Biological Systems MCAT Practice Exam

What occurs during the luteal phase of the ovarian cycle?

1. The corpus luteum degenerates.

2. The endometrial lining sheds.

3. The corpus luteum secretes estrogen and progesterone.

4. The follicle matures.

The correct answer is: The corpus luteum secretes estrogen and progesterone.

During the luteal phase of the ovarian cycle, the corpus luteum, which forms from the remnants of the follicle after ovulation, plays a crucial role in preparing the endometrium for potential implantation of an embryo. The corpus luteum secretes both estrogen and progesterone. These hormones are vital for maintaining the thickened state of the endometrial lining, promoting further development and maturation in anticipation of a possible pregnancy. If fertilization does not occur, the corpus luteum eventually degenerates, leading to a drop in these hormone levels, and initiating the subsequent menstrual phase. Therefore, the secretion of estrogen and progesterone during the luteal phase directly supports the changes in the endometrial lining necessary for potential implantation.