Question

Given below are two statements:
Statement I: Ovulation is caused by LH surge leading to rupture of Graafian follicles.
Statement II: Graafian follicle remaining after ovulation transform into corpus luteum and secretes large amount of estrogen.
In the light of the above statements, choose the most appropriate answer from the options given below:

• A. Statement I is incorrect but Statement II is correct
• B. Both Statement I and Statement II are correct
• C. Both Statement I and Statement II are incorrect
• D. Statement I is correct but Statement II is incorrect

Hint:

Progesterone is known as the "pregnancy-maintaining hormone" because it is secreted in large amounts by the corpus luteum during the luteal phase. Estrogen levels peak twice: once before ovulation (follicular phase) and once moderately during the luteal phase.

Answer 1

The Correct Option is D

Concept:

• The menstrual cycle is regulated by pituitary hormones (LH, FSH) and ovarian hormones (estrogen, progesterone).

• In the middle of the cycle (around day 14), both LH and FSH attain a peak level.

• Rapid secretion of LH leading to its maximum level during the mid-cycle is called the

LH surge.

• The LH surge induces the rupture of the mature Graafian follicle, releasing the secondary oocyte (ovulation).

• Following ovulation, the ruptured Graafian follicle transforms under the influence of LH into the

corpus luteum.

• The corpus luteum secretes large amounts of

progesterone, which is essential for maintaining the endometrium of the uterus.

Step 1: Evaluate Statement I
Statement I is correct: The LH surge is the direct trigger that causes the Graafian follicle to rupture and release the ovum.

Step 2: Evaluate Statement II
Statement II is incorrect: The corpus luteum secretes large amounts of progesterone, not estrogen. (While it does secrete small amounts of estrogen, its primary and major secretion is progesterone).