Topic: Gastrointestinal Physiology
Subtopic: Gastric Hormones
Keyword Definitions:
- Gastrin: Peptide hormone secreted by G cells of gastric antrum; stimulates gastric acid secretion and mucosal growth.
- G cells: Specialized endocrine cells in stomach antrum that secrete gastrin.
- Gastric acid: Hydrochloric acid secreted by parietal cells; essential for digestion.
- Enteroendocrine cells: Hormone-producing cells located in the gastrointestinal mucosa.
Lead Question - 2013
Gastrin is produced by :
a) Pancreas
b) Gastric antral cells
c) Pituitary
d) All
Answer and Explanation:
Correct answer is b) Gastric antral cells. Gastrin is secreted by G cells located in the gastric antrum and duodenum. It stimulates parietal cells to release hydrochloric acid, enhances gastric motility, and promotes mucosal growth. Neither pancreas nor pituitary secrete gastrin, making gastric antral cells the true source.
Guessed Questions for NEET PG:
1. Which cells secrete hydrochloric acid in the stomach?
a) G cells
b) Chief cells
c) Parietal cells
d) D cells
Explanation: Correct answer is c) Parietal cells. They secrete hydrochloric acid and intrinsic factor, crucial for vitamin B12 absorption and protein digestion.
2. Zollinger-Ellison syndrome is caused by:
a) Excess gastrin
b) Lack of pepsin
c) Low gastric acid
d) Low somatostatin
Explanation: Correct answer is a) Excess gastrin. Gastrinoma (gastrin-secreting tumor) causes gastric acid hypersecretion leading to peptic ulcers and diarrhea.
3. Which of the following inhibits gastrin release?
a) Somatostatin
b) Vagus nerve stimulation
c) Protein meal
d) Distension of stomach
Explanation: Correct answer is a) Somatostatin. Secreted by D cells, it inhibits gastrin release, reducing acid secretion and protecting gastric mucosa.
4. A patient with recurrent peptic ulcers shows high fasting gastrin levels. Most likely diagnosis is:
a) Pernicious anemia
b) Zollinger-Ellison syndrome
c) Achalasia
d) Crohn’s disease
Explanation: Correct answer is b) Zollinger-Ellison syndrome. Elevated gastrin due to gastrinoma causes uncontrolled gastric acid secretion and severe peptic ulcers.
5. Which hormone stimulates gallbladder contraction?
a) Gastrin
b) Secretin
c) Cholecystokinin
d) Motilin
Explanation: Correct answer is c) Cholecystokinin. CCK stimulates gallbladder contraction, pancreatic enzyme secretion, and slows gastric emptying, aiding fat digestion.
6. Gastrin primarily acts on which receptor?
a) CCK-B receptor
b) CCK-A receptor
c) Muscarinic M3 receptor
d) Histamine H1 receptor
Explanation: Correct answer is a) CCK-B receptor. Gastrin binds to CCK-B receptors on parietal cells and enterochromaffin-like cells to increase acid secretion via histamine release.
7. A patient with atrophic gastritis has decreased acid and gastrin secretion. Which cells are lost?
a) Parietal cells
b) Chief cells
c) G cells
d) Paneth cells
Explanation: Correct answer is a) Parietal cells. Their destruction reduces HCl secretion and intrinsic factor, leading to decreased gastrin feedback and pernicious anemia.
8. Gastrin secretion is increased by:
a) Protein meals
b) Hypocalcemia
c) Acidosis
d) Fasting
Explanation: Correct answer is a) Protein meals. Amino acids and peptides strongly stimulate G cells to secrete gastrin, enhancing acid secretion for protein digestion.
9. Which hormone is called the "nature’s antacid"?
a) Gastrin
b) Secretin
c) Somatostatin
d) Glucagon
Explanation: Correct answer is b) Secretin. Secretin stimulates bicarbonate secretion from pancreas, neutralizing gastric acid in duodenum, protecting mucosa from injury.
10. In vagotomy, gastrin release is reduced because:
a) Loss of acetylcholine stimulation
b) Loss of nitric oxide
c) Loss of dopamine
d) Loss of serotonin
Explanation: Correct answer is a) Loss of acetylcholine stimulation. Vagus nerve stimulates G cells via acetylcholine; vagotomy reduces this input, decreasing gastrin secretion.
Topic: Reproductive Physiology
Subtopic: Lactation Hormones
Keyword Definitions:
- Prolactin: Hormone from anterior pituitary stimulating milk production in mammary glands.
- Oxytocin: Posterior pituitary hormone causing milk ejection and uterine contraction.
- Galactopoiesis: Maintenance of milk production, mainly prolactin-mediated.
- Lactogenesis: Onset of milk secretion after childbirth.
- Relaxin: Hormone softening pelvic ligaments during pregnancy, not linked to lactation.
Lead Question - 2013
Primary hormone for secretion of milk ?
a) Oxytocin
b) Prolactin
c) Glucocorticoids
d) Relaxin
Answer and Explanation:
Correct answer is b) Prolactin. Prolactin from anterior pituitary is the primary hormone responsible for milk secretion and galactopoiesis. Oxytocin plays a role in milk ejection reflex but not production. Glucocorticoids support gland development, while relaxin affects pelvic ligaments but not lactation. Thus, prolactin is essential for milk secretion.
Guessed Questions for NEET PG:
1. Which hormone is essential for milk ejection reflex?
a) Prolactin
b) Oxytocin
c) Estrogen
d) Progesterone
Explanation: Correct answer is b) Oxytocin. Released from posterior pituitary, oxytocin stimulates contraction of myoepithelial cells around alveoli, pushing milk into ducts during suckling reflex.
2. Galactorrhea is caused by excess:
a) Estrogen
b) Progesterone
c) Prolactin
d) Oxytocin
Explanation: Correct answer is c) Prolactin. Hyperprolactinemia leads to galactorrhea, infertility, and menstrual disturbances. Commonly due to prolactinoma or dopamine antagonist drugs affecting prolactin regulation.
3. A lactating mother unable to eject milk despite normal production likely has deficiency of:
a) Prolactin
b) Oxytocin
c) Estrogen
d) Progesterone
Explanation: Correct answer is b) Oxytocin. Oxytocin deficiency or blocked reflex prevents milk ejection though prolactin maintains milk synthesis. Stress and anxiety also inhibit oxytocin release.
4. Which hormone inhibits milk secretion during pregnancy despite high prolactin levels?
a) Estrogen
b) Progesterone
c) Both estrogen and progesterone
d) Cortisol
Explanation: Correct answer is c) Both estrogen and progesterone. High levels block prolactin action on mammary alveoli. After delivery, their fall permits lactogenesis and milk secretion.
