Human Reproductive System pdf NCERT Related

Review Human Reproductive System pdf NCERT related questions and content

Seven days after ovulation, pituitary secretion of luteinizing hormone (LH) decreases rapidly. What is the cause of this decrease in secretion?

  • A. The anterior pituitary gland becomes unresponsive to the stimulatory effect of gonadotropin-releasing hormone (GnRH)
  • B. Estrogen from the developing follicles exerts a feedback inhibition on the hypothalamus
  • C. The rise in body temperature inhibits hypothalamic release of GnRH
  • D. Secretion of estrogen and progesterone by the corpus luteum suppresses hypothalamic secretion of GnRH and pituitary secretion of LH
Correct Answer: D

Rationale: Step 1: After ovulation, the follicle transforms into the corpus luteum.
Step 2: The corpus luteum secretes estrogen and progesterone.
Step 3: Estrogen and progesterone exert negative feedback on the hypothalamus.
Step 4: This inhibits the secretion of GnRH from the hypothalamus.
Step 5: Decreased GnRH leads to reduced LH secretion from the pituitary.
Therefore, the correct answer is D because the secretion of estrogen and progesterone by the corpus luteum suppresses the hypothalamic secretion of GnRH, resulting in decreased pituitary LH secretion.

Summary:
A: Incorrect. The anterior pituitary gland's responsiveness to GnRH is not the cause of the decrease in LH secretion.
B: Incorrect. Estrogen exerts negative feedback on the hypothalamus, not the pituitary.
C: Incorrect. Rise in body temperature does not directly inhibit GnRH secretion