Question

Which hormones regulate menstrual cycle?

Answer 1

The menstrual cycle is regulated by a complex interplay of hormones such as follicle-stimulating hormone (FSH), luteinising hormone (LH), estrogen, and progesterone. During the follicular phase, levels of FSH and LH secreted from the anterior pituitary begin to rise. FSH, guided by gonadotropin-releasing hormone (GnRH) from the hypothalamus, helps primary follicles grow into Graafian follicles.

As the follicle matures, it begins to secrete estrogen, which leads to the proliferation of the endometrial lining of the uterus. Estrogen also provides positive feedback to stimulate the surge of LH this LH surge causes ovulation, i.e., the rupture of the Graafian follicle and release of the ovum.

The ruptured follicle transforms into the corpus luteum, which secretes progesterone during the luteal phase. Progesterone helps in maintaining the endometrium and preparing it for possible implantation of the embryo.

If fertilisation does not occur, progesterone levels drop, the corpus luteum degenerates, and the endometrium sheds, marking the onset of menstruation. High levels of progesterone also inhibit FSH and LH, thereby preventing further ovulation in that cycle.