5. In Sheehan’s syndrome, failure of lactation occurs due to deficiency of:
a) Prolactin
b) Oxytocin
c) Growth hormone
d) ACTH
Explanation: Correct answer is a) Prolactin. Postpartum pituitary necrosis reduces anterior pituitary hormones, especially prolactin, leading to failure of lactation along with amenorrhea and hypothyroidism.
6. Which receptor mediates prolactin secretion regulation?
a) Dopamine D2 receptor
b) Serotonin 5-HT1 receptor
c) GABA receptor
d) Glucocorticoid receptor
Explanation: Correct answer is a) Dopamine D2 receptor. Dopamine inhibits prolactin secretion through D2 receptors. Dopamine antagonists increase prolactin causing galactorrhea and menstrual irregularities.
7. A mother with hypothyroidism presents with low milk secretion. Likely due to reduced:
a) Prolactin
b) TSH
c) TRH stimulation of prolactin
d) Oxytocin
Explanation: Correct answer is c) TRH stimulation of prolactin. Hypothyroidism causes reduced TRH, decreasing prolactin stimulation and impairing lactation. TRH normally enhances prolactin secretion in pituitary.
8. Which factor stimulates prolactin release during breastfeeding?
a) Stretch of cervix
b) Suckling reflex
c) Increased estrogen
d) Increased cortisol
Explanation: Correct answer is b) Suckling reflex. Nipple stimulation during suckling reduces hypothalamic dopamine inhibition, increasing prolactin and oxytocin release for milk production and ejection.
9. Which pituitary lobe secretes prolactin?
a) Posterior lobe
b) Intermediate lobe
c) Anterior lobe
d) All lobes
Explanation: Correct answer is c) Anterior lobe. Prolactin is secreted by lactotrophs of anterior pituitary. Posterior pituitary stores and releases oxytocin and vasopressin, not prolactin.
10. Bromocriptine suppresses lactation by:
a) Stimulating dopamine receptors
b) Blocking estrogen receptors
c) Inhibiting oxytocin receptors
d) Inhibiting progesterone receptors
Explanation: Correct answer is a) Stimulating dopamine receptors. Bromocriptine, a dopamine agonist, inhibits prolactin secretion via D2 receptors, suppressing milk production in hyperprolactinemia and unwanted lactation.
Topic: Endocrine Physiology
Subtopic: Glucagon Functions
Keyword Definitions:
• Glucagon: Hormone secreted by pancreatic alpha cells, raises blood glucose.
• Gluconeogenesis: Formation of glucose from non-carbohydrate sources.
• Glycogenesis: Formation of glycogen from glucose.
• Glycolysis: Breakdown of glucose to pyruvate for energy.
• Fatty acid synthesis: Conversion of acetyl-CoA into fatty acids.
• Insulin: Hormone that lowers blood glucose, opposite to glucagon.
• Ketogenesis: Formation of ketone bodies during fasting or diabetes.
• Liver: Primary organ for glucose metabolism and glucagon action.
• cAMP: Second messenger mediating glucagon effects.
• Glycogenolysis: Breakdown of glycogen to release glucose.
Lead Question - 2013
Glucagon stimulates
a) Gluconeogenesis
b) Glycogenesis
c) Fatty acid synthesis
d) Glycolysis
Explanation: Glucagon, secreted by pancreatic alpha cells, increases blood glucose by stimulating glycogenolysis and gluconeogenesis in the liver. It opposes insulin and promotes catabolic processes, especially during fasting or hypoglycemia. Therefore, the correct answer is a) Gluconeogenesis. It inhibits glycolysis and glycogenesis, and does not promote fatty acid synthesis.
1) Which cells secrete glucagon?
a) Beta cells
b) Alpha cells
c) Delta cells
d) G cells
Explanation: Glucagon is secreted by pancreatic alpha cells located in the islets of Langerhans. These cells release glucagon during hypoglycemia, stimulating glycogenolysis and gluconeogenesis in the liver to restore glucose levels. The correct answer is b) Alpha cells. Beta cells produce insulin, delta cells somatostatin, and G cells gastrin.
2) In fasting state, glucagon primarily acts on?
a) Liver
b) Skeletal muscle
c) Adipose tissue
d) Brain
Explanation: Glucagon primarily acts on the liver during fasting. It promotes glycogenolysis and gluconeogenesis, ensuring glucose availability for the brain and other vital organs. While it indirectly affects adipose tissue by stimulating lipolysis, the principal site of glucagon action is a) Liver, not muscle or brain.
3) Glucagon secretion is stimulated by?
a) Hypoglycemia
b) Hyperglycemia
c) High insulin
d) Low amino acids
Explanation: Hypoglycemia is the primary stimulus for glucagon release. Amino acids after a protein-rich meal also stimulate secretion. Glucagon prevents dangerously low blood glucose. Therefore, the correct answer is a) Hypoglycemia. High insulin and hyperglycemia inhibit glucagon secretion, while amino acids tend to stimulate it.
4) Which second messenger mediates glucagon action?
a) IP3
b) cAMP
c) DAG
d) Ca2+
Explanation: Glucagon acts via G-protein coupled receptors, activating adenylate cyclase to increase intracellular cAMP. This activates protein kinase A, which phosphorylates enzymes regulating glycogenolysis and gluconeogenesis. Thus, the correct answer is b) cAMP. IP3 and DAG are used by other hormones, not glucagon.
5) Clinical: A diabetic patient receives excessive insulin. Which hormone counters the hypoglycemia?
a) Cortisol
b) Glucagon
c) Aldosterone
d) Thyroxine
Explanation: In insulin-induced hypoglycemia, glucagon is the first-line defense. It rapidly raises blood glucose by stimulating hepatic glycogenolysis and gluconeogenesis. Cortisol and epinephrine act later. Thus, the correct answer is b) Glucagon. Aldosterone and thyroxine do not play roles in immediate glucose regulation.
6) Glucagon is inhibited by?
a) Hypoglycemia
b) Epinephrine
c) Insulin
d) Amino acids
Explanation: Insulin inhibits glucagon secretion by paracrine action within pancreatic islets. Hyperglycemia also suppresses glucagon release. Therefore, the correct answer is c) Insulin. Hypoglycemia and amino acids stimulate glucagon secretion, while epinephrine enhances glucagon release, not inhibition.
