Reproductive Physiology MCQs

Physiology · 40 free questions with answers & explanations.

1. LH surge triggers ovulation in females. The LH surge is triggered by high estrogen levels through which mechanism?
2. During the luteal phase of the menstrual cycle, which hormone is primarily responsible for maintaining the endometrium in the secretory phase?
3. On day 14 of a 28-day menstrual cycle, there is a sharp LH surge lasting 36–48 hours. Which cellular event in the dominant follicle does the LH surge directly trigger?
4. Human chorionic gonadotropin (hCG) is produced by the syncytiotrophoblast from the day of implantation. Its primary physiologic role in early pregnancy is:
5. The LH surge that triggers ovulation is caused by positive feedback of estradiol on the hypothalamic-pituitary axis. This positive feedback mechanism is unusual because it requires estradiol concentration to exceed a threshold for a sustained duration. Which cellular mechanism in pituitary gonadotrophs underlies the sensitisation required for the LH surge?
6. In spermatogenesis, Sertoli cells provide an essential support function including the blood-testis barrier. Which intercellular junction type forms the blood-testis barrier and what is its functional significance?
7. During the mid-cycle LH surge, the granulosa cell shifts from oestrogen production to progesterone production. What molecular mechanism underlies this 'luteinisation' process?
8. Inhibin B is predominantly secreted by which gonadal cell type, and what is its specific feedback role in the male reproductive axis?
9. The LH surge that triggers ovulation is paradoxically preceded by elevated estradiol acting on the hypothalamus/pituitary. What is this mechanism termed and at what estradiol level/duration is it triggered?
10. Sertoli cells produce androgen-binding protein (ABP) in response to FSH. ABP maintains high intratesticular testosterone. What other critical function do Sertoli cells perform that is directly regulated by testosterone?
11. During the luteal phase of the menstrual cycle, progesterone from the corpus luteum has multiple effects. Its thermogenic effect (raising basal body temperature by 0.3-0.5°C) is mediated by:
12. In males, the blood-testis barrier (BTB) is essential for immunological privilege of the testis. The BTB is formed by tight junctions between:
13. The LH surge in the midcycle is triggered by positive feedback of estradiol on the hypothalamic-pituitary axis. Estradiol above a threshold (~200 pg/mL for >36 hours) switches from negative to positive feedback at the pituitary level. The mechanism of this positive feedback involves upregulation of which pituitary component?
14. Human chorionic gonadotropin (hCG) is structurally identical to LH in its alpha subunit and shares the same receptor (LH/hCG receptor). The beta subunit of hCG has an additional C-terminal extension (carboxy-terminal peptide, CTP) with O-linked sialic acid residues. The functional consequence of this CTP with sialic acid is:
15. During parturition, Ferguson's reflex is a positive feedback mechanism: fetal head pressure on the cervix stimulates oxytocin release from the posterior pituitary, which increases uterine contractions, further pushing the head against the cervix. Why does uterine sensitivity to oxytocin increase dramatically at term compared to early pregnancy?
16. The LH surge triggering ovulation is preceded by a positive feedback effect of rising estradiol on the hypothalamic-pituitary axis. Which neuronal population in the hypothalamus expresses kisspeptin and mediates this estradiol-induced positive feedback, and where is it located?
17. During the secretory phase of the menstrual cycle, progesterone acts on endometrial glands via progesterone receptor (PR). Progesterone withdrawal at the end of the cycle triggers menstruation. The initial molecular event connecting progesterone withdrawal to prostaglandin-mediated menstruation is:
18. The preovulatory LH surge triggers ovulation through a cascade involving prostaglandin production in the follicle. Which specific event is immediately responsible for follicular rupture?
19. Human chorionic gonadotropin (hCG) maintains the corpus luteum in early pregnancy. The specific mechanism is:
20. The LH surge at midcycle triggers ovulation. The positive feedback loop of estradiol leading to the LH surge is mediated through which hypothalamic neuronal population?
21. A 24-year-old woman has a 28-day cycle. Progesterone levels are undetectable throughout the cycle. The most likely consequence and the mechanism of anovulation in this scenario are:
22. The acrosome reaction is essential for fertilisation. It is triggered by:
23. The LH surge that triggers ovulation occurs approximately 24-36 hours before follicular rupture. This midcycle LH surge is paradoxically triggered by estrogen through positive feedback, opposite to the usual negative feedback. This switch from negative to positive feedback requires:
24. In a male patient with Klinefelter syndrome (47,XXY), the characteristic hormonal profile is:
25. During the late follicular phase of the menstrual cycle, rising estrogen levels trigger the LH surge. Which receptor mechanism enables this positive feedback (pro-ovulatory) response of the pituitary to estrogen?
26. A male patient with bilateral cryptorchidism has normal testosterone but very elevated FSH with azoospermia. Inhibin B is undetectable. Which cell type and physiological concept explains the selective FSH elevation?
27. A 26-year-old woman is on combined oral contraceptives. Which of the following mechanisms MOST specifically suppresses ovulation?
28. In the LH surge that triggers ovulation, which POSITIVE feedback mechanism drives the preovulatory estrogen surge to stimulate gonadotroph LH release (instead of the usual negative feedback)?
29. A woman at 36 weeks gestation develops uterine contractions. Which of the following correctly describes the Ferguson reflex?
30. During the mid-cycle LH surge that triggers ovulation, a transient rise in progesterone secretion from granulosa cells precedes ovulation. What physiological role does this pre-ovulatory progesterone rise play in the positive feedback surge mechanism?
31. In the periovulatory phase, the LH surge triggers ovulation. Which of the following mediates the final rupture of the follicle wall?
32. Inhibin B is secreted by which cell type and has what primary endocrine effect?
33. The LH surge triggers ovulation approximately 36–44 hours later. Which cellular change within the dominant follicle causes the physical rupture of the follicle wall at ovulation?
34. A 16-year-old girl presents with primary amenorrhoea, normal breast development, absent pubic and axillary hair, and a 46,XY karyotype. Serum testosterone is in the high-normal male range. This presentation is consistent with:
35. A 25-year-old woman has a 28-day menstrual cycle. On which day does the LH surge occur, and what is the mechanism by which this LH surge triggers ovulation?
36. Testosterone is synthesized from cholesterol in Leydig cells via multiple enzymatic steps. Which enzyme deficiency would cause 46,XY individuals to be phenotypically female with absent Mullerian and Wolffian structures?
37. The LH surge triggers ovulation approximately 36 hours later. Which biochemical event in the dominant follicle is most directly responsible for the resumption of meiosis (completion of meiosis I) in the oocyte?
38. A 26-year-old female patient has FSH: 18 IU/L (elevated), LH: 22 IU/L (elevated), AMH: 0.1 ng/mL (very low), and antral follicle count of 2. These findings are consistent with premature ovarian insufficiency (POI). What is the primary pathophysiological mechanism of the elevated gonadotropins in this condition?
39. In the menstrual cycle, the LH surge that triggers ovulation typically occurs approximately 36 hours before follicular rupture. The primary trigger for the LH surge is:
40. Inhibin B is produced by ovarian granulosa cells and Sertoli cells. Its primary physiological role in the male is to: