotropin): Hormone secreted by trophoblast cells during pregnancy, maintaining corpus luteum function and progesterone secretion.

• hPL (Human Placental Lactogen): Placental hormone promoting mammary gland growth and modulating maternal metabolism for fetal nutrition.

• Progesterone: Steroid hormone secreted by corpus luteum and placenta, maintains endometrial lining and inhibits uterine contractions during pregnancy.

• Corpus Luteum: Temporary endocrine structure in ovary producing progesterone after ovulation.

• Placenta: Organ connecting mother and fetus, responsible for nutrient and hormone exchange.

• Endocrinology: Study of hormones, their secretion, and physiological roles.

• Gestation: Period of fetal development in the uterus from conception to birth.

• Fetal Development: Growth and differentiation of the embryo and fetus in utero.

• Maternal Adaptation: Physiological changes in the mother to support pregnancy.

Lead Question - 2022 (Abroad)

Which of the following hormones are secreted in women only during pregnancy?

1. Relaxin

2. Oxytocin

3. hCG

4. hPL

5. Progesterone

Choose the most appropriate answer from the options given below:

1. (c), (d) and (e) only

2. (b) and (e) only

3. (b), (c) and (d) only

4. (a), (c) and (d) only

Explanation: The hormones secreted only during pregnancy include hCG, hPL, and Progesterone. hCG maintains corpus luteum function in early gestation, progesterone sustains endometrial lining and prevents contractions, and hPL modulates maternal metabolism and mammary development. Relaxin is also secreted in pregnancy, but primarily near parturition. Oxytocin is present in both sexes and is not exclusive to pregnancy. These pregnancy-specific hormones coordinate maternal adaptation, fetal development, and preparation for parturition. Correct answer is option 1 (c), (d) and (e) only.

1. SINGLE CORRECT ANSWER MCQ

Which hormone is primarily responsible for maintaining the endometrium during pregnancy?

1. Relaxin

2. Progesterone

3. Oxytocin

4. hPL

Explanation: Progesterone is the key hormone maintaining the endometrial lining during pregnancy. It is secreted initially by the corpus luteum and later by the placenta. Progesterone prevents uterine contractions, supports embryo implantation, and prepares the maternal system for fetal development. Relaxin softens ligaments, hPL aids metabolism, and oxytocin stimulates contractions. Therefore, progesterone is the primary hormone for endometrial maintenance. Correct answer: 2

2. SINGLE CORRECT ANSWER MCQ

Which hormone is secreted by trophoblast cells during early pregnancy?

1. Oxytocin

2. hCG

3. Relaxin

4. Progesterone

Explanation: Human Chorionic Gonadotropin (hCG) is secreted by trophoblast cells of the embryo during early pregnancy. It maintains the corpus luteum and ensures continued progesterone secretion. This hormone is essential for establishing pregnancy and is detected in pregnancy tests. Oxytocin, relaxin, and progesterone play different roles. Understanding hCG secretion is critical for early pregnancy physiology and monitoring gestational health. Correct answer: 2

3. SINGLE CORRECT ANSWER MCQ

Which hormone aids mammary gland growth and modulates maternal metabolism during pregnancy?

1. hPL

2. Oxytocin

3. Progesterone

4. Relaxin

Explanation: Human Placental Lactogen (hPL) is secreted by the placenta and promotes mammary gland development and maternal metabolic adaptation for fetal nutrition. It ensures glucose and lipid availability for fetal growth. Oxytocin controls contractions, progesterone maintains endometrium, and relaxin softens ligaments. hPL’s role is crucial for preparing the maternal body for lactation and supporting fetal energy needs. Correct answer: 1

4. SINGLE CORRECT ANSWER MCQ

Relaxin primarily functions in pregnancy to:

1. Stimulate uterine contractions

2. Soften ligaments and cervix

3. Maintain endometrium

4. Promote fetal growth

Explanation: Relaxin is secreted mainly by the corpus luteum and placenta during late pregnancy. Its main function is to relax pelvic ligaments and soften the cervix, facilitating childbirth. It does not maintain the endometrium, stimulate contractions, or directly promote fetal growth. Relaxin, combined with other pregnancy hormones, ensures proper maternal adaptation for labor. Understanding relaxin’s specific role helps differentiate pregnancy-specific hormonal functions. Correct answer: 2

5. SINGLE CORRECT ANSWER MCQ

Which hormone is not exclusive to pregnancy and is present in both sexes?

1. hCG

2. Oxytocin

3. hPL

4. Relaxin

Explanation: Oxytocin is produced by the posterior pituitary in both sexes and regulates uterine contractions in women and social bonding in both genders. It is not exclusive to pregnancy. In contrast, hCG, hPL, and relaxin are secreted specifically during pregnancy. Understanding this distinction is important in endocrinology, as it separates general pituitary hormones from pregnancy-specific placental hormones. Correct answer: 2

6. SINGLE CORRECT ANSWER MCQ

Which hormone ensures corpus luteum maintenance in early pregnancy?

1. Progesterone

2. hCG

3. Oxytocin

4. Relaxin

Explanation: hCG secreted by trophoblast cells maintains the corpus luteum during early pregnancy, ensuring continuous progesterone production to support the endometrium and prevent miscarriage. Progesterone alone cannot maintain the corpus luteum without hCG signaling. Oxytocin and relaxin perform different roles unrelated to corpus luteum maintenance. Recognizing hCG’s critical role is essential for understanding early pregnancy physiology. Correct answer: 2

7. ASSERTION-REASON MCQ

Assertion (A): hPL is secreted only during pregnancy.

Reason (R): hPL promotes maternal metabolic adaptations and mammary development for fetal support.

1. Both A and R are true and R explains A

2. Both A and R are true but R does not explain A

3. A is true but R is false

4. A is false but R is true

Explanation: Human Placental Lactogen (hPL) is secreted by the placenta exclusively during pregnancy. It modulates maternal metabolism, ensures nutrient supply to the fetus, and promotes mammary gland growth. Both Assertion and Reason are true, and the Reason correctly explains why hPL is pregnancy-specific. This hormone is a critical component of maternal adaptation, ensuring adequate fetal growth and preparation for lactation. Correct answer: 1

8. MATCHING TYPE MCQ

Match the hormones with their primary pregnancy function:

Column A:

1. hCG

2. Progesterone

3. hPL

4. Relaxin

Column B:

1. Maintains corpus luteum

2. Maintains endometrium

3. Maternal metabolic adaptation and mammary growth

4. Softens ligaments and cervix

Explanation: Correct matching: hCG → Maintains corpus luteum, Progesterone → Maintains endometrium, hPL → Maternal metabolism and mammary growth, Relaxin → Softens ligaments and cervix. Each hormone plays a distinct role in pregnancy, ensuring maternal adaptation, fetal development, and preparation for parturition. Understanding their functions is critical for clinical and physiological studies. Answer: hCG-1, Progesterone-2, hPL-3, Relaxin-4

9. FILL IN THE BLANKS / COMPLETION MCQ

The hormone secreted by the placenta that prepares maternal metabolism for fetal nutrition is _______.

1. Progesterone

2. hPL

3. Relaxin

4. Oxytocin

Explanation: Human Placental Lactogen (hPL) is secreted by the placenta during pregnancy. It ensures maternal metabolic adaptations, such as increased glucose and lipid availability, to support fetal growth. Additionally, hPL promotes mammary gland development for lactation. Progesterone maintains endometrium, relaxin softens ligaments, and oxytocin stimulates contractions. Understanding hPL’s role is vital for studying endocrine regulation and maternal-fetal physiology. Correct answer: 2

10. CHOOSE THE CORRECT STATEMENTS MCQ

Statement I: hCG, hPL, and Progesterone are secreted only during pregnancy.
Statement II: Oxytocin is exclusive to pregnant women.

1. Only Statement I is correct

2. Only Statement II is correct

3. Both Statements I and II are correct

4. Both Statements I and II are incorrect

Explanation: hCG, hPL, and progesterone are pregnancy-specific hormones, secreted only during gestation, coordinating maternal adaptation and fetal development. Oxytocin is present in both sexes and is not exclusive to pregnancy, performing roles in social bonding and labor. Therefore, only Statement I is correct. Recognizing pregnancy-specific versus general hormones is essential in endocrinology, clinical assessments, and understanding maternal-fetal physiology. Correct answer: 1

Topic: Endocrine Regulation of Blood Pressure; Subtopic: Hormonal Control of Cardiovascular System

Keyword Definitions:

• Antidiuretic Hormone (ADH): Hormone secreted by posterior pituitary that increases water reabsorption in kidneys, raising blood pressure.

• Atrial Natriuretic Factor (ANF): Peptide hormone produced by atria of heart, promoting sodium and water excretion to reduce blood volume and pressure.

• Aldosterone: Mineralocorticoid hormone from adrenal cortex that increases sodium reabsorption in kidneys, indirectly increasing blood pressure.

• Angiotensin-II: Potent vasoconstrictor hormone that increases blood pressure by narrowing blood vessels and stimulating aldosterone secretion.

• Blood Pressure: Force exerted by circulating blood on walls of blood vessels, regulated by neural and hormonal mechanisms.

• Kidney: Organ responsible for maintaining fluid and electrolyte balance, and controlling blood pressure through renin-angiotensin-aldosterone system.

• Vasodilation: Widening of blood vessels to reduce vascular resistance and lower blood pressure.

• Hormonal Regulation: Control of physiological processes by hormones secreted by endocrine glands.

Lead Question - 2022 (Abroad)
Which one of the following hormones reduces the blood pressure?
1. Antidiuretic hormone
2. Atrial Natriuretic factor
3. Aldosterone
4. Angiotensin-II
Explanation: The correct answer is Atrial Natriuretic factor. ANF is released from the atrial walls of the heart in response to high blood volume or pressure. It promotes natriuresis, the excretion of sodium and water by kidneys, leading to decreased blood volume and vasodilation, which together reduce blood pressure. Unlike ADH, aldosterone, and angiotensin-II, which increase blood pressure through water retention or vasoconstriction, ANF serves as a counter-regulatory hormone, maintaining cardiovascular homeostasis. It is essential in preventing hypertension and maintaining proper fluid and electrolyte balance, acting directly on renal tubules and blood vessels to lower vascular resistance and circulating volume.

1. Single Correct Answer Type:
Which hormone promotes water retention and increases blood pressure?
1. Atrial Natriuretic factor
2. Antidiuretic hormone
3. Prolactin
4. Cortisol
Explanation: The correct answer is Antidiuretic hormone. ADH is secreted by the posterior pituitary in response to dehydration or low blood volume. It increases water reabsorption in renal collecting ducts, reducing urine output, and raising blood pressure. ANF, in contrast, decreases blood pressure. ADH does not directly influence sodium excretion like aldosterone, and prolactin and cortisol have different physiological functions. By maintaining blood volume, ADH is crucial for cardiovascular homeostasis, especially during fluid deficit or hemorrhage.

2. Single Correct Answer Type:
Which hormone directly causes vasodilation to reduce blood pressure?
1. Angiotensin-II
2. Atrial Natriuretic factor
3. Aldosterone
4. ADH
Explanation: The correct answer is Atrial Natriuretic factor. ANF binds to receptors on vascular smooth muscles and kidney cells, inducing vasodilation and promoting excretion of sodium and water. This combination lowers vascular resistance and blood volume, thereby decreasing blood pressure. Angiotensin-II and aldosterone increase pressure, and ADH primarily increases water reabsorption. ANF plays a crucial counter-regulatory role against hypertensive stimuli, maintaining homeostasis in the cardiovascular system and protecting organs from damage due to elevated blood pressure.

3. Single Correct Answer Type:
Aldosterone reduces blood pressure by:
1. Increasing sodium excretion
2. Increasing sodium retention
3. Promoting vasodilation
4. Inhibiting renin
Explanation: The correct answer is Increasing sodium retention. Aldosterone is a mineralocorticoid secreted from the adrenal cortex. It promotes sodium reabsorption in renal distal tubules and collecting ducts, leading to water retention and increased blood volume, which raises blood pressure. It does not reduce pressure or promote vasodilation. ANF, not aldosterone, reduces blood pressure. Aldosterone’s action is part of the renin-angiotensin-aldosterone system that regulates fluid balance and blood pressure, crucial for maintaining homeostasis in response to hypotension or low blood volume.

4. Single Correct Answer Type:
Angiotensin-II increases blood pressure primarily by:
1. Stimulating vasodilation
2. Stimulating aldosterone secretion and vasoconstriction
3. Inhibiting ADH
4. Increasing sodium excretion
Explanation: The correct answer is Stimulating aldosterone secretion and vasoconstriction. Angiotensin-II is a potent vasoconstrictor that narrows arterioles, increasing vascular resistance. It also stimulates aldosterone release from adrenal cortex, promoting sodium and water retention, which raises blood volume and pressure. This mechanism contrasts with ANF, which lowers blood pressure. Angiotensin-II is central to the renin-angiotensin-aldosterone system, regulating blood pressure and fluid balance in response to hypotension or dehydration, ensuring adequate perfusion to vital organs.

5. Single Correct Answer Type:
Which hormone’s release is triggered by increased atrial stretch due to high blood volume?
1. ADH
2. ANF
3. Aldosterone
4. Angiotensin-II
Explanation: The correct answer is ANF. Atrial Natriuretic Factor is secreted by atrial myocytes when they detect increased blood volume and pressure, causing atrial stretch. ANF promotes sodium and water excretion and vasodilation, effectively reducing blood pressure. ADH, aldosterone, and angiotensin-II have opposite effects, conserving water and increasing pressure. ANF acts as a counter-regulatory hormone to prevent hypertension, maintain fluid balance, and protect cardiovascular tissues, ensuring homeostasis in response to volume overload conditions.

6. Single Correct Answer Type:
Which hormone counteracts the effects of aldosterone?
1. ADH
2. Angiotensin-II
3. Atrial Natriuretic factor
4. Cortisol
Explanation: The correct answer is Atrial Natriuretic factor. ANF opposes aldosterone by promoting sodium and water excretion and vasodilation, reducing blood pressure. Aldosterone promotes sodium and water retention to raise pressure, while ANF decreases blood volume and vascular resistance. ADH and angiotensin-II enhance water retention and increase blood pressure. ANF maintains cardiovascular homeostasis, preventing hypertension and regulating fluid balance, acting as a physiological antagonist to the renin-angiotensin-aldosterone system.

7. Assertion-Reason Type:
Assertion (A): ANF lowers blood pressure.
Reason (R): ANF promotes sodium and water excretion and vasodilation.
1. Both A and R are correct, and R is the correct explanation of A
2. Both A and R are correct, but R is not the correct explanation of A
3. A is correct, R is false
4. A is false, R is true
Explanation: Correct answer is Both A and R are correct, and R is the correct explanation of A. ANF reduces blood pressure by promoting natriuresis and diuresis, decreasing blood volume. Additionally, it induces vasodilation, lowering vascular resistance. Together, these mechanisms counteract the effects of hormones like aldosterone and angiotensin-II, maintaining cardiovascular homeostasis. This regulation is critical for preventing hypertension, ensuring proper perfusion of organs, and protecting cardiac tissues from volume overload.

8. Matching Type:
Match the hormone with its primary effect on blood pressure:
A. ADH → (i) Decreases BP
B. ANF → (ii) Increases BP
C. Aldosterone → (iii) Increases BP via sodium retention
D. Angiotensin-II → (iv) Increases BP via vasoc

Topic: Endocrine System
Subtopic: Parathyroid Hormone

• Parathyroid Hormone (PTH): Hormone secreted by parathyroid glands regulating calcium and phosphate levels in blood.

• Bone Resorption: Process of breaking down bone tissue to release calcium into blood.

• Calcium (Ca2+): Essential mineral for bones, muscle function, nerve conduction, and blood clotting.

• Blood Calcium Reabsorption: Uptake of calcium from kidneys into blood to maintain calcium homeostasis.

• Calcium Absorption: Uptake of calcium from digested food in the small intestine.

• Metabolism of Carbohydrates: Chemical processes converting carbohydrates into energy for cells.

• Endocrine System: Collection of glands that secrete hormones directly into the bloodstream.

• Homeostasis: Regulation of stable internal environment, including calcium levels.

• Phosphate: Mineral involved in bone formation and energy metabolism.

• Target Organs: Organs that respond to specific hormones, e.g., bones, kidneys, intestines for PTH.

• Hormonal Regulation: Control of physiological processes through hormone secretion and feedback mechanisms.

Lead Question - 2022:
Which of the following are not the effects of Parathyroid hormone?
(a) Stimulates the process of bone resorption
(b) Decreases Ca2+ level in bone
(c) Reabsorption of Ca2+ level in blood
(d) Decreases the absorption of Ca2+ from digested food
(e) Increases metabolism of carbohydrates
Choose the most appropriate answer from the options given below:
(1) (b), (d) and (e) only
(2) (a) and (e) only
(3) (b) and (c) only
(4) (a) and (c) only

Explanation: The correct answer is (1) (b), (d) and (e) only. Parathyroid hormone increases blood calcium by stimulating bone resorption and calcium reabsorption in kidneys. It does not decrease calcium in bone, nor reduce intestinal absorption, nor affect carbohydrate metabolism. Thus, statements (b), (d), and (e) are not effects of PTH.

1. Single Correct Answer MCQ:
Which organ is the primary target of parathyroid hormone for calcium reabsorption?
(a) Liver
(b) Kidney
(c) Heart
(d) Pancreas

Explanation: The correct answer is (b) Kidney. Parathyroid hormone increases calcium reabsorption in the kidneys, reducing urinary calcium loss. It also stimulates bone resorption and indirectly enhances intestinal calcium absorption by activating vitamin D. These actions maintain blood calcium homeostasis efficiently.