7) Clinical: In prolonged fasting, glucagon helps survival mainly by?
a) Stimulating glycolysis
b) Enhancing gluconeogenesis
c) Increasing glycogenesis
d) Promoting protein storage
Explanation: During prolonged fasting, glycogen stores deplete. Glucagon promotes gluconeogenesis from amino acids, glycerol, and lactate, maintaining blood glucose for the brain. Hence, the correct answer is b) Enhancing gluconeogenesis. It does not promote glycolysis or glycogenesis, and it mobilizes, not stores, proteins.
8) Glucagon mainly increases blood glucose by?
a) Glucose uptake
b) Glycogenolysis
c) Insulin secretion
d) Lipogenesis
Explanation: The immediate effect of glucagon is to increase blood glucose by glycogenolysis in the liver. This provides rapid glucose release during hypoglycemia. Therefore, the correct answer is b) Glycogenolysis. Glucose uptake and insulin secretion lower glucose, while lipogenesis stores energy, opposite of glucagon action.
9) Clinical: A patient with glucagonoma presents with?
a) Hypoglycemia
b) Necrolytic migratory erythema
c) Weight gain
d) Hypertension
Explanation: Glucagonoma, a rare pancreatic tumor, causes hyperglucagonemia. Classic presentation includes diabetes, anemia, and necrolytic migratory erythema (characteristic rash). Thus, the correct answer is b) Necrolytic migratory erythema. Patients usually have hyperglycemia, not hypoglycemia, and lose weight rather than gain it.
10) Glucagon increases ketone body formation by?
a) Stimulating lipogenesis
b) Enhancing ketogenesis
c) Activating glycolysis
d) Promoting glycogenesis
Explanation: In fasting and diabetes, glucagon stimulates ketogenesis in the liver by increasing fatty acid oxidation. This provides an alternative energy source for the brain and muscles. Hence, the correct answer is b) Enhancing ketogenesis. Lipogenesis and glycogenesis are inhibited, and glycolysis is suppressed under glucagon dominance.
Topic: Endocrine Physiology
Subtopic: Hormone Storage
Keyword Definitions:
• Insulin: Peptide hormone stored in secretory granules of beta cells.
• Cortisol: Steroid hormone synthesized on demand, not stored.
• Thyroxine: Iodine-containing thyroid hormone stored in colloid.
• Renin: Enzyme secreted by juxtaglomerular cells, stored in granules.
• Steroid hormones: Lipid-soluble, synthesized when needed, not stored.
• Peptide hormones: Stored in vesicles, released by exocytosis.
• Colloid: Protein-rich storage form for thyroid hormones.
• Exocytosis: Mechanism for peptide hormone secretion.
• Juxtaglomerular cells: Kidney cells producing and storing renin.
• Adrenal cortex: Site of cortisol production.
Lead Question - 2013
Which of the following is not stored in cell
a) Insulin
b) Cortisol
c) Thyroxin
d) Renin
Explanation: Peptide hormones like insulin and renin are stored in secretory granules. Thyroxine is stored in thyroid colloid. Cortisol, a steroid hormone, is synthesized on demand in the adrenal cortex and not stored within cells. Therefore, the correct answer is b) Cortisol. This property differentiates steroids from peptide and thyroid hormones.
1) Which hormone is secreted immediately without storage?
a) Cortisol
b) Insulin
c) Thyroxine
d) Renin
Explanation: Steroid hormones like cortisol are lipid-soluble and synthesized from cholesterol only when required. They cannot be stored in vesicles due to their solubility. Thus, the correct answer is a) Cortisol. Insulin and renin are stored in granules, while thyroxine is stored in thyroid colloid.
2) Clinical: A patient with Addison’s disease has low cortisol. Why is immediate secretion impaired?
a) Cortisol is stored
b) Cortisol requires synthesis
c) Cortisol binds vesicles
d) Cortisol is exocytosed
Explanation: Cortisol is not stored but synthesized from cholesterol when needed. In Addison’s disease, adrenal cortex fails to synthesize cortisol, leading to deficiency. Hence, secretion cannot be immediate. Correct answer is b) Cortisol requires synthesis. This contrasts peptide hormones that are stored and released rapidly.
3) Which hormone is stored in colloid form?
a) Cortisol
b) Thyroxine
c) Insulin
d) Renin
Explanation: Thyroxine (T4) and triiodothyronine (T3) are unique because they are stored extracellularly in the thyroid follicular colloid as thyroglobulin. Upon stimulation, they are cleaved and released. Hence, correct answer is b) Thyroxine. Cortisol is not stored, insulin and renin are stored in vesicles.
4) Clinical: Renin secretion increases in?
a) Hypertension
b) Hypotension
c) Hyperkalemia
d) Hypoglycemia
Explanation: Renin, stored in juxtaglomerular cells, is secreted in response to renal hypoperfusion, sympathetic activity, and low sodium. Thus, secretion increases during b) Hypotension. Hypertension suppresses renin, while hyperkalemia stimulates aldosterone, not renin. Hypoglycemia does not directly affect renin secretion.
5) Which hormone acts via intracellular receptors?
a) Cortisol
b) Insulin
c) Renin
d) ACTH
Explanation: Cortisol, being a steroid, is lipid-soluble and diffuses into cells to bind intracellular receptors. This alters gene transcription. Hence, correct answer is a) Cortisol. Insulin and ACTH act via membrane receptors, while renin is an enzyme, not a hormone-receptor ligand.
6) Clinical: A patient with hypothyroidism receives exogenous thyroxine. Where is natural thyroxine stored?
a) Adrenal cortex
b) Thyroid colloid
c) Pituitary gland
d) Pancreas
Explanation: Natural thyroxine is stored extracellularly in the thyroid gland’s colloid as part of thyroglobulin. It is later released into circulation when stimulated by TSH. Correct answer is b) Thyroid colloid. Adrenal cortex makes steroids, pituitary stores peptides, and pancreas stores insulin.
7) Which hormone is secreted by exocytosis?
a) Insulin
b) Cortisol
c) Thyroxine
d) Vitamin D
Explanation: Peptide hormones like insulin are stored in vesicles and secreted by exocytosis when triggered by glucose or other stimuli. Therefore, correct answer is a) Insulin. Steroids like cortisol diffuse across membranes, thyroxine is released by proteolysis, and vitamin D acts as a steroid hormone.
8) Clinical: In Cushing’s syndrome, why is cortisol secretion persistent?
a) Cortisol stored in cells
b) Cortisol synthesized continuously
c) Cortisol bound to vesicles
d) Cortisol released by exocytosis
Explanation: In Cushing’s syndrome, cortisol overproduction occurs due to continuous synthesis in adrenal cortex from cholesterol, not storage. Therefore, secretion persists. Correct answer is b) Cortisol synthesized continuously. Cortisol cannot be stored or released by vesicular exocytosis.
