Question

Menstruation is triggered by a drop in the levels of:

a. FSH.
b. LH
c. relaxin.
d. progesterone.
e. inhibin.

Answer 1

Menstruation is primarily triggered by a drop in the levels of progesterone, which leads to the breakdown of the endometrium and the start of the menstrual cycle.

Step-by-step explanation:

In the context of the menstrual cycle, menstruation is triggered by a drop in the levels of certain hormones. The correct answer to the question is d. progesterone. When no fertilized egg is implanted into the uterus, the corpus luteum, which forms after ovulation, begins to degenerate. This degeneration leads to a decrease in the levels of estrogen and progesterone. The reduction in progesterone levels causes the endometrium to break down, which initiates the next menstrual cycle. It is this decline in progesterone that is primarily responsible for the onset of menstruation. Additionally, the decrease in progesterone allows for the hypothalamus to send GnRH to the anterior pituitary, which in turn releases FSH and LH, starting the cycle over again.

Answer 2

The answer is: d. Progesterone.

Step-by-step explanation:

The menstrual cycle consists of a series of regular changes that naturally occur in the female reproductive system.

When the follicular phase begins, estrogen and progesterone levels are low. As a consequence, decomposition and shedding of the upper layers of the uterine lining, endometrium, and menstruation occurs.

The answer is: d. Progesterone.