Question

Explain the role of hormones during the menstrual cycle.

Answer 1

Role of hormones during the menstrual cycle are:

• The menstrual cycle is regulated by five main hormones: Gonadotropin-releasing hormone (GnRH), Follicle Stimulating Hormone (FSH), Luteinizing Hormone (LH), estrogens, and progesterone.
• GnRH is secreted by the hypothalamus and stimulates the anterior pituitary gland to release FSH and LH.
• FSH causes the development of ovarian follicles and stimulates them to produce estrogens.
• Estrogens repair and thicken the uterine lining (endometrium) after menstruation and stimulate the pituitary to release LH.
• A peak in estrogen levels causes an LH surge in the middle of the cycle (around day 14), triggering ovulation the release of the mature egg from the follicle.
• After ovulation, LH transforms the ruptured follicle into the corpus luteum, which secretes both progesterone and estrogens.
• Progesterone prepares the endometrium for implantation by making it thick, moist, and vascular; it also inhibits the release of GnRH, thus reducing FSH and LH secretion to prevent development of new follicles.
• If fertilization does not occur, the corpus luteum degenerates, leading to a drop in progesterone and estrogen levels.
• The decrease in hormones causes the endometrial lining to break down and menstruation to begin, marking the start of a new cycle.
• With progesterone level low, inhibition on FSH is removed, so FSH levels rise again to start follicle development for the next cycle.