9) Renin is secreted by?
a) Macula densa
b) Juxtaglomerular cells
c) Podocytes
d) Collecting duct cells
Explanation: Renin is synthesized and stored in secretory granules of juxtaglomerular cells of kidney afferent arterioles. It regulates the renin-angiotensin-aldosterone system. Hence, correct answer is b) Juxtaglomerular cells. Macula densa senses sodium, podocytes form filtration barrier, collecting duct cells handle water reabsorption.
10) Clinical: Which hormone deficiency leads to hypoglycemia due to impaired gluconeogenesis?
a) Thyroxine
b) Insulin
c) Cortisol
d) Renin
Explanation: Cortisol stimulates gluconeogenesis during fasting. Its deficiency, as in Addison’s disease, impairs glucose production, leading to hypoglycemia. Correct answer is c) Cortisol. Insulin deficiency causes hyperglycemia, thyroxine regulates basal metabolism, and renin deficiency affects blood pressure, not glucose homeostasis.
Topic: Reproductive Physiology
Subtopic: Blood-Testis Barrier
Keyword Definitions:
• Blood-testis barrier: A physical barrier formed by tight junctions between Sertoli cells, preventing harmful substances from reaching developing sperm.
• Sertoli cells: Supporting cells of seminiferous tubules that provide structural and nutritional support to developing germ cells.
• Basal lamina: Thin extracellular layer forming the basement membrane of seminiferous tubules.
• Leydig cells: Interstitial cells of testis producing testosterone.
• Spermatogonia: Diploid germ cells located near basal lamina, precursors of spermatozoa.
• Tight junctions: Specialized intercellular connections that restrict paracellular movement of substances.
• Immunological privilege: Mechanism preventing immune attack on germ cells.
• Seminiferous tubules: Site of spermatogenesis within testes.
• Spermatogenesis: Process of sperm formation from spermatogonia.
• Androgen: Steroid hormones like testosterone produced by Leydig cells.
Lead Question - 2013
Blood tissue barrier in testis is formed by?
a) Basal lamina & interstitial cells
b) Adjacent sertoli cells with basal lamina
c) Basal lamina & spermatogonia
d) Basal lamina & leydig cells
Explanation: The blood-testis barrier is primarily formed by tight junctions between adjacent Sertoli cells, reinforced by the basal lamina. It separates basal and adluminal compartments, protecting developing germ cells from immune attack. Correct answer is b) Adjacent Sertoli cells with basal lamina. This barrier is vital for spermatogenesis.
1) Which cells secrete androgen-binding protein?
a) Leydig cells
b) Sertoli cells
c) Spermatogonia
d) Peritubular cells
Explanation: Sertoli cells produce androgen-binding protein under FSH influence. This protein maintains high testosterone concentration in seminiferous tubules, essential for spermatogenesis. Leydig cells produce testosterone, not ABP. Correct answer is b) Sertoli cells. Spermatogonia are germ cells, and peritubular cells provide contractile support.
2) Clinical: In mumps orchitis, which cells are primarily damaged?
a) Sertoli cells
b) Leydig cells
c) Spermatogonia
d) Basal lamina
Explanation: Mumps orchitis often damages Leydig cells, impairing testosterone production and leading to infertility. Sertoli cells may be affected secondarily, but primary pathology involves Leydig cells. Thus, correct answer is b) Leydig cells. Spermatogonia and basal lamina remain less affected initially.
3) Which hormone stimulates Leydig cells?
a) FSH
b) LH
c) Prolactin
d) Testosterone
Explanation: Luteinizing hormone (LH) stimulates Leydig cells to synthesize testosterone, essential for spermatogenesis and male secondary sexual characteristics. FSH acts on Sertoli cells, prolactin modulates LH effects, testosterone provides negative feedback. Correct answer is b) LH. This axis is key for reproductive physiology.
4) Clinical: A patient with low FSH has impaired spermatogenesis but normal testosterone. Which cells are affected?
a) Sertoli cells
b) Leydig cells
c) Spermatogonia
d) Peritubular cells
Explanation: FSH acts on Sertoli cells to support spermatogenesis, while LH regulates Leydig cells and testosterone. Low FSH impairs Sertoli function, disrupting germ cell maturation despite normal testosterone. Correct answer is a) Sertoli cells. This highlights the dual regulation of male fertility.
5) Which of the following forms the structural support in seminiferous tubules?
a) Spermatogonia
b) Sertoli cells
c) Leydig cells
d) Peritubular fibroblasts
Explanation: Sertoli cells act as “nurse cells” that provide structural support, nutrients, and paracrine signaling for germ cells in seminiferous tubules. Leydig cells lie outside tubules. Correct answer is b) Sertoli cells. Spermatogonia are developing germ cells, not supportive structures.
6) Clinical: A man has antibodies against his sperm. Which barrier failed?
a) Blood-testis barrier
b) Hemato-encephalic barrier
c) Placental barrier
d) Mucosal barrier
Explanation: The blood-testis barrier prevents sperm antigens from exposure to immune system. If it breaks, immune cells recognize sperm as foreign, causing infertility. Correct answer is a) Blood-testis barrier. Other barriers like placental or brain barriers are unrelated to spermatogenesis.
7) Which compartment houses spermatogonia?
a) Adluminal
b) Basal
c) Luminal
d) Interstitial
Explanation: Spermatogonia, the earliest germ cells, lie in the basal compartment of seminiferous tubules, near the basal lamina, outside the blood-testis barrier. As they mature, spermatocytes move into the adluminal compartment. Correct answer is b) Basal. This spatial separation is crucial for controlled germ cell development.
8) Clinical: A 25-year-old male presents with infertility and low inhibin levels. Which cells are defective?
a) Leydig cells
b) Sertoli cells
c) Spermatogonia
d) Basal lamina
Explanation: Sertoli cells secrete inhibin, which inhibits FSH. Low inhibin indicates Sertoli cell dysfunction, impairing spermatogenesis. Testosterone from Leydig cells may be normal. Correct answer is b) Sertoli cells. This emphasizes their dual role in germ cell support and hormonal regulation.
9) Testosterone diffuses into tubules through?
a) ABP binding
b) Exocytosis
c) Tight junctions
d) Osmosis
Explanation: Testosterone from Leydig cells enters seminiferous tubules bound to androgen-binding protein (ABP), maintaining high concentration for spermatogenesis. Thus, correct answer is a) ABP binding. It is not stored or secreted via exocytosis like peptides.
