MICROANATOMY

Detailed explanation-1: -The menstrual cycle is regulated by hormones. Luteinizing hormone and follicle-stimulating hormone, which are produced by the pituitary gland, promote ovulation and stimulate the ovaries to produce estrogen and progesterone.

Detailed explanation-2: -The hormone responsible for these changes is progesterone, which is manufactured by the corpus luteum. Under the influence of progesterone, the uterus begins to create a highly vascularized bed for a fertilized egg.

Detailed explanation-3: -Estrogen levels rise and fall twice during the menstrual cycle. Estrogen levels rise during the mid-follicular phase and then drop precipitously after ovulation. This is followed by a secondary rise in estrogen levels during the mid-luteal phase with a decrease at the end of the menstrual cycle.

Detailed explanation-4: -In addition to regulating the menstrual cycle, estrogen affects the reproductive tract, the urinary tract, the heart and blood vessels, bones, breasts, skin, hair, mucous membranes, pelvic muscles, and the brain.