2. Single Correct Answer MCQ:
How does PTH affect bone tissue?
(a) Decreases bone resorption
(b) Stimulates bone resorption
(c) Inhibits osteoclast activity
(d) Promotes bone formation only

Explanation: The correct answer is (b) Stimulates bone resorption. Parathyroid hormone activates osteoclasts, breaking down bone tissue to release calcium and phosphate into the blood. This is a key mechanism by which PTH maintains adequate blood calcium levels for vital physiological functions.

3. Single Correct Answer MCQ:
Which vitamin’s activation is indirectly stimulated by PTH to enhance calcium absorption?
(a) Vitamin A
(b) Vitamin D
(c) Vitamin E
(d) Vitamin K

Explanation: The correct answer is (b) Vitamin D. Parathyroid hormone stimulates kidneys to convert inactive vitamin D to calcitriol, the active form. Active vitamin D increases intestinal calcium absorption, complementing bone resorption and renal reabsorption, thereby maintaining blood calcium homeostasis effectively.

4. Single Correct Answer MCQ:
Excess PTH secretion may lead to which condition?
(a) Hypocalcemia
(b) Hypercalcemia
(c) Hypoglycemia
(d) Hyponatremia

Explanation: The correct answer is (b) Hypercalcemia. Excess parathyroid hormone elevates blood calcium levels via bone resorption, renal reabsorption, and intestinal absorption. Persistent hypercalcemia can cause kidney stones, bone weakness, and cardiac abnormalities, highlighting the importance of tight regulation of PTH secretion.

5. Single Correct Answer MCQ:
Which cell type is primarily activated by PTH in bones?
(a) Osteoblasts
(b) Osteoclasts
(c) Chondrocytes
(d) Fibroblasts

Explanation: The correct answer is (b) Osteoclasts. PTH indirectly stimulates osteoclasts by binding to osteoblasts, which release factors that activate osteoclasts. Osteoclasts resorb bone, releasing calcium and phosphate into the blood, maintaining proper calcium levels for physiological functions.

6. Single Correct Answer MCQ:
PTH secretion is regulated primarily by:
(a) Blood calcium levels
(b) Blood glucose levels
(c) Blood sodium levels
(d) Blood potassium levels

Explanation: The correct answer is (a) Blood calcium levels. Parathyroid glands sense calcium concentration via calcium-sensing receptors. Low blood calcium triggers PTH secretion, while high calcium suppresses it. This feedback mechanism ensures stable calcium homeostasis critical for neuromuscular function, bone integrity, and enzymatic processes.

7. Assertion-Reason MCQ:
Assertion (A): PTH enhances calcium absorption from intestines indirectly.
Reason (R): PTH activates vitamin D to increase intestinal calcium uptake.
(a) A is true, R is true and R is correct explanation of A
(b) A is true, R is true but R is not correct explanation of A
(c) A is true, R is false
(d) A is false, R is true

Explanation: The correct answer is (a) A is true, R is true and R is correct explanation of A. PTH stimulates kidneys to convert vitamin D to calcitriol, which increases intestinal calcium absorption. Thus, the assertion and reason are both true, and the reason correctly explains the assertion.

8. Matching Type MCQ:
Match the effects of PTH with the organ:
Column I: 1. Bone 2. Kidney 3. Intestine
Column II: a. Calcium reabsorption b. Calcium release c. Vitamin D mediated absorption
(a) 1-b, 2-a, 3-c
(b) 1-a, 2-b, 3-c
(c) 1-c, 2-b, 3-a
(d) 1-b, 2-c, 3-a

Explanation: The correct answer is (a) 1-b, 2-a, 3-c. PTH stimulates bone to release calcium (1-b), increases kidney calcium reabsorption (2-a), and indirectly enhances intestinal calcium absorption through vitamin D activation (3-c). Together, these maintain blood calcium homeostasis.

9. Fill in the Blanks MCQ:
Parathyroid hormone indirectly increases _________ absorption from intestines.
(a) Sodium
(b) Calcium
(c) Potassium
(d) Phosphate

Explanation: The correct answer is (b) Calcium. PTH activates vitamin D in kidneys, which enhances intestinal calcium absorption. This action complements bone resorption and renal reabsorption, collectively maintaining blood calcium levels essential for neuromuscular function, enzymatic reactions, and overall homeostasis.

10. Choose the Correct Statements MCQ:
Which of the following statements about PTH is/are correct?
(a) Stimulates bone resorption
(b) Decreases renal calcium reabsorption
(c) Increases intestinal calcium absorption indirectly
(d) Regulates blood phosphate levels

Explanation: The correct answer is (a), (c), (d). PTH stimulates bone resorption (a), enhances intestinal calcium absorption indirectly via vitamin D (c), and regulates phosphate levels by increasing renal phosphate excretion (d). Statement (b) is incorrect because PTH increases renal calcium reabsorption to maintain blood calcium homeostasis.

Subtopic: Parturition

Keyword Definitions:

• Parturition: The process of giving birth to a baby.

• Prostaglandins: Hormone-like substances involved in initiating labor contractions.

• Oxytocin: Hormone that stimulates uterine contractions and milk ejection.

• Prolactin: Hormone responsible for milk production, not directly involved in labor initiation.

• Estrogen: Hormone increasing uterine sensitivity to oxytocin, facilitating labor.

• Progesterone: Hormone maintaining pregnancy; decreased ratio triggers labor.

Lead Question - 2021

Which of these is not an important component of initiation of parturition in humans?

(1) Synthesis of prostaglandins
(2) Release of Oxytocin
(3) Release of Prolactin
(4) Increase in estrogen and progesterone ratio

Explanation: Parturition initiation involves prostaglandins, oxytocin, and a rise in estrogen-to-progesterone ratio, which stimulate uterine contractions. Prolactin is primarily responsible for lactation and is not directly involved in labor onset. Therefore, the correct answer is option (3) Release of Prolactin.

1. Which hormone stimulates milk ejection during lactation?
(1) Prolactin
(2) Oxytocin
(3) Progesterone
(4) Estrogen
Explanation: Oxytocin is responsible for milk ejection by causing contraction of myoepithelial cells around alveoli. Prolactin stimulates milk production but not ejection. Thus, the correct answer is option (2) Oxytocin.

2. The ratio of estrogen to progesterone increases during labor to:
(1) Maintain pregnancy
(2) Stimulate uterine contractions
(3) Inhibit prostaglandin synthesis
(4) Prevent oxytocin release
Explanation: An increase in the estrogen-to-progesterone ratio enhances uterine contractility and oxytocin sensitivity, promoting labor. Progesterone decline removes relaxation effects on uterus. Thus, the correct answer is option (2) Stimulate uterine contractions.

3. Which prostaglandins are involved in initiating labor?
(1) PGF2α and PGE2
(2) PGI2 and TXA2
(3) PGE1 and PGD2
(4) PGF1α and PGI2
Explanation: PGF2α and PGE2 are critical for cervical ripening and uterine contraction. They are synthesized by decidua and fetal membranes to initiate labor. Other prostaglandins have minor roles. Correct answer is option (1) PGF2α and PGE2.

4. Which hormone’s sudden withdrawal triggers labor?
(1) Estrogen
(2) Progesterone
(3) Oxytocin
(4) Prolactin
Explanation: Withdrawal of progesterone at term reduces uterine relaxation, allowing contractions. Estrogen levels rise to increase oxytocin receptors. Progesterone maintains pregnancy, so its decrease is essential. Correct answer is option (2) Progesterone.

5. During parturition, oxytocin is released from:
(1) Anterior pituitary
(2) Posterior pituitary
(3) Placenta
(4) Adrenal cortex
Explanation: Oxytocin is synthesized in hypothalamus and released from posterior pituitary. It stimulates uterine smooth muscle contraction during labor. Anterior pituitary secretes prolactin instead. Correct answer is option (2) Posterior pituitary.

6. Which of the following initiates cervical ripening?
(1) Oxytocin
(2) Prostaglandins
(3) Estrogen
(4) Progesterone
Explanation: Prostaglandins, mainly PGE2, soften and dilate the cervix (cervical ripening), facilitating labor. Oxytocin stimulates contractions but does not directly ripen cervix. Correct answer is option (2) Prostaglandins.

7. Assertion-Reason Question:
Assertion (A): Oxytocin stimulates uterine contractions during labor.
Reason (R): It increases calcium ion influx into uterine smooth muscle cells.
(1) Both A and R are true, R is correct explanation of A
(2) Both A and R are true, R is not correct explanation of A
(3) A true, R false
(4) A false, R true
Explanation: Oxytocin binds receptors on uterine smooth muscle, activating calcium influx, which triggers contraction. Both statements are true, and the reason correctly explains the assertion. Correct answer is option (1).

8. Matching Type Question:
Match hormone with function:
A. Prostaglandins - 1. Milk production
B. Oxytocin - 2. Uterine contractions
C. Prolactin - 3. Cervical ripening
D. Progesterone - 4. Maintains pregnancy
(1) A-3, B-2, C-1, D-4
(2) A-2, B-3, C-4, D-1
(3) A-1, B-4, C-2, D-3
(4) A-4, B-1, C-3, D-2
Explanation: Prostaglandins ripen cervix (A-3), oxytocin stimulates uterine contractions (B-2), prolactin promotes milk production (C-1), and progesterone maintains pregnancy (D-4). Correct answer is option (1).

9. Fill in the Blanks:
_________ hormone is mainly responsible for maintaining uterine quiescence during pregnancy.
(1) Progesterone
(2) Estrogen
(3) Oxytocin
(4) Prostaglandin
Explanation: Progesterone maintains uterine relaxation and prevents contractions during pregnancy. Its withdrawal near term allows labor initiation. Correct answer is option (1) Progesterone.

10. Choose the correct statements:
(a) Prolactin initiates labor.
(b) Oxytocin stimulates uterine contractions.
(c) Prostaglandins facilitate cervical ripening.
(d) Estrogen increases oxytocin receptor expression.
(1) b, c, d
(2) a, b, d
(3) a, c, d
(4) a, b, c, d
Explanation: Oxytocin stimulates contractions, prostaglandins aid cervical ripening, and estrogen increases uterine oxytocin receptors. Prolactin is not involved in labor initiation. Correct answer is option (1) b, c, d.

Subtopic: Hormonal Regulation of Blood Cells

• Erythropoietin (EPO): Hormone that stimulates red blood cell production in the bone marrow.

• Juxtaglomerular Cells: Specialized kidney cells that detect blood oxygen levels and secrete erythropoietin.

• Rostral Adenohypophysis: Anterior pituitary lobe that secretes various hormones, not EPO.

• Alpha Cells: Pancreatic cells that secrete glucagon, not EPO.

• Bone Marrow: Site of hematopoiesis where erythrocytes are produced.

• RBC Formation: Production of red blood cells stimulated by erythropoietin.

• Hypoxia: Low oxygen levels in tissues triggering erythropoietin release.

• Endocrine Hormones: Chemical messengers secreted by glands into blood to regulate body functions.

• Feedback Regulation: Mechanism controlling hormone release based on physiological need.

• Hematopoietic Stem Cells: Precursor cells in bone marrow giving rise to blood cells.

• Kidney Function: Erythropoietin secretion is part of kidney response to hypoxia.

Lead Question - 2021

Erythropoietin hormone which stimulates R.B.C. formation is produced by :

Options:
1. The cells of rostral adenohypophysis
2. The cells of bone marrow
3. Juxtaglomerular cells of the kidney
4. Alpha cells of pancreas

Explanation: Erythropoietin is secreted by juxtaglomerular cells of the kidney in response to hypoxia. It stimulates the bone marrow to produce red blood cells, ensuring oxygen transport in the body. Pituitary and pancreatic cells do not secrete this hormone. Answer: Juxtaglomerular cells of the kidney.

1. Which condition triggers erythropoietin secretion?
Options:
A. High oxygen levels
B. Low oxygen levels (hypoxia)
C. High glucose
D. Low calcium

Explanation: Hypoxia or low oxygen concentration stimulates juxtaglomerular cells to secrete erythropoietin, enhancing RBC production to improve oxygen delivery. High oxygen or unrelated signals like glucose do not trigger EPO. Answer: Low oxygen levels (hypoxia).

2. What is the main site of RBC production stimulated by erythropoietin?
Options:
A. Kidney
B. Liver
C. Bone marrow
D. Spleen

Explanation: Bone marrow contains hematopoietic stem cells that differentiate into erythrocytes. Erythropoietin secreted by kidney cells acts on these stem cells to increase RBC production. The kidney produces the hormone, not the cells directly. Answer: Bone marrow.

3. Which organ does not produce erythropoietin?
Options:
A. Kidney
B. Liver (adult)
C. Rostral adenohypophysis
D. Juxtaglomerular cells

Explanation: In adults, the kidney juxtaglomerular cells secrete erythropoietin. The rostral adenohypophysis (anterior pituitary) does not produce EPO. The fetal liver can produce some EPO, but in adults, liver contribution is minimal. Answer: Rostral adenohypophysis.

4. Erythropoietin primarily acts on:
Options:
A. Alpha cells of pancreas
B. Hematopoietic stem cells in bone marrow
C. Kidney tubules
D. Liver hepatocytes

Explanation: Erythropoietin targets hematopoietic stem cells in the bone marrow to stimulate proliferation and differentiation into red blood cells, thereby increasing oxygen-carrying capacity. Other organs are not the primary targets. Answer: Hematopoietic stem cells in bone marrow.

5. Which pancreatic cells are unrelated to erythropoietin?
Options:
A. Beta cells
B. Alpha cells
C. Delta cells
D. All of the above

Explanation: Pancreatic cells, including alpha, beta, and delta cells, secrete hormones like glucagon, insulin, and somatostatin. They are unrelated to erythropoietin secretion. Kidney juxtaglomerular cells produce EPO, not pancreatic cells. Answer: All of the above.

6. Which of these hormones regulates RBC production?
Options:
A. Insulin
B. Erythropoietin
C. Cortisol
D. Thyroxine

Explanation: Erythropoietin specifically regulates red blood cell formation by acting on bone marrow hematopoietic stem cells. Other hormones regulate metabolism, stress, or growth. Answer: Erythropoietin.

7. Assertion-Reason:
Assertion (A): Kidney secretes erythropoietin in response to hypoxia.
Reason (R): Low oxygen stimulates juxtaglomerular cells to produce EPO.
Options:
A. Both A and R are true, R is correct explanation
B. Both A and R are true, R is not correct explanation
C. A is true, R is false
D. A is false, R is true

Explanation: The kidney detects hypoxia and juxtaglomerular cells respond by secreting erythropoietin to stimulate RBC formation in bone marrow. The reason accurately explains the assertion. Answer: Both A and R are true, R is correct explanation.

8. Match the following:
Column I: 1. Erythropoietin 2. Alpha cells 3. Beta cells 4. Delta cells
Column II: A. Secretes insulin B. Secretes glucagon C. Stimulates RBC production D. Secretes somatostatin
Options:
A. 1-C, 2-B, 3-A, 4-D
B. 1-B, 2-C, 3-D, 4-A
C. 1-A, 2-B, 3-C, 4-D
D. 1-D, 2-A, 3-B, 4-C

Explanation: Correct matching: Erythropoietin – RBC production (C), Alpha cells – Glucagon (B), Beta cells – Insulin (A), Delta cells – Somatostatin (D). Answer: 1-C, 2-B, 3-A, 4-D.

Topic: Endocrine Functions in Reproduction
Subtopic: Hormone Secretion and Source Organs

Keyword Definitions:

• Ovary: Female reproductive organ producing eggs and hormones like estrogen and progesterone.

• Placenta: Temporary organ connecting fetus to uterine wall, secretes hormones to maintain pregnancy.

• Corpus luteum: Temporary endocrine structure formed after ovulation, secretes progesterone and some estrogen.

• Leydig cells: Cells in testes producing androgens, primarily testosterone.

• Human chorionic gonadotropin (hCG): Hormone secreted by placenta, maintains corpus luteum in early pregnancy.

• Estrogen: Female sex hormone, promotes secondary sexual characteristics and endometrial growth.

• Progesterone: Hormone maintaining uterine lining for pregnancy.

• Androgens: Male sex hormones, mainly testosterone, supporting male reproductive functions.

Lead Question - 2020 (COVID Reexam)

Match the following columns and select the correct option:

Column - I    Column - II
(a) Ovary    (i) Human chorionic Gonadotropin
(b) Placenta    (ii) Estrogen & Progesterone
(c) Corpus luteum    (iii) Androgens
(d) Leydig cells    (iv) Progesterone only

1. (a)-(iv), (b)-(iii), (c)-(ii), (d)-(i)
2. (a)-(i), (b)-(ii), (c)-(iii), (d)-(iv)
3. (a)-(i), (b)-(iii), (c)-(ii), (d)-(iv)
4. (a)-(ii), (b)-(i), (c)-(iv), (d)-(iii)

Explanation: Ovary produces estrogen and progesterone, corpus luteum secretes progesterone mainly, placenta produces hCG in early pregnancy, and Leydig cells produce androgens like testosterone. Correct matching is (a)-(ii), (b)-(i), (c)-(iv), (d)-(iii). Answer: Option 4.

1. Single correct answer MCQ:

Which organ secretes androgens?
1. Ovary
2. Placenta
3. Leydig cells
4. Corpus luteum

Explanation: Leydig cells in the testes secrete androgens, primarily testosterone, which regulates male reproductive functions and secondary sexual characteristics. Ovary, placenta, and corpus luteum do not secrete androgens. Answer: Option 3.

2. Single correct answer MCQ:

Which hormone is secreted by corpus luteum?
1. Estrogen only
2. Progesterone only
3. hCG
4. Testosterone

Explanation: Corpus luteum secretes mainly progesterone to maintain the uterine lining for pregnancy. It also secretes some estrogen, but progesterone predominates. Answer: Option 2.

3. Single correct answer MCQ:

Which hormone is secreted by placenta in early pregnancy?
1. Estrogen
2. Progesterone
3. hCG
4. Testosterone

Explanation: Placenta secretes human chorionic gonadotropin (hCG) during early pregnancy to maintain corpus luteum, ensuring continuous progesterone production and supporting pregnancy. Answer: Option 3.