10) Clinical: Which condition disrupts spermatogenesis by breaking Sertoli cell junctions?
a) Chemotherapy
b) Diabetes
c) Hypertension
d) Hypothyroidism
Explanation: Chemotherapy drugs are toxic to rapidly dividing cells, including germ cells. They also disrupt Sertoli cell junctions forming the blood-testis barrier, causing infertility. Correct answer is a) Chemotherapy. Diabetes and hypertension affect vasculature, but do not directly disrupt Sertoli junctions.
Topic: Reproductive Physiology
Subtopic: Ovulation and Hormonal Regulation
Keyword Definitions:
• LH Surge: Rapid rise of luteinizing hormone before ovulation.
• Estrogen: Ovarian hormone responsible for endometrial proliferation.
• Progesterone: Hormone secreted mainly after ovulation by corpus luteum.
• Ovulation: Release of mature ovum triggered by LH surge.
• Follicle: Ovarian structure containing developing oocyte.
• Corpus Luteum: Post-ovulatory structure secreting progesterone.
• FSH: Follicle stimulating hormone aiding follicular maturation.
• Menstrual Cycle: Regular cyclic changes preparing for pregnancy.
• Hypothalamus: Releases GnRH to regulate LH and FSH.
• GnRH: Gonadotropin releasing hormone, triggers pituitary gonadotropins.
Lead Question - 2013
LH surge is associated with?
a) Increased estrogen & decreased progesterone
b) Increased estrogen & increased progesterone
c) Decreased estrogen & increased progesterone
d) Decreased estrogen & increased progesterone
Explanation: The LH surge occurs due to sustained high estrogen levels from the dominant follicle, which switches feedback from negative to positive on the hypothalamus and pituitary. Progesterone rises only after ovulation. Therefore, LH surge is associated with increased estrogen and decreased progesterone. The correct answer is a) Increased estrogen & decreased progesterone.
1) Which hormone is essential for maintaining luteal phase?
a) Estrogen
b) Progesterone
c) FSH
d) LH
Explanation: The luteal phase is maintained by progesterone, secreted by the corpus luteum under the influence of LH. Progesterone ensures endometrial receptivity and prepares for possible implantation. Without adequate progesterone, menstruation begins. Hence, the correct answer is b) Progesterone.
2) A woman presents with infertility. Her cycles are regular but without mid-cycle LH surge. What is most likely absent?
a) Follicular recruitment
b) Dominant follicle development
c) Corpus luteum formation
d) Estrogen production
Explanation: Absence of LH surge prevents ovulation, meaning no corpus luteum formation and no progesterone production. Estrogen may still be present from follicular phase. Thus, the most likely absent feature is c) Corpus luteum formation.
3) Which ovarian hormone has positive feedback on LH surge?
a) Estrogen
b) Progesterone
c) Inhibin
d) Activin
Explanation: Estrogen, when sustained at high levels, exerts a positive feedback effect on the hypothalamus and pituitary, resulting in the LH surge that triggers ovulation. Progesterone and inhibin act mainly with negative feedback. Hence, the correct answer is a) Estrogen.
4) A patient has mid-cycle pelvic pain (Mittelschmerz). Which hormonal event is most closely related?
a) LH surge
b) Decline in FSH
c) Rise in progesterone
d) Fall in estrogen
Explanation: Mittelschmerz, or mid-cycle pain, coincides with follicular rupture during ovulation. This event is triggered by the LH surge. Thus, the hormonal event most closely related is a) LH surge.
5) Which hormone prevents multiple ovulations during one cycle?
a) Estrogen
b) Progesterone
c) Inhibin
d) LH
Explanation: Progesterone from corpus luteum provides negative feedback on GnRH, LH, and FSH secretion, preventing additional ovulations within the same cycle. Thus, the correct answer is b) Progesterone.
6) A 28-year-old woman has irregular cycles. Serum shows no mid-cycle LH surge. What phase defect is present?
a) Luteal phase defect
b) Anovulatory cycle
c) Short follicular phase
d) Hyperprolactinemia
Explanation: Lack of mid-cycle LH surge indicates failure of ovulation, making the cycle anovulatory. Luteal phase cannot occur without ovulation. Thus, the correct answer is b) Anovulatory cycle.
7) Which structure produces progesterone after ovulation?
a) Theca interna
b) Granulosa lutein cells
c) Oocyte
d) Hypothalamus
Explanation: After ovulation, granulosa cells become granulosa lutein cells in the corpus luteum, which secrete progesterone. Theca interna produces androgens before ovulation. Thus, the correct answer is b) Granulosa lutein cells.
8) A woman on clomiphene therapy develops multiple follicles. What does clomiphene inhibit?
a) Estrogen receptors in hypothalamus
b) Progesterone receptors in uterus
c) LH receptors in ovary
d) FSH receptors in ovary
Explanation: Clomiphene is an anti-estrogen that blocks hypothalamic estrogen receptors, preventing negative feedback, increasing GnRH and stimulating FSH/LH release, leading to follicle growth. Hence, the correct answer is a) Estrogen receptors in hypothalamus.
9) Which event follows LH surge most directly?
a) Follicle rupture
b) Endometrial shedding
c) Decline in estrogen
d) Inhibin secretion
Explanation: The LH surge directly causes follicle rupture, leading to ovulation. Other events like endometrial shedding occur later if implantation does not happen. Thus, the correct answer is a) Follicle rupture.
10) A 30-year-old woman with PCOS has persistently high estrogen but no LH surge. What is the likely cause?
a) Absent GnRH pulses
b) Progesterone deficiency
c) Loss of estrogen positive feedback
d) Excess androgen production
Explanation: In PCOS, estrogen is present but fails to induce an LH surge due to altered GnRH pulsatility and high androgens. The key mechanism is loss of estrogen’s positive feedback effect. The correct answer is c) Loss of estrogen positive feedback.
Topic: Reproductive Physiology
Subtopic: Ovulation and Hormonal Regulation
Keyword Definitions:
• LH Surge: A sudden rise in luteinizing hormone triggering ovulation.
• Ovulation: Release of a mature ovum from the dominant follicle.
• Estrogen: Hormone secreted by granulosa cells, stimulates LH surge.
• Progesterone: Secreted post-ovulation, prepares endometrium for implantation.
• Corpus Luteum: Structure formed after ovulation producing progesterone.
• GnRH: Hypothalamic hormone stimulating LH and FSH secretion.
• Follicle: Ovarian structure enclosing the developing oocyte.
• Inhibin: Hormone reducing FSH secretion, secreted by granulosa cells.
• Mittelschmerz: Mid-cycle ovulatory pain due to follicular rupture.
• Anovulation: Absence of ovulation often leading to infertility.
