Figure 42.13 The Ovarian and Uterine Cycles (A) The ovarian cycle progresses from the development of a follicle to ovulation and then to growth and finally to degeneration of the corpus luteum. (B) During a woman’s ovarian and uterine cycles, coordinated changes occur in the development of the ovarian follicle, the release of female sex steroids, and the endometrial lining of the uterus. The release of hypothalamic GnRH stimulates the release of pituitary LH and FSH which in turn control the development of the follicle and eventually ovulation. The cycles begin with the onset of menstruation; ovulation is at midcycle (yellow bar). (C) The ovarian and uterine cycles are under a complex series of positive and negative feedback controls involving several hormones.