4. Single correct answer MCQ:

Ovary mainly secretes:
1. Testosterone
2. hCG
3. Estrogen and Progesterone
4. Prolactin

Explanation: Ovaries produce female sex hormones, estrogen and progesterone, which regulate menstrual cycles, secondary sexual characteristics, and prepare endometrium for pregnancy. Answer: Option 3.

5. Single correct answer MCQ:

Which structure maintains early pregnancy by progesterone secretion?
1. Placenta
2. Corpus luteum
3. Ovary
4. Leydig cells

Explanation: Corpus luteum secretes progesterone during early pregnancy to maintain the uterine lining. Placenta takes over hormone production later. Ovary and Leydig cells are not primarily responsible for early progesterone secretion. Answer: Option 2.

6. Single correct answer MCQ:

Which hormone is not secreted by ovary?
1. Estrogen
2. Progesterone
3. Androgens
4. All are secreted

Explanation: Ovary secretes estrogen and progesterone but produces minimal androgens. Leydig cells are the main source of androgens. Therefore, androgens are not secreted by the ovary. Answer: Option 3.

7. Assertion-Reason MCQ:

Assertion (A): Leydig cells produce testosterone.
Reason (R): Testosterone is an androgen secreted by Leydig cells in testes.
1. Both A and R true, R correct explanation
2. Both A and R true, R not correct explanation
3. A true, R false
4. A false, R true

Explanation: Leydig cells in testes produce testosterone, which is an androgen. Reason accurately explains the assertion. Answer: Option 1.

8. Matching Type MCQ:

Column I    Column II
(a) Ovary    (i) Estrogen & Progesterone
(b) Placenta    (ii) hCG
(c) Corpus luteum    (iii) Progesterone only
(d) Leydig cells    (iv) Androgens

1. (a)-(i), (b)-(ii), (c)-(iii), (d)-(iv)
2. (a)-(ii), (b)-(i), (c)-(iv), (d)-(iii)
3. (a)-(iii), (b)-(iv), (c)-(i), (d)-(ii)
4. (a)-(iv), (b)-(iii), (c)-(ii), (d)-(i)

Explanation: Ovary secretes estrogen and progesterone, placenta produces hCG, corpus luteum secretes progesterone, Leydig cells produce androgens. Correct matching is (a)-(i), (b)-(ii), (c)-(iii), (d)-(iv). Answer: Option 1.

9. Fill in the blanks:

The hormone that maintains corpus luteum during early pregnancy is ________.
1. Progesterone
2. Estrogen
3. hCG
4. Testosterone

Explanation: Human chorionic gonadotropin (hCG) secreted by placenta maintains the corpus luteum during early pregnancy, ensuring continued progesterone production to support uterine lining. Answer: Option 3.

10. Choose correct statements:

(a) Corpus luteum secretes progesterone
(b) Placenta secretes hCG
(c) Leydig cells produce estrogen
(d) Ovary produces estrogen and progesterone

1. a, b, d only
2. a and c only
3. b and c only
4. All statements correct

Explanation: Corpus luteum secretes progesterone, placenta secretes hCG, and ovary produces estrogen and progesterone. Leydig cells produce androgens, not estrogen. Therefore, correct statements are a, b, and d only. Answer: Option 1.

Topic: Pituitary Gland
Subtopic: Neurohypophysis Hormones

Keyword Definitions:

• Neurohypophysis: Also called posterior pituitary, it stores and releases hormones secreted by hypothalamus.

• Oxytocin: Hormone responsible for uterine contraction during childbirth and milk ejection during lactation.

• Vasopressin (ADH): Antidiuretic hormone that increases water reabsorption in kidneys, reducing urine output.

• TSH: Thyroid-stimulating hormone produced by anterior pituitary, not stored in neurohypophysis.

Lead Question - 2020 (COVID Reexam)

Hormones stored and released from neurohypophysis are:-

1. Thyroid-stimulating hormone and Oxytocin
2. Oxytocin and Vasopressin
3. Follicle-stimulating hormone and luteinizing hormone
4. Prolactin and Vasopressin

Explanation: The neurohypophysis or posterior pituitary stores and releases two hypothalamic hormones: oxytocin and vasopressin (ADH). Oxytocin aids childbirth and lactation, while vasopressin regulates water balance. TSH, FSH, LH, and prolactin are secreted by the anterior pituitary. Answer: Option 2.

1. Which lobe of pituitary stores oxytocin?

1. Anterior lobe
2. Intermediate lobe
3. Posterior lobe
4. Hypothalamus

Explanation: Oxytocin is synthesized by hypothalamic neurons and stored in the posterior lobe of pituitary (neurohypophysis). It is released during childbirth and lactation. The anterior lobe produces tropic hormones. Answer: Option 3.

2. Which hormone prevents excessive water loss through urine?

1. Aldosterone
2. Vasopressin
3. Cortisol
4. Prolactin

Explanation: Vasopressin (ADH) secreted by hypothalamus and released from posterior pituitary increases water reabsorption in kidneys, reducing urine output and maintaining osmotic balance. Aldosterone acts on sodium reabsorption, not direct water retention. Answer: Option 2.

3. Oxytocin plays an important role in:

1. Milk ejection
2. Blood pressure regulation
3. Sodium balance
4. Protein metabolism

Explanation: Oxytocin is essential for uterine contractions during parturition and milk ejection during lactation. It does not regulate sodium, pressure, or protein metabolism. Answer: Option 1.

4. Assertion (A): Neurohypophysis produces oxytocin.
Reason (R): Oxytocin is synthesized by hypothalamic neurons and stored in neurohypophysis.

1. Both A and R are true, R is correct explanation
2. Both A and R are true, R not correct explanation
3. A false, R true
4. A true, R false

Explanation: Oxytocin is not produced in neurohypophysis but in hypothalamus. It is only stored and released by neurohypophysis. So assertion is false, reason is true. Answer: Option 3.

5. Match the following:
Column-I     Column-II
(a) Vasopressin     (i) Uterine contraction
(b) Oxytocin     (ii) Water reabsorption
(c) TSH     (iii) Stimulates thyroid
(d) Prolactin     (iv) Milk production

1. (a)-(ii), (b)-(i), (c)-(iii), (d)-(iv)
2. (a)-(iii), (b)-(ii), (c)-(i), (d)-(iv)
3. (a)-(iv), (b)-(iii), (c)-(ii), (d)-(i)
4. (a)-(i), (b)-(iv), (c)-(iii), (d)-(ii)

Explanation: Vasopressin regulates water reabsorption, oxytocin causes uterine contractions, TSH stimulates thyroid, and prolactin induces milk production. Correct answer is (a)-(ii), (b)-(i), (c)-(iii), (d)-(iv). Answer: Option 1.

6. Fill in the blank:
Deficiency of vasopressin causes a disorder called ______.

1. Diabetes mellitus
2. Diabetes insipidus
3. Addison’s disease
4. Cushing’s syndrome

Explanation: Deficiency of vasopressin results in diabetes insipidus characterized by excessive thirst and dilute urine. Diabetes mellitus is due to insulin deficiency. Answer: Option 2.

7. Choose the correct statements:
(a) Oxytocin stimulates uterine contraction.
(b) Vasopressin promotes water reabsorption.
(c) Both are stored in posterior pituitary.
(d) Both are secreted by anterior pituitary.

1. a, b, c only
2. b and d only
3. a and d only
4. a, b, c and d

Explanation: Oxytocin and vasopressin are synthesized in hypothalamus and stored in posterior pituitary. They stimulate uterine contraction and water reabsorption respectively. They are not secreted by anterior pituitary. Correct statements are a, b, c. Answer: Option 1.

8. Which disorder is linked to oxytocin deficiency?

1. Delayed labor
2. Diabetes insipidus
3. Goitre
4. Acromegaly

Explanation: Oxytocin deficiency can lead to weak or delayed labor due to insufficient uterine contractions. Diabetes insipidus is due to vasopressin deficiency, goitre is thyroid related, and acromegaly is due to growth hormone excess. Answer: Option 1.

9. Which pituitary hormone promotes milk production?

1. Prolactin
2. Oxytocin
3. Vasopressin
4. TSH

Explanation: Prolactin secreted by anterior pituitary stimulates milk production in mammary glands after childbirth. Oxytocin only aids milk ejection, not production. Vasopressin regulates water, TSH stimulates thyroid. Answer: Option 1.

10. Which hypothalamic hormone controls vasopressin release?

1. CRH
2. ADH releasing hormone
3. Osmoreceptor signals
4. GHRH

Explanation: Vasopressin release is controlled by hypothalamic osmoreceptor signals that detect blood osmolarity changes. Increased osmolarity triggers release from posterior pituitary. CRH controls ACTH, GHRH controls growth hormone. Answer: Option 3.

Subtopic: Hormone Types and Functions

Keyword Definitions:

• Pituitary Hormone: Secreted by the pituitary gland, includes growth hormone, ACTH, TSH, which are mainly peptides and proteins.

• Epinephrine: A biogenic amine secreted by adrenal medulla, also called adrenaline, involved in fight-or-flight response.

• Endorphins: Neuropeptides functioning as natural painkillers and mood enhancers.

• Cortisol: A steroid hormone secreted by adrenal cortex, regulating metabolism and stress response.

Lead Question - 2020 (COVID Reexam)

Match the following columns and select the correct option:-

Column-I     Column-II
(a) Pituitary hormone     (i) Steroid
(b) Epinephrine     (ii) Neuropeptides
(c) Endorphins     (iii) Peptides, proteins
(d) Cortisol     (iv) Biogenic amines

1. (a)-(iv), (b)-(i), (c)-(ii), (d)-(iii)
2. (a)-(iii), (b)-(iv), (c)-(ii), (d)-(i)
3. (a)-(iv), (b)-(iii), (c)-(i), (d)-(ii)
4. (a)-(iii), (b)-(iv), (c)-(i), (d)-(ii)

Explanation: Pituitary hormones are proteins or peptides, epinephrine is a biogenic amine, endorphins are neuropeptides, and cortisol is a steroid hormone. Thus, the correct match is (a)-(iii), (b)-(iv), (c)-(ii), (d)-(i). Answer: Option 2.

1. Which of the following is a steroid hormone?

1. Insulin
2. Cortisol
3. Oxytocin
4. Glucagon

Explanation: Cortisol is a steroid hormone secreted by the adrenal cortex. It regulates metabolism, suppresses inflammation, and is essential in stress responses. Insulin, oxytocin, and glucagon are peptide or protein hormones. Answer: Option 2.

2. Which of the following is secreted by the adrenal medulla?

1. Cortisol
2. Aldosterone
3. Epinephrine
4. Insulin

Explanation: Adrenal medulla secretes epinephrine and norepinephrine, which are biogenic amines. They prepare the body for stress or emergency through fight-or-flight responses. Cortisol and aldosterone are secreted by adrenal cortex, insulin by pancreas. Answer: Option 3.

3. Endorphins act as:

1. Stress hormones
2. Pain suppressors
3. Digestive enzymes
4. Growth regulators

Explanation: Endorphins are neuropeptides produced in the brain and pituitary gland. They bind to opioid receptors, reducing pain perception and inducing a feeling of well-being and euphoria. Thus, they act as natural pain suppressors. Answer: Option 2.

4. Which pituitary hormone stimulates the thyroid gland?

1. ACTH
2. TSH
3. LH
4. FSH

Explanation: Thyroid-stimulating hormone (TSH) is secreted by the anterior pituitary. It stimulates the thyroid gland to release thyroxine, which regulates metabolism. ACTH stimulates adrenal cortex, LH and FSH act on gonads. Answer: Option 2.

5. Assertion (A): Epinephrine increases blood glucose levels.
Reason (R): Epinephrine stimulates glycogen breakdown in liver and muscle.

1. Both A and R are true, R is correct explanation
2. Both A and R are true, R not correct explanation
3. A true, R false
4. A false, R true

Explanation: Epinephrine, secreted by adrenal medulla, increases blood glucose by stimulating glycogenolysis in liver and muscles. Both assertion and reason are true, and reason correctly explains assertion. Answer: Option 1.

6. Match the following:
Column-I     Column-II
(a) Insulin     (i) Raises blood sugar
(b) Glucagon     (ii) Lowers blood sugar
(c) Thyroxine     (iii) Regulates metabolism
(d) Oxytocin     (iv) Uterine contraction

1. (a)-(i), (b)-(ii), (c)-(iv), (d)-(iii)
2. (a)-(ii), (b)-(i), (c)-(iii), (d)-(iv)
3. (a)-(iii), (b)-(ii), (c)-(i), (d)-(iv)
4. (a)-(ii), (b)-(iv), (c)-(i), (d)-(iii)

Explanation: Insulin lowers blood sugar, glucagon raises blood sugar, thyroxine regulates metabolism, and oxytocin stimulates uterine contractions during childbirth. Thus, correct answer is (a)-(ii), (b)-(i), (c)-(iii), (d)-(iv). Answer: Option 2.

7. Fill in the blank:
The hormone secreted by the pineal gland is ______.

1. Melatonin
2. Calcitonin
3. Vasopressin
4. Prolactin

Explanation: The pineal gland secretes melatonin, which regulates biological rhythms such as sleep-wake cycles. Calcitonin is secreted by thyroid, vasopressin by posterior pituitary, prolactin by anterior pituitary. Answer: Option 1.

8. Choose the correct statements regarding hormones:
(a) Cortisol is a steroid
(b) Epinephrine is a peptide
(c) Insulin is a protein
(d) Endorphins are neuropeptides

1. a, c and d only
2. b and c only
3. a and b only
4. a, b, c and d

Explanation: Cortisol is a steroid hormone, insulin is a protein hormone, and endorphins are neuropeptides. Epinephrine is not a peptide but a biogenic amine. Correct statements are a, c and d. Answer: Option 1.

9. Which hormone regulates water reabsorption in kidney tubules?

1. Oxytocin
2. Vasopressin
3. Aldosterone
4. Cortisol

Explanation: Vasopressin (antidiuretic hormone, ADH) secreted by posterior pituitary increases water reabsorption in kidney tubules, reducing urine output. It maintains body fluid balance. Aldosterone regulates sodium reabsorption, cortisol regulates metabolism, oxytocin controls uterine contraction. Answer: Option 2.

10. Which endocrine gland is called the “master gland”?

1. Adrenal gland
2. Pituitary gland
3. Thyroid gland
4. Pancreas

Explanation: Pituitary gland is called the master gland because it secretes multiple hormones regulating other endocrine glands, such as thyroid, adrenal, and gonads. It controls growth, metabolism, reproduction, and stress responses. Answer: Option 2.

Subtopic: Glandular Functions and Related Diseases

Keyword Definitions:

• Pituitary gland – Master endocrine gland located at the base of the brain; regulates other endocrine glands via hormone secretion.

• Thyroid gland – Endocrine gland in the neck producing thyroxine and triiodothyronine; regulates metabolism and growth.

• Adrenal gland – Paired glands above kidneys producing cortisol, aldosterone, and adrenaline; involved in stress response and metabolism.

• Pancreas – Endocrine and exocrine gland producing insulin and glucagon; regulates blood glucose levels.

• Grave's disease – Autoimmune disorder causing hyperthyroidism, characterized by overproduction of thyroid hormones.

• Diabetes mellitus – Metabolic disorder caused by insulin deficiency or resistance, leading to hyperglycemia.

• Diabetes insipidus – Condition caused by deficiency of antidiuretic hormone (ADH), leading to excessive urination and thirst.

• Addison's disease – Chronic adrenal insufficiency resulting in low cortisol and aldosterone levels, causing fatigue, hypotension, and electrolyte imbalance.

• Hormones – Chemical messengers secreted by glands that regulate physiological activities.

• Endocrine system – Collection of glands that secrete hormones directly into the bloodstream to control body functions.

• Metabolic disorder – Condition that disrupts normal chemical processes in the body, often hormone-related.

Lead Question - 2020

Match the following columns and select the correct option.
Column - I   Column - II
(a) Pituitary gland  (i) Grave's disease
(b) Thyroid gland  (ii) Diabetes mellitus
(c) Adrenal gland  (iii) Diabetes insipidus
(d) Pancreas  (iv) Addison's disease

Options:
(1) a-iii, b-i, c-iv, d-ii
(2) a-ii, b-i, c-iv, d-iii
(3) a-iv, b-iii, c-i, d-ii
(4) a-iii, b-ii, c-i, d-iv

Explanation: Pituitary gland deficiency or excess causes diabetes insipidus (a-iii). Thyroid gland disorders include Grave’s disease (b-i). Adrenal insufficiency results in Addison's disease (c-iv). Pancreas dysfunction causes diabetes mellitus (d-ii). Correct matching corresponds to option (1).

1. Single Correct Answer: Which gland secretes insulin?
(1) Pituitary
(2) Thyroid
(3) Pancreas
(4) Adrenal

Explanation: The pancreas secretes insulin from beta cells in the islets of Langerhans, regulating blood glucose levels. Correct answer is (3) Pancreas.

2. Single Correct Answer: Which disease is caused by excess thyroid hormone?
(1) Addison's disease
(2) Diabetes insipidus
(3) Grave's disease
(4) Diabetes mellitus

Explanation: Grave’s disease is an autoimmune disorder causing hyperthyroidism, characterized by excessive thyroid hormone production, weight loss, and heat intolerance. Correct answer is (3) Grave's disease.

3. Single Correct Answer: Addison's disease primarily affects which gland?
(1) Thyroid
(2) Adrenal
(3) Pancreas
(4) Pituitary

Explanation: Addison’s disease is caused by chronic adrenal insufficiency, leading to low cortisol and aldosterone levels, causing fatigue, hypotension, and electrolyte imbalance. Correct answer is (2) Adrenal.