Lead Question - 2013
The interval between ovulation and LH surge is ?
a) 12-24 hours
b) 24-48 hours
c) 48-72 hours
d) 72-96 hours
Explanation: The LH surge occurs approximately 24 to 36 hours before ovulation, triggering enzymatic and structural changes leading to follicle rupture. This interval is clinically significant for fertility prediction and assisted reproduction. Therefore, the correct answer is a) 12-24 hours, as ovulation follows closely after LH surge.
1) Which hormone directly causes follicle rupture?
a) Estrogen
b) Progesterone
c) LH
d) FSH
Explanation: Follicle rupture during ovulation is directly caused by the LH surge, which stimulates enzymatic activity and follicular wall breakdown. Estrogen primes the follicle, while progesterone dominates later. Thus, the correct answer is c) LH.
2) A woman undergoing infertility evaluation has LH surge but no ovulation. Which defect is most likely?
a) Follicular rupture defect
b) Luteal insufficiency
c) Estrogen deficiency
d) GnRH deficiency
Explanation: Presence of LH surge but absence of ovulation suggests a follicular rupture defect. Despite adequate hormonal signaling, the follicle fails to release the oocyte. This is uncommon but clinically significant in infertility. The correct answer is a) Follicular rupture defect.
3) Which hormone level is highest immediately after ovulation?
a) Estrogen
b) Progesterone
c) LH
d) FSH
Explanation: After ovulation, progesterone levels rise significantly due to corpus luteum formation. Estrogen also remains but is not dominant. LH levels decline rapidly after the surge. Therefore, the correct answer is b) Progesterone.
4) A 26-year-old woman experiences cyclic mid-cycle pain. What best explains this event?
a) LH surge
b) Estrogen withdrawal
c) Follicle rupture
d) Progesterone secretion
Explanation: Mid-cycle pain, or Mittelschmerz, occurs due to follicular rupture releasing the ovum and peritoneal irritation from follicular fluid. This is linked to the LH surge event. Thus, the correct answer is c) Follicle rupture.
5) Which of the following prevents premature LH surge?
a) Progesterone
b) Inhibin
c) Estradiol
d) Activin
Explanation: Progesterone provides negative feedback on GnRH and gonadotropins, preventing premature LH surge before follicular maturation is complete. This regulation ensures ovulation occurs at the right phase. Thus, the correct answer is a) Progesterone.
6) A woman has irregular cycles and ultrasound shows no dominant follicle despite rising estrogen. What is absent?
a) LH surge
b) FSH secretion
c) Corpus luteum
d) Follicular recruitment
Explanation: Without a dominant follicle, the estrogen rise is insufficient for positive feedback. This leads to absent LH surge and no ovulation. Corpus luteum cannot form without ovulation. Hence, the correct answer is a) LH surge.
7) Which ovarian structure produces inhibin?
a) Theca interna
b) Granulosa cells
c) Oocyte
d) Corpus luteum
Explanation: Inhibin is secreted by granulosa cells of the ovary. It provides negative feedback on the pituitary to suppress FSH secretion, ensuring only one dominant follicle matures. Thus, the correct answer is b) Granulosa cells.
8) A 30-year-old woman has PCOS. Which hormonal abnormality best explains absent LH surge?
a) Low estrogen
b) High progesterone
c) Abnormal GnRH pulses
d) Low FSH
Explanation: In PCOS, altered GnRH pulsatility leads to excessive LH and impaired FSH response, preventing normal estrogen feedback and LH surge. Hence, the correct answer is c) Abnormal GnRH pulses.
9) During the menstrual cycle, when is estrogen’s positive feedback most significant?
a) Early follicular phase
b) Mid follicular phase
c) Late follicular phase
d) Luteal phase
Explanation: Estrogen exerts positive feedback only in the late follicular phase, leading to the LH surge. In all other phases, estrogen predominantly has negative feedback. Therefore, the correct answer is c) Late follicular phase.
10) A woman undergoing assisted reproduction is monitored for LH surge. Ovulation is expected how many hours later?
a) 12-24 hours
b) 24-48 hours
c) 48-72 hours
d) >72 hours
Explanation: In clinical practice, ovulation occurs 24 to 36 hours after the LH surge. This timing is critical for ovum retrieval in assisted reproduction. The correct answer is b) 24-48 hours.
Topic: Endocrinology
Subtopic: Hormonal Changes with Aging
Keyword Definitions:
• Growth Hormone (GH): Hormone secreted by anterior pituitary, declines with age.
• Prolactin: Pituitary hormone for lactation, generally stable with age.
• Parathormone (PTH): Hormone regulating calcium and phosphate metabolism, increases with aging.
• Insulin: Pancreatic hormone regulating blood glucose, may show resistance with age but secretion doesn’t consistently increase.
• Aging: Biological process associated with hormonal alterations.
• Osteoporosis: Bone condition worsened by altered calcium-phosphate balance.
• Calcium Homeostasis: Balance maintained by PTH, vitamin D, and calcitonin.
• Vitamin D: Steroid hormone aiding calcium absorption, often deficient with age.
• Hyperparathyroidism: Excess PTH activity, more common in elderly.
• Endocrine Aging: Progressive hormonal changes impacting multiple organs.
Lead Question - 2013
Which hormone increases with age ?
a) GH
b) Prolactin
c) Parathormone
d) Insulin
Explanation: With advancing age, parathormone (PTH) secretion gradually increases to counteract reduced calcium absorption and vitamin D deficiency. This rise contributes to age-related osteoporosis. Other hormones like GH decline, prolactin remains stable, and insulin resistance may rise but not its secretion. The correct answer is c) Parathormone.
1) Which hormone declines progressively after puberty?
a) GH
b) PTH
c) Prolactin
d) Insulin
Explanation: Growth hormone secretion peaks during adolescence and declines with aging, contributing to reduced muscle mass and increased fat deposition. PTH increases, prolactin is stable, and insulin secretion is variable. Correct answer is a) GH.
2) A 70-year-old woman with osteoporosis is found to have high PTH. Which mechanism best explains this?
a) Increased bone formation
b) Reduced calcium absorption
c) Elevated calcitonin
d) Excess insulin
Explanation: Age-related decline in vitamin D reduces intestinal calcium absorption. To compensate, PTH increases, mobilizing calcium from bone, leading to osteoporosis. Hence, the correct answer is b) Reduced calcium absorption.
3) Which hormone secretion is relatively unchanged with aging?
a) GH
b) Prolactin
c) PTH
d) Cortisol
Explanation: Prolactin levels remain relatively stable throughout life except in pregnancy and lactation. GH declines, PTH rises, and cortisol secretion rhythm may alter slightly with age. Correct answer is b) Prolactin.
