The female reproductive system consists of a series of organs that function together to produce and nourish viable offspring. The organs that comprise the female reproductive system include the ovaries, the uterine tubes, the uterus, and the vagina. Mammary glands are also important for the nourishment of offspring, but are not part of the female reproductive system as such.
The follicle is the structural and functional unit of the ovary, and consists of a female gamete (an oocyte) surrounded by follicular (granulosa) cells. All oocytes and follicles originate prenatally and continue to develop and mature throughout a woman's reproductive life.
Female reproductive organs undergo monthly cyclic changes in their histologic organization and functional activity, known as the ovarian or menstrual cycle, which is regulated by the complex interplay of hypothalamic, pituitary, and ovarian hormones. As a result, usually a single oocyte is released each month, and the uterus is prepared to receive an embryo.
The ovary produces the female sex hormones estrogen and progesterone.
Estrogen promotes the development of female secondary sex characteristics, the maturation of ovarian follicles, and the restoration of the endometrium after menstruation.
Progesterone stimulates secretion by the endometrial glands to prepare the uterus for pregnancy.
The primary female reproductive organ is the ovary, which functions to produce female gametes (oocytes, ova) and the female sex hormones estrogen and progesterone. The paired ovaries are located in the pelvic cavity, one on each side of the uterus, and are held in place by the broad ligament (Figure 15-1A). The overall organization of the ovary is as follows (Figure 15-1B):
Arrangement of female reproductive organs, structure of the ovary and corpus luteum, and hormonal regulation of oogenesis. A. Female reproductive organs shown from the posterior. B. Section through a primate ovary. C. Primordial and primary follicles shown at higher magnification than in part B. D. Preantral follicle shown at higher magnification than in part B. E. Graafian follicle shown at higher magnification than in part B. F. Section of a corpus hemorrhagicum. The asterisk indicates the central clot. Two corpora albicantia also are shown. G. Corpus luteum of menstruation shown at higher magnification than in part A. H. Interactions of hypothalamic, pituitary, and ovarian hormones that regulate follicle maturation during a typical 28-day ovarian cycle.