4. Assertion-Reason:
Assertion (A): Pituitary gland regulates water balance.
Reason (R): It secretes antidiuretic hormone controlling renal water reabsorption.
(1) Both A and R true, R explains A
(2) Both A and R true, R does not explain A
(3) A true, R false
(4) A false, R true

Explanation: The posterior pituitary secretes antidiuretic hormone (ADH) which regulates water reabsorption in kidneys. This directly controls water balance. Both assertion and reason are true, and R explains A. Correct answer is (1).

5. Single Correct Answer: Diabetes insipidus results from deficiency of:
(1) Insulin
(2) Thyroxine
(3) Antidiuretic hormone
(4) Cortisol

Explanation: Diabetes insipidus occurs due to deficiency of ADH secreted by the posterior pituitary, leading to polyuria and polydipsia. Correct answer is (3) Antidiuretic hormone.

6. Single Correct Answer: Which gland is called the master gland?
(1) Thyroid
(2) Pituitary
(3) Adrenal
(4) Pancreas

Explanation: Pituitary gland is called the master gland because it secretes hormones regulating other endocrine glands’ activity. Correct answer is (2) Pituitary.

7. Matching Type: Match the hormone with gland:
a. Cortisol – i. Pituitary
b. Thyroxine – ii. Thyroid
c. Insulin – iii. Pancreas
d. ADH – iv. Adrenal
Options:
(1) a-iv, b-ii, c-iii, d-i
(2) a-ii, b-iv, c-i, d-iii
(3) a-i, b-iii, c-ii, d-iv
(4) a-iii, b-i, c-iv, d-ii

Explanation: Cortisol is secreted by adrenal glands (a-iv), thyroxine by thyroid (b-ii), insulin by pancreas (c-iii), and ADH by pituitary (d-i). Correct answer is (1).

8. Fill in the blank: Excess of thyroid hormone leads to ______.
(1) Hypothyroidism
(2) Grave's disease
(3) Addison's disease
(4) Diabetes mellitus

Explanation: Excess thyroid hormone causes hyperthyroidism, commonly known as Grave’s disease. Correct answer is (2) Grave's disease.

9. Single Correct Answer: Which endocrine disorder results in low blood glucose control?
(1) Addison's disease
(2) Diabetes insipidus
(3) Diabetes mellitus
(4) Grave's disease

Explanation: Diabetes mellitus results from insulin deficiency or resistance, leading to high blood glucose and impaired glucose metabolism. Correct answer is (3) Diabetes mellitus.

10. Choose the correct statements:
(a) Pituitary secretes ADH
(b) Thyroid regulates metabolism
(c) Adrenal produces insulin

Subtopic: Hormones and Structures

Keyword Definitions:

• Placenta: Temporary organ that connects the fetus to the mother, secreting hormones like hCG.

• Zona pellucida: Glycoprotein-rich layer surrounding the ovum, important for fertilization.

• Bulbo-urethral glands: Glands producing mucus for lubrication of the penis.

• Leydig cells: Testicular cells that produce androgens such as testosterone.

• hCG: Human Chorionic Gonadotropin, hormone produced by placenta to maintain pregnancy.

• Androgens: Male sex hormones, mainly testosterone, secreted by Leydig cells.

• Fertilization: Fusion of male and female gametes, usually in the fallopian tube.

Lead Question - 2020

Match the following columns and select the correct option.

Column-I Column-II
(a) Placenta (i) Androgens
(b) Zona pellucida (ii) Human Chorionic Gonadotropin (hCG)
(c) Bulbo-urethral glands (iii) Layer of the ovum
(d) Leydig cells (iv) Lubrication of the Penis

(1) a-(iii), b-(ii), c-(iv), d-(i)
(2) a-(ii), b-(iii), c-(iv), d-(i)
(3) a-(iv), b-(iii), c-(i), d-(ii)
(4) a-(i), b-(iv), c-(ii), d-(iii)

Explanation: The correct answer is (2). Placenta secretes hCG to maintain pregnancy, Zona pellucida surrounds the ovum, Bulbo-urethral glands lubricate the penis, and Leydig cells produce androgens. This matching highlights structural and hormonal roles in reproduction, essential for fertilization, implantation, lubrication, and male sexual function, ensuring successful reproduction in humans.

1. Which hormone is essential to maintain pregnancy?
(1) Progesterone
(2) Oxytocin
(3) Testosterone
(4) Prolactin
Explanation: The correct answer is (1) Progesterone. It maintains the endometrial lining and prevents uterine contractions during pregnancy. It is secreted by the corpus luteum initially and later by the placenta. Without sufficient progesterone, implantation and continuation of pregnancy are not possible, making it critical for fetal development and maternal support.

2. The role of acrosome during fertilization is:
(1) To form the zona pellucida
(2) To dissolve the zona pellucida
(3) To secrete testosterone
(4) To secrete hCG
Explanation: The correct answer is (2) To dissolve the zona pellucida. Acrosome is a cap-like structure on the sperm head containing hydrolytic enzymes. These enzymes break down the zona pellucida of the ovum, allowing the sperm nucleus to fuse with the egg nucleus, completing fertilization and initiating zygote formation.

3. Which cells secrete testosterone in males?
(1) Sertoli cells
(2) Leydig cells
(3) Granulosa cells
(4) Acrosome cells
Explanation: The correct answer is (2) Leydig cells. Located in the interstitial spaces of testes, Leydig cells secrete androgens, mainly testosterone, under the influence of LH. Testosterone regulates spermatogenesis, development of male reproductive structures, and secondary sexual characters, making these cells vital for male reproductive physiology.

4. Which structure prevents polyspermy in fertilization?
(1) Placenta
(2) Zona pellucida
(3) Acrosome
(4) Seminal vesicles
Explanation: The correct answer is (2) Zona pellucida. After the entry of one sperm, zona pellucida undergoes a biochemical modification known as the cortical reaction, which blocks additional sperm entry. This ensures only one sperm fertilizes the egg, preventing polyspermy, which would otherwise lead to abnormal development of the zygote.

5. Which hormone is detected in pregnancy tests?
(1) Progesterone
(2) hCG
(3) LH
(4) Estrogen
Explanation: The correct answer is (2) hCG. Human Chorionic Gonadotropin, secreted by placenta after implantation, is detected in urine or blood during pregnancy tests. Its presence confirms conception. hCG supports the corpus luteum to continue progesterone secretion, which is necessary for maintaining the uterine lining and successful development of the embryo.

6. Which gland secretes fructose-rich fluid in semen?
(1) Prostate gland
(2) Seminal vesicles
(3) Bulbo-urethral glands
(4) Testes
Explanation: The correct answer is (2) Seminal vesicles. These glands secrete seminal fluid rich in fructose, which provides energy to spermatozoa. Seminal vesicle secretion forms a major part of semen volume, along with prostaglandins and other nutrients that support sperm motility and fertilization potential within the female reproductive tract.

7. Assertion-Reason: Assertion: Placenta secretes hCG. Reason: hCG prevents degeneration of corpus luteum.
(1) Both A and R true, R correct explanation
(2) Both A and R true, R not correct explanation
(3) A true, R false
(4) A false, R true
Explanation: The correct answer is (1). Placenta secretes hCG after implantation. hCG ensures the survival of the corpus luteum during early pregnancy, which continues secreting progesterone to maintain the uterine lining. This prevents menstruation and allows the embryo to implant and develop, making the reason a correct explanation of the assertion.

8. Match the following hormones with their sources:
(a) Oxytocin (i) Posterior pituitary
(b) Progesterone (ii) Corpus luteum
(c) Testosterone (iii) Leydig cells
(d) hCG (iv) Placenta
(1) a-i, b-ii, c-iii, d-iv
(2) a-iv, b-iii, c-ii, d-i
(3) a-iii, b-i, c-iv, d-ii
(4) a-ii, b-iv, c-i, d-iii
Explanation: The correct answer is (1). Oxytocin is secreted by posterior pituitary, Progesterone by corpus luteum, Testosterone by Leydig cells, and hCG by placenta. These hormones collectively regulate reproduction, pregnancy, childbirth, and male sexual function, ensuring coordinated physiological processes for survival and propagation of the species.

9. Fill in the blank: ______ prevents premature expulsion of the embryo.
(1) Oxytocin
(2) Progesterone
(3) Testosterone
(4) Relaxin
Explanation: The correct answer is (2) Progesterone. This hormone inhibits uterine contractions and maintains the endometrium during pregnancy. It is secreted by the corpus luteum and later by the placenta. By preventing premature uterine activity, progesterone ensures the embryo remains implanted and continues normal development throughout gestation.

10. Choose the correct statements:
(a) Leydig cells produce androgens.
(b) Placenta secretes hCG.
(c) Bulbo-urethral glands provide energy to sperm.
(d) Zona pellucida surrounds the ovum.
(1) a, b, c
(2) a, b, d
(3) b, c, d
(4) a, c, d
Explanation: The correct answer is (2). Leydig cells produce testosterone, Placenta secretes hCG, and Zona pellucida surrounds the ovum. Bulbo-urethral glands do not provide energy to sperm; they secrete mucus for lubrication. Energy to sperm is provided mainly by fructose-rich fluid from seminal vesicles.

Subtopic: Endocrine Disorders

Keyword Definitions:

• Diabetes Mellitus: A metabolic disorder marked by high blood sugar due to insulin deficiency or resistance.

• Ketonuria: Presence of ketone bodies in urine due to fat breakdown.

• Glycosuria: Excretion of glucose in urine, seen when blood sugar levels exceed renal threshold.

• Uremia: Accumulation of urea in blood due to kidney malfunction.

• Renal Calculi: Hard deposits of salts and minerals in kidneys, commonly known as kidney stones.

• Hyperglycemia: A condition characterized by abnormally high blood glucose levels.

Lead Question - 2020

Presence of which of the following conditions in urine are indicative of Diabetes Mellitus ?

(1) Ketonuria and Glycosuria
(2) Renal calculi and Hyperglycemia
(3) Uremia and Ketonuria
(4) Uremia and Renal Calculi

Explanation: The correct answer is (1) Ketonuria and Glycosuria. Diabetes Mellitus leads to poor glucose utilization and fat breakdown, causing glucose and ketones to appear in urine. These are characteristic diagnostic features of the condition. Uremia and renal calculi are not diagnostic markers for this disorder. Hyperglycemia refers to blood, not urine findings.

1. A patient shows elevated blood sugar after fasting. Which test confirms Diabetes Mellitus?
(1) Serum creatinine
(2) Oral glucose tolerance test
(3) Uric acid test
(4) ECG
Explanation: The correct answer is (2) Oral glucose tolerance test. It measures the body’s ability to metabolize glucose and diagnose Diabetes Mellitus. High fasting blood sugar and poor response to glucose load indicate disease. Other tests like creatinine or uric acid evaluate kidney and metabolism, not blood glucose handling.

2. Which hormone deficiency directly causes Diabetes Mellitus?
(1) Insulin
(2) Glucagon
(3) Thyroxine
(4) Cortisol
Explanation: The correct answer is (1) Insulin. Insulin deficiency or resistance prevents glucose uptake by cells, leading to hyperglycemia. Glucagon, thyroxine, and cortisol influence metabolism but do not directly cause diabetes. Insulin plays a central role in regulating blood glucose and energy balance, making its lack the defining cause of this disorder.

3. Prolonged uncontrolled Diabetes Mellitus may cause?
(1) Hypertension
(2) Diabetic nephropathy
(3) Osteoporosis
(4) Gout
Explanation: The correct answer is (2) Diabetic nephropathy. Chronic high glucose damages glomeruli, leading to proteinuria and kidney failure. Hypertension may coexist but is not a direct consequence. Osteoporosis and gout are unrelated. Nephropathy is a major complication of poorly controlled diabetes, causing progressive renal damage over time if untreated.

4. Which of the following is not a symptom of Diabetes Mellitus?
(1) Polyuria
(2) Polydipsia
(3) Polyphagia
(4) Jaundice
Explanation: The correct answer is (4) Jaundice. Diabetes Mellitus is typically characterized by polyuria, polydipsia, and polyphagia due to high blood glucose and osmotic effects. Jaundice, a yellowing of the skin due to bilirubin accumulation, is a liver-related symptom and is not directly linked to diabetes pathology or common presentation.

5. The immediate cause of Ketone body formation in diabetes is:
(1) Excess glucose
(2) Fatty acid breakdown
(3) Protein synthesis
(4) Glycogen storage
Explanation: The correct answer is (2) Fatty acid breakdown. In absence of insulin action, cells cannot utilize glucose properly, leading to lipolysis. Fatty acids undergo beta-oxidation, producing ketone bodies. This results in ketonuria and ketoacidosis. Excess glucose remains unused, glycogen storage is impaired, and protein synthesis is not the cause.

6. Which organ is primarily damaged by diabetic nephropathy?
(1) Liver
(2) Kidney
(3) Pancreas
(4) Heart
Explanation: The correct answer is (2) Kidney. Diabetic nephropathy results from long-term damage to kidney glomeruli due to high glucose levels. This leads to albuminuria and eventual renal failure. Liver, pancreas, and heart may also be affected in diabetes complications, but nephropathy specifically involves kidneys as the target organ.

7. Assertion-Reason: Diabetes Mellitus leads to excessive urination. Reason: High blood glucose increases osmotic pressure of urine.
(1) Both A and R true, R is correct explanation
(2) Both A and R true, R not correct explanation
(3) A true, R false
(4) A false, R true
Explanation: The correct answer is (1). Osmotic diuresis occurs when excess glucose in renal filtrate draws water into urine, causing polyuria. Thus, both assertion and reason are true, and the reason correctly explains the assertion.

8. Match the following complications with diabetes:
(a) Retinopathy (i) Eye damage
(b) Neuropathy (ii) Nerve damage
(c) Nephropathy (iii) Kidney damage
(d) Atherosclerosis (iv) Arterial damage
(1) a-ii, b-i, c-iii, d-iv
(2) a-i, b-ii, c-iii, d-iv
(3) a-iii, b-ii, c-i, d-iv
(4) a-iv, b-iii, c-ii, d-i
Explanation: The correct answer is (2). Retinopathy affects eyes, neuropathy damages nerves, nephropathy injures kidneys, and atherosclerosis affects arteries. These are common long-term complications of diabetes caused by chronic hyperglycemia and vascular damage. Proper glucose control helps in preventing or delaying these serious complications.

9. Fill in the blank: The autoimmune destruction of β-cells in pancreas leads to __________.
(1) Type 2 Diabetes
(2) Type 1 Diabetes
(3) Gestational Diabetes
(4) Secondary Diabetes
Explanation: The correct answer is (2) Type 1 Diabetes. Autoimmune reactions destroy insulin-producing β-cells of pancreas, leading to absolute insulin deficiency. This is distinct from type 2 diabetes, which involves insulin resistance. Gestational diabetes occurs in pregnancy, while secondary diabetes arises from other endocrine or systemic disorders.

10. Choose the correct statements:
(a) Glycosuria is due to high renal threshold.
(b) Insulin facilitates cellular glucose uptake.
(c) Diabetes Mellitus is associated with polyuria.
(d) Glucagon reduces blood glucose.
(1) a and b
(2) b and c
(3) c and d
(4) a and d
Explanation: The correct answer is (2). Insulin helps glucose entry into cells, and polyuria is a major feature of diabetes. Glycosuria occurs due to low renal threshold being exceeded, not high. Glucagon increases, not decreases, blood glucose. Thus only statements b and c are correct in this context.

Subtopic: Hormonal Regulation of Blood Glucose

• Insulin: Hormone produced by beta cells of pancreas; lowers blood glucose by facilitating cellular uptake and storage.

• Glucagon: Hormone secreted by alpha cells of pancreas; increases blood glucose by stimulating glycogenolysis and gluconeogenesis.

• Pancreatic cells: Cells in pancreas including alpha and beta cells responsible for hormone secretion.

• Adipocytes: Fat-storing cells influenced by insulin for glucose uptake and fat synthesis.

• Hyperglycemia: Condition of elevated blood glucose levels.

• Hypoglycemia: Condition of abnormally low blood glucose levels.

• Glucocorticoids: Steroid hormones from adrenal cortex; stimulate gluconeogenesis and influence metabolism.

• Gluconeogenesis: Formation of glucose from non-carbohydrate precursors such as amino acids.

• Glycogenolysis: Breakdown of glycogen into glucose in liver or muscle.

• Endocrine system: Hormonal system controlling metabolism, growth, and homeostasis.

• Blood glucose regulation: Homeostatic control of glucose levels by insulin, glucagon, and other hormones.

Lead Question (2020): Select the correct statement :

1. Insulin acts on pancreatic cells and adipocytes

2. Insulin is associated with hyperglycemia

3. Glucocorticoids stimulate gluconeogenesis

4. Glucagon is associated with hypoglycemia

Explanation: The correct answer is 3. Glucocorticoids, secreted from adrenal cortex, stimulate gluconeogenesis, raising blood glucose. Insulin lowers blood glucose and acts on adipocytes, not on pancreatic hormone secretion. Glucagon raises blood glucose, causing hyperglycemia, not hypoglycemia. Hence, statement 3 is correct in glucose metabolism regulation.

Guessed MCQs:

1. Question 1: Insulin primarily acts on:
   A. Liver cells
   B. Adipocytes
   C. Muscle cells
   D. All of the above
   Explanation: The correct answer is D. Insulin facilitates glucose uptake in muscle and fat cells, and inhibits hepatic glucose production, regulating blood glucose homeostasis effectively across multiple tissues.

2. Question 2: Glucagon increases blood glucose by:
   A. Glycogen synthesis
   B. Glycogenolysis and gluconeogenesis
   C. Fat storage
   D. Insulin secretion
   Explanation: The correct answer is B. Glucagon stimulates liver glycogen breakdown (glycogenolysis) and synthesis of new glucose (gluconeogenesis), thereby increasing blood glucose levels.

3. Question 3: Hypoglycemia results from:
   A. Excess glucagon
   B. Insulin overdose
   C. High glucocorticoids
   D. Fasting
   Explanation: The correct answer is B. Excess insulin leads to abnormally low blood glucose (hypoglycemia) as it promotes cellular uptake of glucose, reducing circulating levels.

