Inabilitytoachieveormaintainanerectionistermederectile dysfunction (ED) andisonecauseofinfertilityinmen.MultiplefactorscanleadtoED,includinginsufficientandrogenproduction;neurovasculardamage(e.g.,fromdiabetesmellitus,spinalcordinjury);structuraldamagetothepenis,perineum,orpelvis;psychogenicfactors(e.g.,depression,performanceanxiety);andprescribedmedicationsandrecreationaldrugs,includingalcoholandtobacco.AmajordevelopmentinthetreatmentofsomeformsoferectiledysfunctionisuseofselectivecGMPphosphodiesteraseinhibitorsthatassistinmaintaininganerection(see
Fig.44.12B
There is no distinct andropause in men. However, as men age, gonadal sensitivity to LH decreases and androgen production drops. As this occurs, serum LH and FSH levels rise. Although sperm production typically begins to decline after age 50, many men can maintain reproductive function and spermatogenesis throughout life.
The female reproductive system is composed of the gonads, called ovaries, and the female reproductive tract, which includes the oviducts, uterus, cervix, vagina, and external genitalia.
The Ovary
The ovary is located within a fold of peritoneum called the broad ligament, usually close to the lateral wall of the pelvic cavity (
Fig. 44.13 ). Because the ovary extends into the peritoneal cavity, ovulated eggs briefly reside within the peritoneal cavity before they are captured by the oviducts.
The ovary is divided into an outer cortex and inner medulla (
Fig. 44.14 ). Neurovascular elements innervate the medulla of the ovary. The cortex of the ovary is composed of a densely cellular stroma. Within this stroma reside the ovarian follicles (see
Fig. 44.14, F ), which contain a primary oocyte surrounded by follicle cells. The cortex is covered by a connective tissue capsule, the tunica albuginea, (tactile, visual, auditory, psychic)
Collapse of venous return from cavernous spaces
Contraction of muscles around base of penis • Fig. 44.12 A, Arrangement of the vasculature and cavernous tissue within the penis. During the flaccid state, blood flow into the cavernous spaces is limited by contraction of the helicine arteries. B, Outline of neurovascular events leading to penile erection. (A, From Bhasun S et al. In: Larsen P et al [eds]. Williams Textbook of Endocrinology. 10th ed. Philadelphia: Saunders; 2003.)
CHAPTER 44 The Male and Female Reproductive Systems 799