Morphology and Physiology of the Ovary

A major aspect of reproductive capacity in women is its cyclical activity, a feature strikingly reflected in the growth and development of dominant follicles. Normally, the human ovaries produce a single dominant follicle that results in a single ovulation each menstrual cycle. The dominant follicle is responsible for the production of estradiol during the follicular phase of the cycle. After ovulation, the dominant follicle transforms into the corpus luteum, which secretes large amounts of progesterone during the luteal phase of the menstrual cycle. The estradiol and progesterone act on the uterus to prepare it for implantation of the human embryo. Therefore, to understand the menstrual cycle and female fertility, it is necessary to understand the life cycle of the dominant follicle and how it is controlled. Here, the structure/function relationships that underlie folliculogenesis, ovulation, and luteogenesis will be discussed. Attention will be focused on the human.