4) A 65-year-old man with recurrent fractures has normal vitamin D but raised PTH. What is the likely diagnosis?
a) Primary hyperparathyroidism
b) Secondary hyperparathyroidism
c) GH deficiency
d) Osteomalacia
Explanation: Elevated PTH in the elderly with normal vitamin D suggests primary hyperparathyroidism. Secondary hyperparathyroidism usually shows vitamin D deficiency. GH deficiency does not cause high PTH. Correct answer is a) Primary hyperparathyroidism.
5) Which hormone regulates calcium by decreasing serum calcium?
a) Calcitonin
b) PTH
c) Vitamin D
d) Aldosterone
Explanation: Calcitonin secreted by thyroid parafollicular cells lowers serum calcium by inhibiting bone resorption. PTH increases calcium, Vitamin D enhances absorption, and aldosterone regulates sodium not calcium. Correct answer is a) Calcitonin.
6) An elderly patient with kyphosis and bone pain has high alkaline phosphatase and high PTH. Which condition is most likely?
a) Osteoporosis
b) Paget’s disease
c) Osteitis fibrosa cystica
d) Osteoarthritis
Explanation: Osteitis fibrosa cystica is caused by prolonged high PTH, leading to bone resorption, cystic lesions, and deformities. Osteoporosis does not typically elevate alkaline phosphatase. Correct answer is c) Osteitis fibrosa cystica.
7) Which hormone decreases insulin sensitivity with age?
a) Cortisol
b) GH
c) PTH
d) Calcitonin
Explanation: Cortisol contributes to age-related insulin resistance by promoting gluconeogenesis and impairing glucose uptake. GH declines with age, PTH regulates calcium, and calcitonin does not affect insulin. Correct answer is a) Cortisol.
8) A 60-year-old woman presents with fatigue, bone pain, and hypercalcemia. Labs show elevated PTH. Which is the best next step?
a) Vitamin D supplementation
b) Parathyroid imaging
c) Insulin therapy
d) GH replacement
Explanation: Hypercalcemia with elevated PTH strongly suggests hyperparathyroidism. Parathyroid imaging (ultrasound, sestamibi scan) is done to localize adenoma for surgery. Vitamin D deficiency shows low calcium with high PTH. Correct answer is b) Parathyroid imaging.
9) Which of the following is not a function of PTH?
a) Increases calcium reabsorption in kidney
b) Increases phosphate reabsorption in kidney
c) Stimulates bone resorption
d) Stimulates vitamin D activation
Explanation: PTH increases calcium reabsorption but decreases phosphate reabsorption in the kidney to prevent calcium-phosphate precipitation. It also stimulates vitamin D activation and bone resorption. Therefore, the incorrect function is b) Increases phosphate reabsorption.
10) In elderly patients, PTH rise is most associated with which clinical consequence?
a) Improved bone density
b) Increased fracture risk
c) Reduced urinary calcium
d) Enhanced muscle strength
Explanation: Elevated PTH in elderly increases bone resorption, weakening bone and leading to osteoporosis and fractures. It does not improve bone density or muscle strength. Correct answer is b) Increased fracture risk.
Topic: Pituitary Hormones
Subtopic: Prolactin
Keyword Definitions:
• Prolactin: Hormone secreted by anterior pituitary, regulates milk production.
• Unit of Measurement: Standard way to express hormone concentration in blood.
• Reference Range: Normal prolactin is 5–25 ng/ml in females, slightly lower in males.
• Hyperprolactinemia: Condition of elevated prolactin levels, causes infertility and galactorrhea.
• Hypopituitarism: Decreased secretion of pituitary hormones including prolactin.
Lead Question - 2013
The following is the unit for prolactin level of 20 in blood?
a) mg/ml
b) ng/ml
c) mg/L
d) ng/L
Explanation: Prolactin is measured in nanograms per milliliter (ng/ml). A value of 20 indicates normal upper range for women, while men typically have lower levels. Measurement is essential for diagnosing hyperprolactinemia. Therefore, the correct answer is ng/ml, as standard hormone assays report prolactin in these units.
1) Which anterior pituitary hormone controls prolactin secretion?
a) Dopamine
b) GH
c) TSH
d) FSH
Explanation: Prolactin is primarily inhibited by hypothalamic dopamine, not controlled by stimulatory hormones like GH or TSH. This negative control is unique. If dopamine is reduced, prolactin rises. Therefore, the correct answer is Dopamine, acting as a prolactin-inhibiting factor through the tuberoinfundibular pathway.
2) A 30-year-old woman presents with galactorrhea and amenorrhea. Most likely cause?
a) Low prolactin
b) High prolactin
c) Low cortisol
d) High GH
Explanation: Galactorrhea with amenorrhea strongly suggests hyperprolactinemia. Elevated prolactin inhibits GnRH secretion, leading to menstrual irregularities. Cortisol or GH abnormalities do not cause this triad. Therefore, the correct answer is High prolactin, most often from prolactinoma or dopamine antagonist drug use.
3) Prolactin levels are usually measured by?
a) ELISA
b) RIA
c) Western blot
d) PCR
Explanation: Prolactin is measured using immunoassays, commonly ELISA or RIA. These techniques use antibodies specific for prolactin to quantify levels in serum. Molecular biology techniques like PCR are not used for hormones. Therefore, the correct answer is ELISA, which is widely available in diagnostic labs.
4) Which drug causes increased prolactin levels?
a) Bromocriptine
b) Risperidone
c) Cabergoline
d) Dopamine
Explanation: Risperidone is an antipsychotic that blocks dopamine receptors, removing inhibitory control on prolactin secretion. This often causes drug-induced hyperprolactinemia. In contrast, bromocriptine and cabergoline are dopamine agonists used to lower prolactin. Therefore, the correct answer is Risperidone, a common iatrogenic cause.
5) A patient on antipsychotics develops infertility. Which hormone is implicated?
a) Prolactin
b) GH
c) ACTH
d) Cortisol
Explanation: Antipsychotics elevate prolactin due to dopamine blockade, leading to hypogonadism, infertility, and galactorrhea. GH, ACTH, and cortisol are unrelated to this mechanism. Therefore, the hormone implicated is Prolactin, explaining infertility in patients treated with such medications.
6) Prolactinomas are best treated by?
a) Surgery
b) Radiotherapy
c) Dopamine agonists
d) Chemotherapy
Explanation: First-line treatment for prolactinomas is medical, not surgical. Dopamine agonists like bromocriptine or cabergoline suppress prolactin secretion and shrink tumor size effectively. Surgery is reserved for resistant cases. Therefore, the correct answer is Dopamine agonists, which are highly effective and safe.