4. Question 4: Hyperglycemia is associated with:
   A. Glucagon
   B. Insulin deficiency
   C. Glucocorticoid excess
   D. All of the above
   Explanation: The correct answer is D. Hyperglycemia occurs due to insufficient insulin, excessive glucagon, or glucocorticoid excess, all of which raise blood glucose levels through metabolic pathways.

5. Question 5: Glucocorticoids stimulate glucose production via:
   A. Glycolysis
   B. Gluconeogenesis
   C. Lipogenesis
   D. Glycogen storage
   Explanation: The correct answer is B. Glucocorticoids from adrenal cortex enhance gluconeogenesis, generating glucose from non-carbohydrate sources to maintain blood glucose during stress.

6. Question 6: Insulin lowers blood glucose by:
   A. Promoting glycogen breakdown
   B. Facilitating cellular glucose uptake
   C. Stimulating gluconeogenesis
   D. Reducing glucose utilization
   Explanation: The correct answer is B. Insulin stimulates uptake of glucose by adipocytes and muscle cells, promotes glycogen formation, and reduces blood glucose to maintain homeostasis.

7. Question 7: Assertion-Reason:
   Assertion (A): Glucocorticoids raise blood glucose.
   Reason (R): They stimulate gluconeogenesis in the liver.
   A. Both A and R are true, R is correct explanation
   B. Both A and R are true, R is not correct explanation
   C. A true, R false
   D. A false, R true
   Explanation: The correct answer is A. Glucocorticoids increase blood glucose by stimulating gluconeogenesis in the liver, providing energy during stress and fasting. This mechanism directly explains the assertion.

8. Question 8: Matching Type: Match hormone with effect:
   i. Insulin - A. Lowers blood glucose
   ii. Glucagon - B. Raises blood glucose
   iii. Glucocorticoids - C. Stimulates gluconeogenesis
   iv. Epinephrine - D. Mobilizes glucose rapidly
   Choices:
   A. i-A, ii-B, iii-C, iv-D
   B. i-B, ii-A, iii-D, iv-C
   C. i-C, ii-D, iii-A, iv-B
   D. i-D, ii-C, iii-B, iv-A
   Explanation: The correct answer is A. Insulin lowers glucose (i-A), glucagon raises glucose (ii-B), glucocorticoids stimulate gluconeogenesis (iii-C), and epinephrine mobilizes glucose rapidly during stress (iv-D).

9. Question 9: Fill in the Blanks: ________ is secreted by beta cells of pancreas and lowers blood glucose.
   A. Glucagon
   B. Insulin
   C. Cortisol
   D. Adrenaline
   Explanation: The correct answer is B. Insulin, secreted by beta cells, reduces blood glucose by promoting uptake into cells, glycogen formation, and inhibiting glucose production in the liver.

10. Question 10: Choose the correct statements:
    i. Insulin lowers blood glucose
    ii. Glucagon raises blood glucose
    iii. Glucocorticoids stimulate gluconeogenesis
    iv. Excess insulin causes hyperglycemia
    A. i, ii, iii
    B. i, ii, iv
    C. ii, iii, iv
    D. i, iii, iv
    Explanation: The correct answer is A. Insulin lowers blood glucose (i), glucagon raises it (ii), glucocorticoids stimulate gluconeogenesis (iii). Excess insulin causes hypoglycemia, not hyperglycemia, so iv is incorrect.

Subtopic: Ovulation and Hormonal Control

• Ovulation: Release of a mature ovum from the Graafian follicle into the fallopian tube.

• Graafian Follicle: Mature ovarian follicle that contains the ovum ready for release during ovulation.

• Luteinizing Hormone (LH): Pituitary hormone that triggers ovulation and formation of corpus luteum.

• Follicle Stimulating Hormone (FSH): Pituitary hormone that stimulates follicular growth and maturation of the ovum.

• Estrogen: Ovarian hormone that regulates menstrual cycle and triggers LH surge at ovulation.

• Progesterone: Hormone secreted by corpus luteum post-ovulation that prepares endometrium for implantation.

• Hormonal Surge: Rapid increase in hormone concentration that triggers physiological events.

• Menstrual Cycle: Monthly cyclic changes in the ovary and uterus controlled by hormones.

• Corpus Luteum: Structure formed from the ruptured follicle after ovulation, secreting progesterone.

• Endometrium: Lining of the uterus that thickens under estrogen and progesterone for potential implantation.

• Feedback Mechanism: Regulation of hormone secretion by positive or negative feedback on the hypothalamus and pituitary.

Lead Question (2020): Which of the following hormone levels will cause release of ovum (ovulation) from the Graafian follicle?
Options:
1. Low concentration of LH
2. Low concentration of FSH
3. High concentration of Estrogen
4. High concentration of Progesterone

Explanation: Correct answer is 3. High concentration of estrogen from the mature follicle induces a positive feedback on the anterior pituitary, causing a surge in LH and FSH, which triggers ovulation. Low LH or FSH cannot initiate ovulation, and high progesterone occurs after ovulation, not before.

1. Single Correct Answer MCQ:
Which hormone surge directly triggers ovulation?
Options:
a. LH
b. FSH
c. Estrogen
d. Progesterone

Explanation: Correct answer is a. Luteinizing hormone surge from the anterior pituitary triggers the rupture of the Graafian follicle and release of the ovum, marking ovulation.

2. Single Correct Answer MCQ:
Which hormone is primarily responsible for follicular growth?
Options:
a. LH
b. FSH
c. Estrogen
d. Progesterone

Explanation: Correct answer is b. FSH stimulates the growth and maturation of ovarian follicles during the follicular phase of the menstrual cycle, preparing the ovum for ovulation.

3. Single Correct Answer MCQ:
Which hormone maintains endometrium after ovulation?
Options:
a. LH
b. FSH
c. Progesterone
d. Estrogen

Explanation: Correct answer is c. Progesterone secreted by the corpus luteum after ovulation stabilizes and thickens the endometrial lining to support potential implantation.

4. Single Correct Answer MCQ:
Estrogen triggers ovulation by:
Options:
a. Positive feedback on pituitary to release LH
b. Negative feedback on FSH
c. Directly rupturing the follicle
d. Increasing progesterone

Explanation: Correct answer is a. High estrogen levels from the mature follicle act on the anterior pituitary to cause a surge in LH and FSH, which then induces ovulation.

5. Single Correct Answer MCQ:
Low levels of which hormone cannot induce ovulation?
Options:
a. LH
b. Estrogen
c. Progesterone
d. FSH

Explanation: Correct answer is a. Low LH cannot trigger follicle rupture. LH surge is essential for ovulation, while low FSH can support follicular growth if combined with other hormones.

6. Single Correct Answer MCQ:
During which phase of the menstrual cycle is estrogen highest?
Options:
a. Menstrual phase
b. Follicular phase
c. Luteal phase
d. Ovulatory phase

Explanation: Correct answer is d. Estrogen peaks just before ovulation during the ovulatory phase, causing positive feedback on the pituitary and inducing LH surge for ovum release.

7. Assertion-Reason MCQ:
Assertion (A): High estrogen levels cause ovulation.
Reason (R): Estrogen induces a positive feedback on anterior pituitary leading to LH surge.
Options:
a. Both A and R are true, R explains A
b. Both A and R are true, R does not explain A
c. A is true, R is false
d. A is false, R is true

Explanation: Correct answer is a. High estrogen levels stimulate the anterior pituitary via positive feedback, causing a surge in LH, which directly triggers ovulation, making both assertion and reason true with the reason explanatory.

8. Matching Type MCQ:
Match the hormone with function:
(a) LH - (i) Follicle growth
(b) FSH - (ii) Ovulation
(c) Progesterone - (iii) Endometrium maintenance
(d) Estrogen - (iv) LH surge
Options:
1. a-ii, b-i, c-iii, d-iv
2. a-i, b-ii, c-iv, d-iii
3. a-iv, b-ii, c-i, d-iii
4. a-iii, b-i, c-ii, d-iv

Explanation: Correct answer is 1. LH triggers ovulation, FSH stimulates follicular growth, progesterone maintains endometrium post-ovulation, and estrogen peak induces LH surge for ovulation.

9. Fill in the Blanks MCQ:
_________ surge is essential for ovulation.
Options:
a. FSH
b. LH
c. Progesterone
d. Estrogen

Explanation: Correct answer is b. Luteinizing hormone surge from the anterior pituitary is the direct trigger for the rupture of the Graafian follicle and release of ovum during ovulation.

10. Choose the correct statements MCQ:
Select all correct statements:
i. Estrogen peak triggers LH surge
ii. LH surge causes ovulation
iii. Progesterone prepares endometrium post-ovulation
iv. Low FSH directly triggers ovulation
Options:
1. i, ii, iii
2. i, ii, iv
3. ii, iii, iv
4. i, iii, iv

Topic: Hormonal Regulation
Subtopic: Steroid Hormone Action

• Steroid Hormone: Lipid-soluble hormones derived from cholesterol that regulate gene expression.

• Gene-Hormone Complex: Formed when steroid hormones bind to DNA to modulate transcription of target genes.

• Cell Membrane: Biological membrane enclosing the cytoplasm, regulating substance exchange and signaling.

• Cyclic AMP (cAMP): Secondary messenger in peptide hormone signaling, activating protein kinases.

• Aquaporin Channels: Membrane proteins facilitating water transport across cell membranes.

• Transcription: Synthesis of RNA from DNA, influenced by steroid hormones in target cells.

• Endocrine System: Body system producing hormones regulating metabolism, growth, and reproduction.

• Receptor: Protein that binds hormones or ligands, triggering cellular response.

• Second Messenger: Intracellular signaling molecule transmitting extracellular signals from membrane receptors.

• Target Cell: Cell that responds to a specific hormone due to receptor presence.

• Hormonal Regulation: Control of cellular and physiological activities by hormones.

Lead Question (2019): How does steroid hormone influence the cellular activities?

Options:
1. Changing the permeability of the cell membrane.
2. Binding to DNA and forming a gene-hormone complex
3. Activating cyclic AMP located on the cell membrane.
4. Using aquaporin channels as second messenger

Explanation: Correct answer is 2. Steroid hormones are lipid-soluble and enter the cell, binding to specific intracellular receptors. This forms a gene-hormone complex, which directly influences transcription of target genes and protein synthesis. Unlike peptide hormones, they do not use membrane-bound cyclic AMP or aquaporin channels for signal transduction.

1. Single Correct Answer MCQ:
Which steroid hormone regulates calcium metabolism?
Options:
a. Cortisol
b. Aldosterone
c. Vitamin D (Calcitriol)
d. Insulin

Explanation: Correct answer is c. Calcitriol, the active form of vitamin D, is a steroid hormone regulating calcium and phosphate metabolism by binding intracellular receptors and modulating gene expression. Cortisol and aldosterone have other functions, while insulin is a peptide hormone affecting glucose metabolism.

2. Single Correct Answer MCQ:
Steroid hormones typically bind to receptors located in:
Options:
a. Cell membrane
b. Cytoplasm and nucleus
c. Golgi apparatus
d. Mitochondria

Explanation: Correct answer is b. Steroid hormones are lipid-soluble, so they diffuse through the plasma membrane and bind cytoplasmic or nuclear receptors to form gene-hormone complexes that regulate transcription. Membrane receptors and organelles like Golgi or mitochondria are not primary sites for steroid hormone binding.

3. Single Correct Answer MCQ:
Which of the following is a steroid hormone?
Options:
a. Insulin
b. Glucagon
c. Cortisol
d. Epinephrine

Explanation: Correct answer is c. Cortisol is a steroid hormone produced by the adrenal cortex, regulating metabolism and stress response. Insulin and glucagon are peptide hormones, and epinephrine is an amine hormone; none use intracellular receptors to modulate gene expression.

4. Single Correct Answer MCQ:
Steroid hormones influence target cells by:
Options:
a. Activating adenylate cyclase
b. Increasing cAMP levels
c. Directly regulating gene transcription
d. Opening ion channels

Explanation: Correct answer is c. Steroid hormones penetrate the cell membrane and form gene-hormone complexes, directly modulating transcription. Unlike peptide hormones, they do not activate adenylate cyclase, change cAMP, or open ion channels, making gene regulation their primary mechanism of action.

5. Single Correct Answer MCQ:
Which receptor type mediates steroid hormone action?
Options:
a. G-protein coupled receptor
b. Nuclear receptor
c. Tyrosine kinase receptor
d. Ion channel receptor

Explanation: Correct answer is b. Steroid hormones bind nuclear receptors in cytoplasm or nucleus, forming gene-hormone complexes that modulate transcription. G-protein coupled, tyrosine kinase, or ion channel receptors are used by peptide or amine hormones, not steroid hormones.

6. Single Correct Answer MCQ:
Which steroid hormone is involved in water and salt balance?
Options:
a. Aldosterone
b. Testosterone
c. Progesterone
d. Cortisol

Explanation: Correct answer is a. Aldosterone, a mineralocorticoid produced by adrenal cortex, regulates sodium and water reabsorption in kidneys by influencing gene transcription. Testosterone, progesterone, and cortisol have different functions in reproduction, metabolism, and stress response.

7. Assertion-Reason MCQ:
Assertion (A): Steroid hormones act by forming a gene-hormone complex.
Reason (R): They are lipid-soluble and enter the target cell to bind intracellular receptors.
Options:
a. Both A and R are true, R explains A
b. Both A and R are true, R does not explain A
c. A is true, R is false
d. A is false, R is true

Explanation: Correct answer is a. Steroid hormones are lipid-soluble, allowing them to penetrate the cell membrane and bind intracellular receptors. This leads to formation of gene-hormone complexes, which regulate transcription. Both assertion and reason are true, and the reason explains the mechanism described in the assertion.

8. Matching Type MCQ:
Match steroid hormones with their primary function:
Column-I Column-II
(a) Cortisol (i) Salt and water balance
(b) Aldosterone (ii) Stress and metabolism
(c) Testosterone (iii) Male reproductive functions
(d) Progesterone (iv) Female reproductive cycle
Options:
1. a-ii, b-i, c-iii, d-iv
2. a-i, b-ii, c-iv, d-iii
3. a-iii, b-iv, c-i, d-ii
4. a-iv, b-iii, c-ii, d-i

Explanation: Correct answer is 1. Cortisol regulates stress and metabolism, Aldosterone controls salt and water balance, Testosterone governs male reproductive functions, and Progesterone modulates female reproductive cycle. Matching hormones with their primary function demonstrates their role in physiological regulation.

9. Fill in the Blanks / Completion MCQ:</

Subtopic: Hormones and Related Diseases

Keyword Definitions:

• Insulin: Hormone produced by pancreatic beta cells that regulates blood glucose by promoting uptake into cells.

• Thyroxin: Thyroid hormone responsible for regulating metabolism, growth, and development.

• Corticoids: Hormones produced by adrenal cortex involved in stress response, metabolism, and electrolyte balance.

• Growth Hormone (GH): Pituitary hormone that stimulates growth, cell reproduction, and regeneration.

• Addison’s disease: Condition caused by adrenal insufficiency leading to cortisol deficiency.

• Diabetes insipidus: Disease due to ADH deficiency causing excessive urination and thirst.

• Acromegaly: Disorder due to excess growth hormone in adults, causing enlargement of bones and tissues.

• Goitre: Enlargement of thyroid gland due to iodine deficiency or thyroid hormone imbalance.

• Diabetes mellitus: Disease characterized by high blood sugar due to insulin deficiency or resistance.

Lead Question (2019):

Match the following hormones with the respective disease:
(a) Insulin (i) Addison’s disease
(b) Thyroxin (ii) Diabetes insipidus
(c) Corticoids (iii) Acromegaly
(d) Growth Hormone (iv) Goitre
(v) Diabetes mellitus

Explanation: Correct matches are a-v, b-iv, c-i, d-iii. Insulin deficiency causes Diabetes mellitus. Thyroxin imbalance results in Goitre. Corticoid deficiency leads to Addison’s disease. Excess Growth Hormone in adults results in Acromegaly. Understanding these hormone-disease relationships is key in physiology and clinical diagnosis.

1) Single Correct Answer MCQ:
Which hormone deficiency causes Diabetes mellitus?
(1) Thyroxin
(2) Corticoids
(3) Insulin
(4) Growth Hormone

Explanation: Correct answer is (3). Insulin deficiency or resistance prevents glucose uptake by cells, causing elevated blood glucose levels, which is the hallmark of Diabetes mellitus.

2) Single Correct Answer MCQ:
Goitre is caused by deficiency of:
(1) Corticoids
(2) Thyroxin
(3) Insulin
(4) Growth Hormone

Explanation: Correct answer is (2). Goitre results from deficiency of Thyroxin, which leads to thyroid enlargement as the gland attempts to compensate and produce sufficient hormone.

3) Single Correct Answer MCQ:
Addison’s disease is associated with deficiency of:
(1) Insulin
(2) Corticoids
(3) Thyroxin
(4) Growth Hormone

Explanation: Correct answer is (2). Addison’s disease arises due to adrenal cortex insufficiency, resulting in decreased production of Corticoids, which affects metabolism, stress response, and electrolyte balance.

4) Single Correct Answer MCQ:
Excess of which hormone leads to Acromegaly?
(1) Insulin
(2) Thyroxin
(3) Growth Hormone
(4) Corticoids

Explanation: Correct answer is (3). Excess Growth Hormone in adults causes Acromegaly, leading to abnormal enlargement of bones, hands, feet, and soft tissues.

5) Single Correct Answer MCQ:
Which hormone regulates blood sugar levels?
(1) Corticoids
(2) Thyroxin
(3) Insulin
(4) Growth Hormone

Explanation: Correct answer is (3). Insulin, secreted by pancreatic beta cells, facilitates cellular glucose uptake, lowering blood sugar and maintaining homeostasis.

