The surge in luteinizing hormone (LH) that occurs during the middle of the ovarian cycle triggers which of the following events?

• A. The inhibition of follicle-stimulating hormone (FSH) secretion
• B. The onset of menstruation
• C. Ovulation, or the release of an egg from the ovary
• D. The thickening of the endometrial lining

Answer: (C)

Verified step by step guidance

1. Understand the role of luteinizing hormone (LH) in the ovarian cycle. LH is a hormone produced by the anterior pituitary gland and plays a critical role in regulating the female reproductive cycle.
2. Recall that the ovarian cycle consists of three phases: the follicular phase, ovulation, and the luteal phase. LH levels peak during the middle of the cycle, which is known as the LH surge.
3. Recognize that the LH surge is a key event that triggers ovulation. Ovulation is the process where a mature egg (oocyte) is released from the dominant follicle in the ovary.
4. Eliminate the incorrect options by understanding their timing in the cycle: (1) The inhibition of FSH secretion occurs later in the luteal phase due to high levels of progesterone. (2) The onset of menstruation happens at the end of the cycle if fertilization does not occur. (3) The thickening of the endometrial lining is primarily driven by estrogen during the follicular phase and progesterone during the luteal phase.
5. Conclude that the correct answer is ovulation, as the LH surge directly triggers the release of the egg from the ovary.