7) A woman presents with headache, bitemporal hemianopia, and galactorrhea. Cause?
a) Prolactinoma
b) Cushing disease
c) Acromegaly
d) Hypothyroidism
Explanation: Headache, visual field defects, and galactorrhea indicate a pituitary macroadenoma compressing the optic chiasm. Most common functional pituitary tumor is prolactinoma, which also raises prolactin. Cushing’s or acromegaly cause other features. Therefore, the correct answer is Prolactinoma causing mass effect and hypersecretion.
8) Which hormone is structurally similar to prolactin?
a) GH
b) ACTH
c) Insulin
d) Cortisol
Explanation: Prolactin and growth hormone belong to the same protein family, showing structural and evolutionary similarity. They both act via JAK-STAT pathways. ACTH, insulin, and cortisol differ in structure and function. Therefore, the correct answer is GH, with close resemblance to prolactin.
9) A patient with primary hypothyroidism has raised prolactin because?
a) High TSH stimulates lactotrophs
b) High TRH stimulates prolactin
c) Low T4 directly stimulates prolactin
d) Cortisol deficiency
Explanation: TRH stimulates both TSH and prolactin secretion. In hypothyroidism, TRH rises, causing hyperprolactinemia. TSH does not directly stimulate lactotrophs. Cortisol deficiency is unrelated. Therefore, the correct answer is High TRH stimulates prolactin, explaining galactorrhea in hypothyroid patients.
10) Prolactin primarily acts on which receptor type?
a) G-protein coupled
b) Tyrosine kinase
c) JAK-STAT
d) Steroid receptor
Explanation: Prolactin binds to cytokine family receptors and activates JAK-STAT signaling pathways to mediate gene transcription. It does not use GPCRs, tyrosine kinases, or intracellular steroid receptors. Therefore, the correct answer is JAK-STAT, responsible for prolactin’s cellular effects.
Topic: Fertilization
Subtopic: Sperm Viability
Keyword Definitions:
• Sperm viability: Duration sperm remain alive and functional in female tract.
• Capacitation: Biochemical changes in sperm enabling fertilization.
• Acrosome reaction: Release of enzymes to penetrate ovum.
• Cervical mucus: Secretion that supports or hinders sperm survival.
• Fertilization window: Time during which conception is possible.
Lead Question - 2013
Human sperm remains fertile for how many hours in a female genital tract?
a) 6-8 hrs
b) 12-24 hrs
c) 24-48 hrs
d) 72-96 hrs
Explanation: After ejaculation, human sperm can survive for 48 to 72 hours, but optimal fertilizing capacity is usually within 24 to 48 hours. This viability depends on cervical mucus and female tract conditions. Thus, the correct answer is 24-48 hrs, representing peak fertilizing potential.
1) What is the minimum time required for sperm capacitation?
a) 1 hour
b) 4-6 hours
c) 12 hours
d) 24 hours
Explanation: Capacitation occurs in the female genital tract, taking about 4 to 6 hours. This process prepares sperm for acrosome reaction and fertilization. It does not occur immediately after ejaculation. Therefore, the correct answer is 4-6 hours, critical for fertilization.
2) A 28-year-old woman with regular cycles wants to conceive. Best time for intercourse?
a) Day 1-3
b) Day 5-9
c) Day 12-16
d) Day 20-25
Explanation: Fertile period is around ovulation, typically between day 12-16 in a 28-day cycle. Intercourse during this period provides maximum chance of conception, as sperm remain viable and ovum survives 12-24 hours. Hence, the correct answer is Day 12-16.
3) Which female structure stores sperm temporarily?
a) Fallopian tube
b) Cervix
c) Ovary
d) Uterus
Explanation: Cervical mucus and cervical crypts serve as reservoirs for sperm, allowing gradual release into the uterus and tubes. This mechanism prolongs fertility and enhances conception chances. Thus, the correct answer is Cervix, which helps sperm survival.
4) A 32-year-old woman with infertility is found to have thick cervical mucus. Likely effect?
a) Increased sperm motility
b) Reduced sperm survival
c) Early ovulation
d) Increased implantation
Explanation: Thick, hostile cervical mucus impedes sperm entry and reduces their survival, often causing infertility. Normally, estrogen makes mucus watery to support sperm passage. Hence, the correct answer is Reduced sperm survival.
5) How long does the ovum remain viable for fertilization?
a) 6-8 hours
b) 12-24 hours
c) 48-72 hours
d) 96 hours
Explanation: The ovum remains viable for only 12 to 24 hours after ovulation. Unlike sperm, eggs have a shorter fertile lifespan. Fertilization must occur within this window for successful conception. Therefore, the correct answer is 12-24 hours.
6) A couple presents with infertility. Semen analysis shows normal sperm count but no pregnancy after 1 year. Possible reason?
a) Short sperm viability
b) Anovulation
c) High testosterone
d) Low LH
Explanation: If sperm parameters are normal, female factors like anovulation are common causes of infertility. Without ovulation, fertilization cannot occur despite viable sperm. Hence, the correct answer is Anovulation.
7) Sperm undergo acrosome reaction in which part of female tract?
a) Cervix
b) Vagina
c) Ampulla of fallopian tube
d) Uterus
Explanation: Acrosome reaction occurs in the ampullary region of the fallopian tube, where fertilization normally takes place. This ensures penetration of the zona pellucida. Therefore, the correct answer is Ampulla of fallopian tube.
8) A 26-year-old woman uses barrier contraception. How does it prevent fertilization?
a) Prevents ovulation
b) Blocks sperm entry
c) Alters endometrium
d) Suppresses LH surge
Explanation: Barrier methods like condoms prevent fertilization by blocking sperm from entering the female genital tract. They do not affect ovulation or endometrium. Thus, the correct answer is Blocks sperm entry.
9) Sperm motility depends primarily on?
a) Flagellar activity
b) Mitochondrial ATP
c) Calcium influx
d) All of the above
Explanation: Sperm motility is maintained by ATP from mitochondria, flagellar action, and calcium influx regulating motility. All mechanisms contribute synergistically. Thus, the correct answer is All of the above.
10) A patient with hyperprolactinemia presents with infertility. Cause?
a) Reduced sperm viability
b) Failure of ovulation
c) Uterine abnormalities
d) Tubal block
Explanation: Hyperprolactinemia suppresses GnRH, reducing LH and FSH, leading to anovulation. This prevents conception despite normal sperm viability. Hence, the correct answer is Failure of ovulation, commonly caused by prolactinomas or antipsychotic drugs.