6) Single Correct Answer MCQ:
Which hormone is secreted by the thyroid gland?
(1) Insulin
(2) Thyroxin
(3) Corticoids
(4) Growth Hormone

Explanation: Correct answer is (2). Thyroxin is produced by the thyroid gland and regulates metabolism, growth, and development. Deficiency can lead to Goitre.

7) Assertion-Reason MCQ:
Assertion (A): Excess growth hormone causes abnormal bone enlargement.
Reason (R): Growth Hormone stimulates cell growth and division.
Options:
(1) A true, R true, R correct explanation
(2) A true, R true, R not correct explanation
(3) A true, R false
(4) A false, R true

Explanation: Correct answer is (1). Excess GH stimulates continuous cell growth and division, leading to enlarged bones and tissues, as seen in Acromegaly.

8) Matching Type MCQ:
Match the hormone with the disease:
(a) Insulin - (i) Addison’s disease
(b) Thyroxin - (ii) Goitre
(c) Corticoids - (iii) Diabetes mellitus
(d) Growth Hormone - (iv) Acromegaly
Options:
(1) a-iii, b-ii, c-i, d-iv
(2) a-i, b-iii, c-ii, d-iv
(3) a-iii, b-i, c-iv, d-ii
(4) a-ii, b-iv, c-i, d-iii

Explanation: Correct answer is (1). Insulin deficiency causes Diabetes mellitus. Thyroxin deficiency leads to Goitre. Corticoid deficiency causes Addison’s disease. Excess Growth Hormone results in Acromegaly.

9) Fill in the Blanks MCQ:
The hormone responsible for regulating metabolism and produced by the thyroid gland is _______.
(1) Insulin
(2) Thyroxin
(3) Corticoids
(4) Growth Hormone

Explanation: Correct answer is (2). Thyroxin, secreted by the thyroid gland, controls basal metabolic rate, growth, and development. Its deficiency can result in Goitre.

10) Choose the correct statements MCQ:
(1) Insulin regulates blood glucose
(2) Corticoids deficiency causes Addison’s disease
(3) Thyroxin deficiency causes Goitre
(4) Excess Growth Hormone causes Acromegaly
Options:
(1) 1, 2, 3, 4
(2) 1, 2 and 4
(3) 2 and 3 only
(4) 1 and 3 only

Explanation: Correct answer is (1). All statements are correct. Insulin regulates glucose, Corticoid deficiency causes Addison’s disease, Thyroxin deficiency leads to Goitre, and excess Growth Hormone results in Acromegaly.

Topic: Endocrine System 

Subtopic: Amino Acid Derived Hormones 

Keyword Definitions:

• Hormones: Chemical messengers secreted by endocrine glands. 

• Amino Acid Derived Hormones: Hormones derived from tyrosine or tryptophan (e.g., epinephrine, thyroxine). 

• Steroid Hormones: Lipid-soluble hormones derived from cholesterol (e.g., estrogen, testosterone). 

• Peptide Hormones: Chains of amino acids (e.g., insulin, glucagon). 

• Endocrine Regulation: Control of body functions via hormones.

Lead Question - 2018

Which of the following is an amino acid derived hormone :

(A) Estriol

(B) Epinephrine

(C) Estradiol

(D) Ecdysone

Explanation: Epinephrine is an amino acid-derived hormone synthesized from tyrosine. Estriol and Estradiol are steroid hormones derived from cholesterol, while Ecdysone is a steroidal hormone in insects. Amino acid derived hormones act faster compared to steroid hormones. Hence, the correct answer is (B) Epinephrine. This distinction helps in understanding hormone classification.

1) Which of the following is a peptide hormone?

(A) Insulin

(B) Cortisol

(C) Estradiol

(D) Aldosterone

Explanation: Insulin is a peptide hormone secreted by pancreatic β-cells. It regulates glucose metabolism by promoting cellular glucose uptake. Cortisol, Estradiol, and Aldosterone are steroid hormones. Peptide hormones are hydrophilic and act via membrane receptors with second messenger systems. Thus, the correct answer is (A) Insulin, a classic peptide hormone.

2) Which hormone is iodine-dependent for its synthesis?

(A) Thyroxine

(B) Estrogen

(C) Cortisol

(D) Progesterone

Explanation: Thyroxine (T4) is an amino acid-derived hormone synthesized from tyrosine and requires iodine. It regulates basal metabolic rate and growth. Estrogen, Cortisol, and Progesterone are steroid hormones not requiring iodine. Deficiency of iodine leads to goiter. Thus, the correct answer is (A) Thyroxine, highlighting iodine’s role in hormone production.

3) Which of the following is secreted by adrenal medulla?

(A) Cortisol

(B) Epinephrine

(C) Aldosterone

(D) Testosterone

Explanation: Adrenal medulla secretes catecholamines like Epinephrine and Norepinephrine, which are amino acid-derived hormones from tyrosine. Cortisol and Aldosterone are secreted by adrenal cortex, while Testosterone comes from testes. Epinephrine mediates fight-or-flight response. Hence, the correct answer is (B) Epinephrine, showing the distinction between adrenal cortex and medulla functions.

4) A patient presents with hyperthyroidism. Which hormone will be elevated?

(A) Thyroxine

(B) Cortisol

(C) Insulin

(D) Prolactin

Explanation: Hyperthyroidism is characterized by excessive secretion of Thyroxine (T4). Thyroxine is an amino acid-derived hormone regulating metabolism, heart rate, and weight. Cortisol is a stress hormone, Insulin regulates glucose, and Prolactin regulates lactation. Hence, the correct answer is (A) Thyroxine, commonly elevated in Graves’ disease and other thyroid disorders.

5) Which of the following is NOT an amino acid derived hormone?

(A) Epinephrine

(B) Thyroxine

(C) Melatonin

(D) Estrogen

Explanation: Epinephrine (tyrosine), Thyroxine (tyrosine + iodine), and Melatonin (tryptophan) are amino acid-derived hormones. Estrogen, however, is a steroid hormone derived from cholesterol. Amino acid-derived hormones are usually water-soluble except thyroxine. Hence, the correct answer is (D) Estrogen, as it is not amino acid derived but steroidal.

6) Which hormone deficiency is linked to cretinism in children?

(A) Thyroxine

(B) Cortisol

(C) Estrogen

(D) Growth Hormone

Explanation: Deficiency of Thyroxine in early childhood causes cretinism, marked by stunted growth, intellectual disability, and developmental delay. Thyroxine is amino acid derived, requiring iodine. Cortisol and Estrogen are steroid hormones, while Growth Hormone is a peptide hormone. Correct answer is (A) Thyroxine, showing clinical relevance of amino acid-derived hormone deficiency.

7) Assertion-Reason Type:

Assertion: Epinephrine acts through second messengers.

Reason: It directly enters the nucleus to alter gene transcription.

(A) Both Assertion and Reason are true, Reason correctly explains Assertion

(B) Both Assertion and Reason are true, Reason does not explain Assertion

(C) Assertion true, Reason false

(D) Both Assertion and Reason false

Explanation: Epinephrine binds to cell membrane receptors and acts via second messengers like cAMP. It does not enter the nucleus directly, unlike steroid hormones. Hence, Assertion is true, but Reason is false. The correct answer is (C). This highlights different mechanisms of action between amino acid-derived and steroid hormones.

8) Matching Type:

Match the hormones with their origin:

(A) Melatonin - 1. Pineal gland

(B) Epinephrine - 2. Adrenal medulla

(C) Insulin - 3. Pancreas

(D) Cortisol - 4. Adrenal cortex

Options: (A) A-1, B-2, C-3, D-4

(B) A-2, B-1, C-3, D-4

(C) A-1, B-3, C-2, D-4

(D) A-4, B-2, C-1, D-3

Explanation: Melatonin is secreted by Pineal gland, Epinephrine by Adrenal medulla, Insulin by Pancreatic β-cells, and Cortisol by Adrenal cortex. Thus, the correct answer is (A) A-1, B-2, C-3, D-4. Matching type helps consolidate knowledge of endocrine organs and their hormone products.

9) Fill in the Blanks:

________ is an amino acid-derived hormone that regulates sleep-wake cycles.

(A) Melatonin

(B) Progesterone

(C) Cortisol

(D) Aldosterone

Explanation: Melatonin, derived from tryptophan, is secreted by the pineal gland and regulates circadian rhythms, especially sleep-wake cycles. Progesterone and Aldosterone are steroid hormones, while Cortisol regulates stress. Thus, the correct answer is (A) Melatonin, which is clinically important in managing sleep disorders and jet lag problems.

10) Choose the Correct Statements:

1. Thyroxine requires iodine for synthesis.

2. Epinephrine is derived from cholesterol.

3. Melatonin is secreted by pineal gland.

4. Estrogen is amino acid derived.

Options:

(A) 1 and 3 only

(B) 2 and 4 only

(C) 1, 2 and 3 only

(D) 1, 3 and 4 only

Explanation: Thyroxine synthesis requires iodine (true). Epinephrine is derived from tyrosine, not cholesterol (false). Melatonin is secreted by pineal gland (true). Estrogen is steroid, not amino acid derived (false). Correct answer is (A) 1 and 3 only. This question reinforces distinctions between steroid and amino acid-derived hormones.

Topic: Endocrine System

Subtopic: Hormonal Regulation of Bone Health

Keyword Definitions:

Osteoporosis: A condition of reduced bone mass leading to fragile bones.

Parathyroid Hormone (PTH): Hormone that increases blood calcium by bone resorption.

Prolactin: Hormone stimulating milk production; excess may affect calcium metabolism.

Aldosterone: Hormone regulating sodium and water balance.

Estrogen: Female sex hormone that protects bone density.

Progesterone: Hormone supporting pregnancy, with minor effects on bones.

Bone Resorption: Process by which osteoclasts break down bone tissue.

Calcium Homeostasis: Balance of calcium levels in blood and bone.

Hormonal Imbalance: Disruption of hormone levels affecting health.

Clinical Significance: Hormone-related disorders can directly contribute to osteoporosis.

Lead Question - 2018

Which of the following hormones can play a significant role in osteoporosis:

(A) Parathyroid hormone and Prolactin

(B) Aldosterone and Prolactin

(C) Estrogen and Parathyroid hormone

(D) Progesterone and Aldosterone

Explanation: Osteoporosis results from low estrogen (post-menopause) and excessive parathyroid hormone, both promoting bone resorption and reducing bone mass. Prolactin and aldosterone play minor or no role in bone fragility. Correct answer: C.

1. MCQ - Single Correct Answer

Deficiency of which hormone commonly leads to postmenopausal osteoporosis?

(a) Estrogen

(b) Progesterone

(c) Cortisol

(d) Thyroxine

Explanation: Estrogen deficiency

2. MCQ - Single Correct Answer

Excess secretion of parathyroid hormone causes:

(a) Hypocalcemia

(b) Hypercalcemia

(c) Hyponatremia

(d) Hyperkalemia

Explanation: Excess PTH

3. MCQ - Single Correct Answer (Clinical)

A 55-year-old woman presents with back pain and fragile bones. Which hormone deficiency is most likely?

(a) Estrogen

(b) Progesterone

(c) Insulin

(d) Cortisol

Explanation: The most common cause of postmenopausal osteoporosis is estrogen deficiency, leading to increased bone resorption and fragility fractures. Correct answer: a.

4. MCQ - Single Correct Answer

Which cells are responsible for bone resorption in osteoporosis?

(a) Osteoblasts

(b) Osteocytes

(c) Osteoclasts

(d) Chondrocytes

Explanation: Osteoclasts are bone-resorbing cells stimulated by PTH and lack of estrogen, leading to osteoporosis. Osteoblasts form bone, while osteocytes maintain it. Correct answer: c.

5. MCQ - Single Correct Answer

Increased risk of osteoporosis is associated with deficiency of:

(a) Vitamin D

(b) Vitamin C

(c) Vitamin K

(d) Vitamin E

Explanation: Vitamin D deficiency

6. MCQ - Single Correct Answer (Clinical)

A patient with hyperparathyroidism shows recurrent fractures. The mechanism is:

(a) Excess calcium deposition in bone

(b) Increased bone resorption

(c) Decreased osteoclast activity

(d) Increased bone formation

Explanation: Excess PTH

7. MCQ - Assertion-Reason

Assertion (A): Estrogen protects against osteoporosis.

Reason (R): Estrogen suppresses osteoclast activity and promotes osteoblast survival.

(a) Both A and R true, R correct explanation

(b) Both A and R true, R not correct explanation

(c) A true, R false

(d) A false, R true

Explanation: Estrogen deficiency increases osteoclast activity, leading to bone loss. The reason explains the assertion correctly. Correct answer: a.

8. MCQ - Matching Type

Match hormone with its role in bone metabolism:

1. Estrogen - (a) Promotes osteoblast survival

2. PTH - (b) Stimulates bone resorption

3. Calcitonin - (c) Inhibits osteoclast activity

4. Vitamin D - (d) Enhances calcium absorption

Options:

(A) 1-a, 2-b, 3-c, 4-d

(B) 1-b, 2-c, 3-d, 4-a

(C) 1-d, 2-a, 3-b, 4-c

(D) 1-c, 2-d, 3-a, 4-b

Explanation: Correct matches: Estrogen–a, PTH–b, Calcitonin–c, Vitamin D–d. Correct answer: A.

9. MCQ - Fill in the Blanks

__________ deficiency after menopause is a major cause of osteoporosis.

(a) Estrogen

(b) Insulin

(c) Cortisol

(d) Thyroxine

Explanation: Estrogen deficiency

10. MCQ - Choose Correct Statements

Which statements about osteoporosis are correct?

1. Estrogen protects bone health

2. PTH excess promotes bone resorption

3. Aldosterone deficiency causes osteoporosis

4. Vitamin D improves calcium absorption

Options:

(A) 1, 2, 4

(B) 2, 3

(C) 1 and 3

(D) All 1,2,3,4

Explanation: Statements 1, 2, and 4 are correct: Estrogen protects bones, PTH excess resorbs bone, Vitamin D improves absorption. Aldosterone is unrelated to osteoporosis. Correct answer: A. 

Subtopic: Endocrine Regulation of Blood Pressure

Keyword Definitions:

Blood Pressure: Force exerted by circulating blood on vessel walls.

Blood Volume: Total amount of blood in the circulatory system.

ADH (Antidiuretic Hormone): Hormone secreted by posterior pituitary to conserve water.

Renin: Enzyme from kidney that regulates blood pressure via RAAS.

Aldosterone: Hormone from adrenal cortex that increases sodium reabsorption.

Atrial Natriuretic Factor (ANF): Hormone released by atria in response to increased blood volume, reduces BP.

RAAS: Renin-Angiotensin-Aldosterone System regulating blood pressure and fluid balance.

Clinical Significance: Dysregulation of these hormones can cause hypertension, hypotension, or edema.

Homeostasis: Maintenance of stable internal conditions including blood pressure.

Kidney Function: Regulates electrolyte balance, volume, and hormone secretion.

Cardiovascular Response: Hormonal adjustments maintain circulation under stress or volume changes.

Lead Question - 2017

A decrease in blood pressure / volume will not cause the release of:

(A) ADH

(B) Renin

(C) Atrial Natriuretic Factor

(D) Aldosterone

Explanation: A decrease in blood pressure or volume stimulates ADH, Renin, and Aldosterone to conserve water and sodium. Atrial Natriuretic Factor (ANF) is released when atrial pressure rises; it lowers BP. Thus, decreased BP does not trigger ANF secretion. Correct answer: C.

1. MCQ - Single Correct Answer

ADH primarily acts on:

(a) Liver

(b) Kidneys

(c) Lungs

(d) Heart

Explanation: ADH acts on kidney collecting ducts to increase water reabsorption, maintaining blood volume and pressure. Liver, lungs, and heart are not direct targets. Proper ADH secretion prevents hypotension and dehydration. Correct answer: b.

2. MCQ - Single Correct Answer

Renin release is triggered by:

(a) High blood pressure

(b) Low blood pressure

(c) High blood volume

(d) High sodium intake

Explanation: Renin is secreted by juxtaglomerular cells when blood pressure drops. It initiates RAAS to increase angiotensin II and aldosterone, raising BP. High blood pressure, volume, or sodium inhibits renin. Correct answer: b.

3. MCQ - Single Correct Answer (Clinical)

Hyperaldosteronism may cause:

(a) Hypotension

(b) Hypertension

(c) Low sodium loss

(d) Dehydration

Explanation: Excess aldosterone increases sodium retention and water reabsorption, raising blood volume and causing hypertension. Hypotension occurs with aldosterone deficiency. Correct answer: b.

4. MCQ - Single Correct Answer

ANF is released from:

(a) Kidneys

(b) Adrenal cortex

(c) Cardiac atria

(d) Pituitary gland

Explanation: Atrial Natriuretic Factor is secreted by cardiac atria in response to increased blood volume. It promotes sodium excretion and reduces blood pressure. Kidneys, adrenal cortex, and pituitary are not sources. Correct answer: c.

5. MCQ - Single Correct Answer

Which hormone decreases blood pressure?

(a) ADH

(b) Aldosterone

(c) ANF

(d) Renin

Explanation: ANF lowers blood pressure by promoting sodium and water excretion. ADH, Aldosterone, and Renin work to raise blood pressure. Proper ANF release prevents volume overload and hypertension. Correct answer: c.

6. MCQ - Single Correct Answer (Clinical)

A patient with hypovolemia will have elevated levels of:

(a) ANF

(b) ADH

(c) Both a and b

(d) None

Explanation: In hypovolemia, blood volume is low. The body increases ADH to conserve water. ANF is not released as atrial stretch is reduced. Correct answer: b.

7. MCQ - Assertion-Reason

Assertion (A): ANF secretion increases with high blood volume.

Reason (R): ANF promotes sodium and water excretion.

(a) Both A and R true, R correct explanation

(b) Both A and R true, R not correct explanation

(c) A true, R false

(d) A false, R true

Explanation: ANF is released when atrial pressure rises, promoting sodium and water excretion to lower blood volume and pressure. Both assertion and reason are true, and the reason correctly explains the assertion. Correct answer: a.

