What is the source of the hormones that, when suddenly absent, are directly responsible for the onset of menstruation?

• A. Hypothalamus
• B. Pituitary
• C. Ovarian follicle
• D. Vestibular glands
• E. Corpus luteum

Answer: (E)

Verified step by step guidance

1. Understand the role of the corpus luteum in the menstrual cycle. The corpus luteum is formed from the remnants of the ovarian follicle after ovulation and is responsible for producing hormones, primarily progesterone, and some estrogen.
2. Recognize that progesterone and estrogen are crucial for maintaining the uterine lining, which is necessary for a potential pregnancy.
3. Identify that if pregnancy does not occur, the corpus luteum degenerates, leading to a significant drop in progesterone and estrogen levels.
4. Understand that the sudden decrease in these hormone levels causes the uterine lining to shed, resulting in menstruation.
5. Conclude that the corpus luteum is the source of the hormones whose absence directly triggers the onset of menstruation.