DESCRIBE THE ROLE OF HORMONES IN HUMAN MENSTRUATION CYCLE
The role of hormones in the human menstruation cycle is crucial in regulating and controlling the various phases and processes that occur during menstruation.
The menstrual cycle is primarily controlled by hormones released by the ovaries and the pituitary gland in the brain. There are four main hormones involved in this process: follicle-stimulating hormone (FSH), luteinizing hormone (LH), estrogen, and progesterone.
The cycle begins on the first day of menstruation and lasts for an average of 28 days, although it can vary in length from person to person.
During the first phase of the cycle, called the follicular phase, FSH is released by the pituitary gland. FSH stimulates the growth and maturation of the follicles in the ovaries, which contain the eggs. As the follicles develop, they produce estrogen, which in turn thickens the lining of the uterus, preparing it for potential implantation of a fertilized egg.
Around the middle of the cycle, LH is released by the pituitary gland, causing the dominant follicle to rupture and release the matured egg into the fallopian tubes. This event is known as ovulation and typically occurs around day 14 of the cycle.
After ovulation, the ruptured follicle in the ovary transforms into a structure called the corpus luteum, which secretes progesterone. Progesterone helps to further thicken the uterine lining and prepares it for potential implantation of a fertilized egg.
If fertilization does not occur, the corpus luteum starts to degenerate, leading to a decrease in progesterone levels. This drop in progesterone triggers the onset of menstruation, in which the thickened uterine lining is shed along with blood and tissue through the .
The decrease in hormone levels at the start of menstruation signals the pituitary gland to begin the next cycle by releasing FSH again. This initiates the development of a new set of follicles, restarting the menstrual cycle.
Overall, hormones play a crucial role in the human menstruation cycle by regulating the growth, release, and preparation of the egg, as well as the thickening and shedding of the uterine lining.