8. MCQ - Matching Type

Match hormone with function:

1. ADH - (a) Sodium excretion

2. Renin - (b) Initiates RAAS

3. ANF - (c) Water reabsorption

4. Aldosterone - (d) Sodium retention

Options:

(A) 1-c, 2-b, 3-a, 4-d

(B) 1-b, 2-c, 3-d, 4-a

(C) 1-a, 2-b, 3-c, 4-d

(D) 1-d, 2-c, 3-b, 4-a

Explanation: ADH: water reabsorption; Renin: initiates RAAS; ANF: sodium excretion; Aldosterone: sodium retention. Correct matching: 1-c, 2-b, 3-a, 4-d. Answer: A.

9. MCQ - Fill in the Blanks

_________ increases sodium and water reabsorption to raise blood pressure.

(a) ANF

(b) Aldosterone

(c) ADH

(d) Renin

Explanation: Aldosterone from adrenal cortex promotes sodium and water retention in kidneys, increasing blood volume and pressure. ANF reduces BP, ADH only conserves water, and renin indirectly raises BP via RAAS. Correct answer: b.

10. MCQ - Choose Correct Statements

Select correct statements about blood pressure regulation:

1. Decreased BP stimulates ADH release

2. ANF is released during low blood volume

3. Renin increases BP via RAAS

4. Aldosterone promotes sodium retention

Options:

(A) 1, 3, and 4

(B) 1 and 2

(C) 2 and 4

(D) All 1,2,3,4

Explanation: Low BP triggers ADH and renin release; aldosterone promotes sodium retention. ANF is secreted when blood volume is high, not low. Correct statements: 1, 3, and 4. Answer: A. 

Subtopic: Endocrine System

Keyword Definitions:

Endocrine Gland: Gland that secretes hormones directly into the blood.

Corpus Luteum: Temporary gland formed after ovulation in females.

Pineal Gland: Small gland in the brain secreting melatonin.

Corpus Allatum: In insects, secretes juvenile hormone.

Corpus Cardiacum: In insects, stores and releases hormones.

Hormone: Chemical messenger regulating physiological processes.

Ovulation: Release of mature egg from ovary.

Progesterone: Hormone secreted by corpus luteum supporting pregnancy.

Temporary Gland: Endocrine gland that exists only for a short period.

Clinical Significance: Corpus luteum disorders can cause infertility or menstrual irregularities.

Exocrine vs Endocrine: Exocrine glands release secretions through ducts, endocrine glands release directly into blood.

Lead Question - 2017

A temporary endocrine gland in the human body is:

(A) Corpus allatum

(B) Pineal gland

(C) Corpus cardiacum

(D) Corpus luteum

Explanation: The corpus luteum forms in the ovary after ovulation and secretes progesterone to support early pregnancy. It degenerates if fertilization does not occur, making it a temporary endocrine gland. Therefore, correct answer is D.

1. MCQ - Single Correct Answer

Which hormone is primarily secreted by the corpus luteum?

(a) Estrogen

(b) Progesterone

(c) Testosterone

(d) Melatonin

Explanation: The corpus luteum secretes progesterone after ovulation, which maintains the uterine lining for potential pregnancy. Estrogen is secreted earlier by the follicle, testosterone by testes, and melatonin by pineal gland. Answer: b.

2. MCQ - Single Correct Answer

The pineal gland regulates:

(a) Blood glucose

(b) Sleep-wake cycle

(c) Blood pressure

(d) Ovulation

Explanation: The pineal gland secretes melatonin, controlling circadian rhythms and sleep-wake cycle. It is permanent, unlike corpus luteum. Blood glucose is regulated by pancreas, blood pressure by adrenal hormones, and ovulation by ovarian hormones. Answer: b.

3. MCQ - Single Correct Answer (Clinical)

Absence or malfunction of corpus luteum can lead to:

(a) Diabetes

(b) Infertility

(c) Hypertension

(d) Hyperthyroidism

Explanation: Dysfunctional corpus luteum leads to insufficient progesterone, causing luteal phase defects, irregular cycles, or infertility. Proper corpus luteum function is critical for early pregnancy maintenance. Answer: b.

4. MCQ - Single Correct Answer

Corpus allatum is found in:

(a) Humans

(b) Insects

(c) Birds

(d) Fish

Explanation: Corpus allatum is an endocrine gland in insects secreting juvenile hormone, regulating development and metamorphosis. It is not present in humans. Answer: b.

5. MCQ - Single Correct Answer

Which gland is responsible for secreting juvenile hormone in insects?

(a) Corpus luteum

(b) Corpus cardiacum

(c) Corpus allatum

(d) Pineal gland

Explanation: The corpus allatum in insects produces juvenile hormone, controlling larval development and preventing premature metamorphosis. Corpus luteum and pineal gland are in vertebrates, corpus cardiacum stores hormones. Answer: c.

6. MCQ - Single Correct Answer (Clinical)

Progesterone deficiency during early pregnancy may result in:

(a) Miscarriage

(b) Hyperthyroidism

(c) Infertility only

(d) Hypertension

Explanation: Low progesterone from corpus luteum during early pregnancy can fail to maintain uterine lining, causing miscarriage. Supplementation may be clinically necessary in luteal phase defects. Answer: a.

7. MCQ - Assertion-Reason

Assertion (A): Corpus luteum is temporary.

Reason (R): It forms after ovulation and degenerates if pregnancy does not occur.

(a) Both A and R true, R correct explanation

(b) Both A and R true, R not correct explanation

(c) A true, R false

(d) A false, R true

Explanation: Corpus luteum forms post-ovulation and secretes progesterone. If fertilization fails, it degenerates, confirming its temporary nature. Both assertion and reason are correct, with reason explaining assertion. Answer: a.

8. MCQ - Matching Type

Match gland with its function:

1. Corpus luteum - (a) Melatonin secretion

2. Pineal gland - (b) Progesterone secretion

3. Corpus cardiacum - (c) Hormone storage in insects

Options:

(A) 1-b, 2-a, 3-c

(B) 1-c, 2-b, 3-a

(C) 1-a, 2-c, 3-b

(D) 1-b, 2-c, 3-a

Explanation: Corpus luteum secretes progesterone, pineal gland secretes melatonin, and corpus cardiacum stores insect hormones. Correct matching: 1-b, 2-a, 3-c. Answer: A.

9. MCQ - Fill in the Blanks

The corpus luteum forms from the __________ after ovulation.

(a) Follicle

(b) Ovary wall

(c) Pineal gland

(d) Corpus cardiacum

Explanation: After ovulation, the ruptured follicle transforms into corpus luteum, which secretes progesterone to prepare endometrium for possible pregnancy. If fertilization does not occur, it degenerates. Answer: a.

10. MCQ - Choose Correct Statements

Select correct statements about corpus luteum:

1. Temporary endocrine gland

2. Secretes estrogen only

3. Forms from follicle after ovulation

4. Degenerates if pregnancy does not occur

Options:

(A) 1, 3, and 4

(B) 2 and 3

(C) 1 and 2 only

(D) All 1,2,3,4

Explanation: Corpus luteum is temporary, forms after ovulation from follicle, and degenerates if no pregnancy occurs. It secretes progesterone, not estrogen only. Correct statements: 1, 3, and 4. Answer: A. 

Topic: Endocrine System

Subtopic: Growth Hormone Disorders

Keyword Definitions:

• Growth Hormone (GH) – Hormone secreted by anterior pituitary regulating growth and metabolism.

• Hypersecretion – Excessive secretion of a hormone beyond normal physiological levels.

• Epiphyseal plates – Cartilaginous growth regions at the ends of long bones.

• Adults – Human post-adolescent stage where growth plates are fused.

• Acromegaly – Condition in adults due to GH excess causing bone thickening.

• Gigantism – Condition in children due to GH excess causing abnormal height.

• Muscle fibers – Basic units of skeletal muscle responsible for contraction.

• Pituitary gland – Endocrine gland regulating various hormones including GH.

• Bone growth – Increase in bone length primarily during childhood and adolescence.

• Hormone sensitivity – Ability of tissues to respond to hormonal signals.

• Anterior pituitary – Front portion of pituitary gland secreting GH, TSH, ACTH, etc.

Lead Question – 2017:

Hypersecretion of Growth Hormone in adults does not cause further increase in height because:

(A) Muscle fibres do not grow in size after birth

(B) Growth Hormone becomes inactive in adults

(C) Epiphyseal plates close after adolescence

(D) Bones lose their sensitivity to Growth Hormone in adults

Explanation:

Correct option is C (Epiphyseal plates close after adolescence). In adults, the epiphyseal growth plates are fused, preventing further elongation of long bones. Hypersecretion of GH in adults causes acromegaly, leading to bone thickening, organ enlargement, and soft tissue growth, but not increase in height. (Answer: C)

1) Single Correct Answer MCQ:

Excess GH secretion in children before epiphyseal plate closure leads to:

(A) Acromegaly

(B) Gigantism

(C) Dwarfism

(D) Osteoporosis

Explanation:

Hypersecretion of GH before closure of epiphyseal plates causes Gigantism, characterized by excessive height due to elongation of long bones. Acromegaly occurs after epiphyseal closure in adults. (Answer: B)

2) Single Correct Answer MCQ:

Acromegaly is characterized by:

(A) Increased height

(B) Enlargement of hands, feet, and facial bones

(C) Muscle atrophy

(D) Epiphyseal plate elongation

Explanation:

In adults, hypersecretion of GH leads to Acromegaly, causing thickening of bones in hands, feet, and face. Height does not increase due to closed epiphyseal plates, but bones and soft tissues enlarge. (Answer: B)

3) Single Correct Answer MCQ:

Which gland secretes Growth Hormone?

(A) Thyroid

(B) Adrenal

(C) Anterior pituitary

(D) Pancreas

Explanation:

Growth Hormone is secreted by the anterior pituitary. It regulates bone and tissue growth, metabolism, and protein synthesis. Pituitary tumors can cause hypersecretion or hyposecretion disorders. (Answer: C)

4) Single Correct Answer MCQ:

What is the main clinical feature of GH deficiency in adults?

(A) Increased height

(B) Reduced muscle mass and bone density

(C) Enlarged facial bones

(D) Excess sweating

Explanation:

GH deficiency in adults leads to reduced muscle mass and bone density, decreased energy, and altered body composition. Height is unaffected because epiphyseal plates are already closed. (Answer: B)

5) Single Correct Answer MCQ:

Which hormone primarily stimulates epiphyseal plate activity in children?

(A) Cortisol

(B) Thyroxine

(C) Growth Hormone

(D) Insulin

Explanation:

< b>Growth Hormone

stimulates cartilage proliferation in epiphyseal plates during childhood and adolescence, promoting linear bone growth. After plate closure, GH cannot increase height. (Answer: C)

6) Single Correct Answer MCQ:

What complication can arise in adults due to GH hypersecretion?

(A) Dwarfism

(B) Acromegaly

(C) Osteogenesis imperfecta

(D) Marfan syndrome

Explanation:

GH hypersecretion in adults results in Acromegaly, characterized by enlarged extremities, facial bones, and organ growth, but no height increase due to closed epiphyseal plates. (Answer: B)

7) Assertion-Reason MCQ:

Assertion (A): Adults with GH hypersecretion do not grow taller.

Reason (R): Epiphyseal plates are fused after adolescence.

(A) Both A and R true, R explains A

(B) Both A and R true, R does not explain A

(C) A true, R false

(D) A false, R true

Explanation:

Both A and R are true. Height cannot increase in adults because epiphyseal plates are closed; GH can still cause soft tissue and bone thickening. (Answer: A)

8) Matching Type MCQ:

Match:

1. GH excess before adolescence – (i) Gigantism

2. GH excess after adolescence – (ii) Acromegaly

3. GH deficiency in children – (iii) Dwarfism

Options:

(A) 1-i, 2-ii, 3-iii

(B) 1-ii, 2-i, 3-iii

(C) 1-iii, 2-i, 3-ii

(D) 1-i, 2-iii, 3-ii

Explanation:

Correct matching: 1-i (Gigantism), 2-ii (Acromegaly), 3-iii (Dwarfism). Timing of GH excess or deficiency determines clinical outcomes. (Answer: A)

9) Fill in the Blanks MCQ:

Epiphyseal plates close during _______ marking the end of height increase.

(A) Childhood

(B) Adolescence

(C) Adulthood

(D) Infancy

Explanation:

Epiphyseal plates fuse during adolescence, preventing further longitudinal bone growth. GH excess in adults affects bone thickness, not height. (Answer: B)

10) Choose the correct statements MCQ:

1. GH hypersecretion in adults causes acromegaly.

2. GH excess in children can cause gigantism.

3. Epiphyseal plate closure prevents height increase in adults.

4. Muscle fibers do not respond to GH after birth.

Options:

(A) 1, 2, 3

(B) 1, 3, 4

(C) 2, 3, 4

(D) 1, 2, 4

Explanation:

Statements 1, 2, 3 are correct. GH hypersecretion effects depend on epiphyseal plate status: gigantism in children, acromegaly in adults. Muscle fibers can hypertrophy but height increase is limited by fused plates. (Answer: A)

Topic: Hormonal Regulation
Subtopic: Hypothalamic-Pituitary-Gonadal Axis

Keyword Definitions:

• GnRH: Gonadotropin-releasing hormone secreted by hypothalamus that regulates reproductive hormones.

• Anterior pituitary: Gland that releases hormones like LH and FSH under GnRH influence.

• LH: Luteinizing hormone essential for ovulation and testosterone production.

• FSH: Follicle-stimulating hormone that regulates gamete maturation.

• Posterior pituitary: Stores and releases oxytocin and vasopressin but not controlled by GnRH.

Lead Question - 2017

GnRH, a hypothalamic hormone, needed in reproduction acts on :
(A) Posterior pituitary gland and stimulates secretion of LH and relaxin
(B) Anterior pituitary gland and stimulates secretion of LH and oxytocin
(C) Anterior pituitary gland and stimulates secretion of LH and FSH
(D) Posterior pituitary gland and stimulates secretion of oxytocin and FSH

Explanation: GnRH is released from hypothalamus in a pulsatile manner. It stimulates anterior pituitary to secrete LH and FSH, which regulate ovarian and testicular functions. Posterior pituitary stores oxytocin and vasopressin but not influenced by GnRH. Correct answer is (C) Anterior pituitary gland and stimulates secretion of LH and FSH.

1) Which hormone triggers ovulation in females?
(A) FSH
(B) LH
(C) Prolactin
(D) Oxytocin

Explanation: Ovulation is triggered by a surge in LH, which ruptures the mature Graafian follicle releasing the ovum. FSH supports follicle growth but LH peak initiates ovulation. Prolactin regulates lactation and oxytocin helps in parturition. Correct answer is (B) LH.

2) Clinical Type: A male patient with low sperm count is tested and found to have deficient FSH secretion. Which structure is mainly affected?
(A) Sertoli cells
(B) Leydig cells
(C) Hypothalamus
(D) Epididymis

Explanation: FSH acts on Sertoli cells to stimulate spermatogenesis. Deficiency of FSH results in impaired support of germ cells, reducing sperm production. Leydig cells are regulated by LH for testosterone secretion. Thus, primary defect is in (A) Sertoli cells.

3) In females, corpus luteum secretes:
(A) Progesterone
(B) Estrogen only
(C) FSH
(D) LH

Explanation: After ovulation, corpus luteum forms and secretes progesterone, essential for maintaining endometrium for implantation. It also secretes some estrogen. LH and FSH are pituitary hormones, not secreted by corpus luteum. Correct answer is (A) Progesterone.

4) Assertion-Reason Type:
Assertion (A): GnRH is secreted in a pulsatile manner.
Reason (R): Continuous secretion of GnRH leads to down-regulation of its receptors on anterior pituitary.
(A) Both A and R true, R is correct explanation
(B) Both A and R true, R is not correct explanation
(C) A true, R false
(D) A false, R true

Explanation: Pulsatile GnRH secretion maintains receptor sensitivity. Continuous secretion causes receptor desensitization and reduced LH/FSH secretion. Both statements are true and the reason explains assertion. Correct answer is (A).

5) Match the following:
Column I
(a) GnRH
(b) LH
(c) FSH
(d) Prolactin
Column II
1. Stimulates Leydig cells
2. Stimulates Sertoli cells
3. Stimulates mammary glands
4. Stimulates anterior pituitary
Options:
(A) a-4, b-1, c-2, d-3
(B) a-2, b-3, c-1, d-4
(C) a-3, b-2, c-4, d-1
(D) a-1, b-4, c-2, d-3

Explanation: GnRH stimulates anterior pituitary (4), LH acts on Leydig cells (1), FSH stimulates Sertoli cells (2), and prolactin stimulates mammary glands (3). Correct answer is (A).

6) Fill in the blank: In males, LH acts on ______ cells to stimulate testosterone production.
(A) Sertoli
(B) Leydig
(C) Spermatogonia
(D) Epididymal

Explanation: LH targets Leydig cells in testes to stimulate testosterone synthesis, which is crucial for spermatogenesis and secondary sexual characters. Sertoli cells are FSH-dependent, spermatogonia form sperm, and epididymis stores sperm. Correct answer is (B) Leydig.

7) Which hormone is secreted by placenta during pregnancy?
(A) HCG
(B) LH
(C) FSH
(D) Oxytocin

Explanation: Placenta secretes human chorionic gonadotropin (HCG), which maintains corpus luteum for progesterone secretion during early pregnancy. LH and FSH are pituitary hormones, oxytocin is from posterior pituitary. Correct answer is (A) HCG.

8) Clinical Type: A woman undergoing infertility treatment is given GnRH agonists in a pulsatile manner. What is the effect?
(A) Decreased gonadotropins
(B) Increased LH and FSH
(C) Increased prolactin
(D) Increased oxytocin

Explanation: Pulsatile GnRH agonists mimic physiological release, enhancing anterior pituitary secretion of LH and FSH. This supports ovulation induction and fertility treatment. Correct answer is (B) Increased LH and FSH.

9) Choose the correct statements:
(i) GnRH is secreted by hypothalamus.
(ii) LH stimulates testosterone in males.
(iii) FSH stimulates oogenesis.
(iv) Prolactin causes milk ejection.
Options:
(A) i, ii, iii
(B) i, ii, iv
(C) ii, iii, iv
(D) i, ii, iii, iv

Explanation: Statements (i), (ii), and (iii) are correct. Prolactin promotes milk production, but milk ejection is caused by oxytocin. Hence statement (iv) is incorrect. Correct answer is (A).

10) Which hormone is responsible for uterine contractions during parturition?
(A) LH
(B) Oxytocin
(C) FSH
(D) Progesterone

Explanation: Oxytocin secreted from posterior pituitary stimulates strong uterine contractions during labor and also causes milk let-down reflex. LH and FSH regulate gonads, progesterone maintains pregnancy but does not initiate contractions. Correct answer is (B) Oxytocin.

Topic: Endocrine System
Subtopic: Posterior Pituitary Gland

• Posterior Pituitary: Part of the pituitary gland that stores and releases hormones made by hypothalamus.

• Endocrine Gland: Glands that secrete hormones directly into the blood.

• Hypothalamus: Brain region controlling pituitary hormone release and maintaining homeostasis.

• Oxytocin: Hormone secreted by posterior pituitary controlling uterine contractions and milk ejection.

• ADH (Vasopressin): Hormone regulating water balance, released by posterior pituitary.

• Ductless: Characteristic of endocrine glands that release hormones directly into the bloodstream.

• Clinical Relevance: Disorders include diabetes insipidus and pituitary dysfunction affecting ADH and oxytocin secretion.

Lead Question - 2016 (Phase 2): The posterior pituitary gland is not a ‘true’ endocrine gland because :

1. it secretes enzymes

2. it is provided with a duct

3. it only stores and releases hormones

4. it is under the regulation of hypothalamus

Explanation: The correct answer is (3). The posterior pituitary is not a true endocrine gland because it does not synthesize hormones; it only stores and releases hormones produced by the hypothalamus, such as ADH and oxytocin. Clinically, dysfunction can cause diabetes insipidus or impaired lactation.

Chapter: Human Physiology
Topic: Endocrine System
Subtopic: Posterior Pituitary Gland

• Posterior Pituitary: Stores and releases hypothalamic hormones.

• Oxytocin: Stimulates uterine contractions and milk ejection.

• ADH: Regulates water balance in kidneys.

• Hypothalamus: Controls hormone release from pituitary.

• Endocrine Gland: Secretes hormones directly into blood.

1. Which hormone is synthesized in the posterior pituitary?

1. Oxytocin

2. ADH

3. Both A and B

4. Neither A nor B

Explanation: The correct answer is (4). The posterior pituitary does not synthesize hormones; it only stores and releases oxytocin and ADH, which are produced in the hypothalamus. Clinically, failure to release these hormones can lead to diabetes insipidus or lactation defects.

2. The hypothalamic hormone that stimulates ADH release is:

1. TRH

2. CRH

3. Oxytocin

4. None of the above

Explanation: The correct answer is (4). ADH is synthesized in hypothalamic nuclei (supraoptic and paraventricular) and released by posterior pituitary. TRH and CRH regulate anterior pituitary hormones. Clinical relevance includes disorders like diabetes insipidus caused by deficient ADH release.

3. Oxytocin plays a key role in:

1. Water balance

2. Blood sugar regulation

3. Uterine contraction and milk ejection

4. Thyroid hormone release

Explanation: The correct answer is (3). Oxytocin, stored in the posterior pituitary, induces uterine contractions during labor and milk ejection during lactation. Clinical importance is in managing labor or breastfeeding complications related to inadequate oxytocin release.

4. Which condition arises due to insufficient ADH?

1. Diabetes mellitus

2. Diabetes insipidus

3. Hyperthyroidism

4. Cushing’s syndrome

Explanation: The correct answer is (2). Insufficient ADH secretion or release leads to diabetes insipidus, characterized by polyuria and polydipsia. This clinical condition highlights the posterior pituitary’s functional role in water homeostasis, despite not being a true endocrine gland.

5. Which statement is true about posterior pituitary?

1. It synthesizes hormones

2. It has ducts

3. It stores hypothalamic hormones

4. It regulates anterior pituitary

Explanation: The correct answer is (3). The posterior pituitary stores hormones made by hypothalamus, such as ADH and oxytocin. It does not synthesize hormones nor have ducts. Clinically, storage and release disorders affect fluid balance or lactation.

6. Which nuclei of hypothalamus produce ADH?

1. Supraoptic and paraventricular nuclei

2. Ventromedial nucleus

3. Arcuate nucleus

4. Posterior nucleus

Explanation: The correct answer is (1). ADH is synthesized in supraoptic and paraventricular nuclei of hypothalamus and stored in posterior pituitary. Clinical dysfunction causes diabetes insipidus, showing the importance of hypothalamic-posterior pituitary axis.

7. Assertion (A): Posterior pituitary is not a true endocrine gland.
Reason (R): It stores but does not synthesize hormones.

1. A is true, R is true, R explains A

2. A is true, R is true, R does not explain A

3. A is true, R is false

4. A is false, R is true

Explanation: The correct answer is (1). Posterior pituitary only stores and releases hypothalamic hormones like ADH and oxytocin, not synthesizing them. This explains why it is not a true endocrine gland. Clinically, this distinction is important for understanding endocrine disorders affecting fluid balance and lactation.

8. Match the hormones with their function:

1. ADH

2. Oxytocin

A. Stimulates uterine contractions and milk ejection
B. Regulates water reabsorption in kidneys

Explanation: Correct matching: 1-B, 2-A. ADH regulates water balance, oxytocin controls uterine contractions and lactation. Clinically, understanding these hormone functions is critical for diagnosing and managing disorders like diabetes insipidus and lactation failure.

9. Fill in the blank: Hormones stored in the posterior pituitary are synthesized in the ______.

1. Anterior pituitary

2. Hypothalamus

3. Thyroid gland

4. Pancreas

Explanation: The correct answer is (2). Hormones like ADH and oxytocin are synthesized in hypothalamic nuclei and stored in posterior pituitary. Clinical significance includes disorders like diabetes insipidus, where inadequate release of ADH affects fluid balance.

10. Choose correct statements about posterior pituitary:

1. It stores hypothalamic hormones

2. It synthesizes ADH and oxytocin

3. It releases hormones into blood

4. It has no duct

Explanation: The correct answers are (1,3,4). Posterior pituitary stores hypothalamic hormones, releases them into blood, and has no duct. It does not synthesize hormones. Clinically, this understanding is crucial in managing disorders like diabetes insipidus and lactation abnormalities.

Topic: Endocrine Hormones

Subtopic: Insulin and Glucose Metabolism

Keyword Definitions

• Insulin: A peptide hormone secreted by pancreatic beta cells, regulating glucose uptake and storage.

• Glucagon: A hormone from alpha cells that raises blood glucose by stimulating glycogen breakdown.

• Gastrin: A hormone stimulating gastric acid secretion in the stomach.

• Secretin: A hormone stimulating bicarbonate secretion from the pancreas.

• Hepatocytes: Liver cells performing metabolism, detoxification, and protein synthesis.

• Peptide hormones: Protein-based hormones that act via receptors on target cells.

• Glycogenesis: Conversion of glucose into glycogen for storage.

• Glycogenolysis: Breakdown of glycogen to glucose.

• Hyperglycemia: Excess glucose levels in the blood.

• Hypoglycemia: Low glucose levels in the blood.

Lead Question - 2016 (Phase 2)

Name a peptide hormone which acts mainly on hepatocytes and enhances cellular glucose uptake and utilization :

(1) Gastrin
(2) Insulin
(3) Glucagon
(4) Secretin

Explanation: Insulin is a peptide hormone secreted by pancreatic beta cells. It promotes glucose uptake by cells, enhances glycogenesis, and reduces blood glucose levels. Other hormones regulate digestion or increase glucose but not cellular uptake. Hence, the correct answer is (2) Insulin.

1. In diabetes mellitus type I, the primary defect is:

(1) Insulin deficiency
(2) Insulin resistance
(3) Excess glucagon
(4) High gastrin levels

Explanation: Type I diabetes mellitus is caused by autoimmune destruction of pancreatic beta cells, resulting in insulin deficiency. Type II diabetes is due to insulin resistance. Excess glucagon and gastrin are unrelated. Correct answer is (1) Insulin deficiency.

2. A patient with hypoglycemia is likely to show which symptom?

(1) Frequent urination
(2) Sweating and tremors
(3) Excessive thirst
(4) Weight gain

Explanation: Hypoglycemia leads to activation of the sympathetic system, causing sweating, tremors, and palpitations. Frequent urination and excessive thirst are signs of hyperglycemia. Weight gain is unrelated. Correct answer is (2) Sweating and tremors.

3. Which hormone acts antagonistically to insulin?

(1) Secretin
(2) Gastrin
(3) Glucagon
(4) Prolactin

Explanation: Glucagon raises blood glucose levels by glycogenolysis and gluconeogenesis, opposing insulin’s action of lowering glucose. Secretin, gastrin, and prolactin do not regulate blood glucose. Correct answer is (3) Glucagon.

4. Which cells of the pancreas secrete insulin?

(1) Alpha cells
(2) Beta cells
(3) Delta cells
(4) Acinar cells

Explanation: Beta cells of the islets of Langerhans secrete insulin. Alpha cells secrete glucagon, delta cells secrete somatostatin, and acinar cells produce digestive enzymes. Correct answer is (2) Beta cells.

5. Clinical case: A diabetic patient is unconscious with low blood glucose. The emergency treatment is:

(1) IV insulin
(2) IV glucose
(3) Oral gastrin
(4) IV glucagon

Explanation: Hypoglycemic coma requires immediate correction of blood sugar. IV glucose is given to restore normal levels rapidly. Insulin would worsen the condition. Gastrin is unrelated. Glucagon can help, but IV glucose is preferred. Correct answer is (2) IV glucose.

6. Insulin facilitates glucose entry into cells by:

(1) Activating sodium channels
(2) Opening calcium channels
(3) Stimulating glucose transporters
(4) Increasing potassium influx

Explanation: Insulin promotes insertion of GLUT4 transporters into cell membranes of muscle and adipose tissues, enhancing glucose uptake. Sodium, calcium, and potassium channels are not directly responsible for glucose uptake. Correct answer is (3) Stimulating glucose transporters.

7. Assertion-Reason: Insulin lowers blood glucose. It increases glucose uptake by adipose and muscle cells.

(1) Both A and R true, R explains A
(2) Both A and R true, R does not explain A
(3) A true, R false
(4) A false, R true

Explanation: Insulin reduces blood glucose by promoting uptake into tissues such as muscle and fat. Both assertion and reason are true, and reason correctly explains assertion. Correct answer is (1).

8. Match the following:

A. Insulin
B. Glucagon
C. Gastrin
D. Secretin
(i) Increases blood glucose
(ii) Stimulates gastric acid
(iii) Enhances glucose uptake
(iv) Stimulates bicarbonate secretion

(1) A-iii, B-i, C-ii, D-iv
(2) A-i, B-iii, C-ii, D-iv
(3) A-iv, B-ii, C-i, D-iii
(4) A-ii, B-iv, C-iii, D-i

Explanation: Insulin enhances glucose uptake, glucagon increases blood glucose, gastrin stimulates gastric acid, and secretin stimulates bicarbonate secretion. Correct answer is (1) A-iii, B-i, C-ii, D-iv.

9. Fill in the blank: Insulin deficiency leads to ______ in blood glucose level.

(1) Decrease
(2) Increase
(3) No change
(4) Fluctuation only

Explanation: Lack of insulin causes hyperglycemia due to reduced glucose uptake and enhanced glycogenolysis. Blood glucose rises significantly, leading to diabetes mellitus. Correct answer is (2) Increase.

10. Choose the correct statements regarding insulin:

(1) It promotes glycogenesis
(2) It increases blood glucose
(3) It enhances lipogenesis
(4) It is secreted by beta cells

(1) 1,2 correct
(2) 2,3 correct
(3) 1,3,4 correct
(4) All correct

Explanation: Insulin promotes glycogenesis, enhances lipogenesis, and is secreted by beta cells of pancreas. It does not increase blood glucose; instead, it lowers it. Correct answer is (3) 1,3,4 correct.

Topic : Endocrine Disorders
Subtopic : Thyroid Disorders

Keyword Definitions :

• Graves’ Disease : An autoimmune disorder leading to hyperthyroidism due to excess thyroid hormone secretion.

• Hyperthyroidism : A condition caused by excessive thyroid hormone levels, leading to weight loss, heat intolerance, and anxiety.

• Thyroxine (T4) : The main hormone secreted by the thyroid gland regulating metabolism.

• Adrenal Gland : Endocrine gland producing cortisol, aldosterone, and adrenaline for stress response and metabolism.

• Hypothyroidism : A condition caused by underproduction of thyroid hormones, leading to fatigue and weight gain.

Lead Question - 2016 (Phase 2)
Graves’ disease is caused due to :
(1) hypersecretion of adrenal gland
(2) hyposecretion of thyroid gland
(3) hypersecretion of thyroid gland
(4) hyposecretion of adrenal gland

Explanation : Graves’ disease is an autoimmune disorder leading to hyperthyroidism. Antibodies stimulate thyroid hormone overproduction, causing symptoms like goiter, bulging eyes, heat intolerance, and weight loss. Thus, the correct answer is (3) hypersecretion of thyroid gland. It is a common endocrine disorder affecting metabolism and energy balance.

1. Which hormone increases basal metabolic rate in humans?
(1) Cortisol
(2) Thyroxine
(3) Insulin
(4) Glucagon

Explanation : Thyroxine, secreted by the thyroid gland, regulates basal metabolic rate and energy utilization. It stimulates protein synthesis, glucose metabolism, and heat production. Therefore, the correct answer is (2) Thyroxine, essential for growth, metabolism, and development, especially during childhood.

2. Clinical Case: A patient with bulging eyes, weight loss, and excessive sweating is most likely suffering from:
(1) Hypothyroidism
(2) Hyperthyroidism
(3) Addison’s disease
(4) Cushing’s syndrome

Explanation : The patient shows classic hyperthyroidism features, including exophthalmos, weight loss, and sweating. These are commonly associated with Graves’ disease, an autoimmune disorder. Thus, the correct answer is (2) Hyperthyroidism, which arises due to overproduction of thyroid hormones, increasing metabolic rate.

3. Which mineral is essential for thyroid hormone synthesis?
(1) Calcium
(2) Iodine
(3) Magnesium
(4) Iron

Explanation : Iodine is essential for thyroid hormone synthesis. Deficiency leads to goiter, hypothyroidism, and developmental delays. Thyroxine (T4) and triiodothyronine (T3) require iodine atoms in their structure. Hence, the correct answer is (2) Iodine, critical for thyroid gland function and normal metabolism.

4. Assertion (A): Hypothyroidism in adults may lead to myxedema.
Reason (R): Thyroxine deficiency causes decreased metabolic activity.
(1) Both A and R are true, R is correct explanation of A
(2) Both A and R are true, R is not correct explanation of A
(3) A is true, R is false
(4) A is false, R is true

Explanation : Hypothyroidism in adults results in myxedema with fatigue, puffiness, and low metabolism. Reduced thyroxine lowers basal metabolic activity. Hence, both A and R are true, and R correctly explains A. The correct answer is (1).

5. Match the endocrine disorder with its cause:
a. Addison’s disease - i. Hyposecretion of cortisol
b. Cushing’s syndrome - ii. Hypersecretion of cortisol
c. Diabetes mellitus - iii. Hyposecretion of insulin
d. Graves’ disease - iv. Hypersecretion of thyroid hormone
(1) a-i, b-ii, c-iii, d-iv
(2) a-ii, b-iii, c-iv, d-i
(3) a-iii, b-i, c-ii, d-iv
(4) a-iv, b-iii, c-i, d-ii

Explanation : Addison’s disease occurs due to hyposecretion of cortisol, Cushing’s syndrome due to excess cortisol, diabetes mellitus due to insulin deficiency, and Graves’ disease due to thyroid hypersecretion. Hence, the correct answer is (1) a-i, b-ii, c-iii, d-iv.

6. Which of the following is a symptom of hypothyroidism?
(1) Weight loss
(2) Increased heart rate
(3) Cold intolerance
(4) Bulging eyes

Explanation : Hypothyroidism leads to cold intolerance, fatigue, weight gain, and bradycardia due to reduced thyroid hormone levels. Bulging eyes and weight loss are signs of hyperthyroidism. Thus, the correct answer is (3) Cold intolerance, a classic symptom of underactive thyroid function.

7. Fill in the Blank: The autoimmune disorder that causes hyperthyroidism with exophthalmos is called ______.
(1) Addison’s disease
(2) Graves’ disease
(3) Myxedema
(4) Hashimoto’s thyroiditis

Explanation : The autoimmune disorder producing thyroid-stimulating antibodies that cause excessive thyroid hormone release and exophthalmos is Graves’ disease. Thus, the correct answer is (2) Graves’ disease, a major cause of hyperthyroidism globally.

8. Choose the correct statements:
A. Graves’ disease is an autoimmune disorder.
B. Hypothyroidism in children causes cretinism.
C. Iodine deficiency leads to goiter.
D. Cushing’s syndrome is due to hyposecretion of cortisol.
(1) A, B, and C
(2) A and D
(3) B and C only
(4) A, C, and D

Explanation : Statements A, B, and C are correct: Graves’ disease is autoimmune, hypothyroidism in children causes cretinism, and iodine deficiency leads to goiter. Cushing’s syndrome is due to hypersecretion, not hyposecretion, of cortisol. Hence, the correct answer is (1).

Chapter: Biochemistry