Erectile tissue is any tissue that is capable of stiffening or engorging with blood. During sexual arousal, sexual erectile tissue experiences increased blood flow and becomes engorged with blood, enlargening and/or stiffening.
Erectile tissue is found in the male penis, the female vagina and clitoris, and the nipples of both men and women.
The male penis is composed of three compartments: one along each side (the corpus cavernosum; plural, cavernosa) and the central compartment (the corpus spongiosum). The corpus spongiosum, which surrounds the urethra, does not experience significant engorgement. When sexual arousal occurs, a nerve reflex initiates increased blood flow to the corpora cavernosa, causing increased local blood flow. This process floods the cavernosa with blood, causing the penis to enlarge, stiffen, and become erect.
In women tissues in the vagina and clitoris contain corpora cavernosa that are responsive to nerve reflexes during sexual arousal. During such arousal, blood flow to the labia majora and labia minora is increased, the tissues become engorged with blood, and the labia flatten and open. The clitoris becomes enlarged and stiff in a manner identical to erection of the penis. The upper portion of the vagina expands and retracts the uterus and cervix, forming an enlarged space.
The nipples of both women and men are capable of erection. As muscles surrounding the nipple contract during sexual arousal, local blood vessels become engorged and the nipples become erect. Nipples also may become erect during breast-feeding, as a result of fear or excitement, or in response to cold temperatures.
Rathus, Spencer A.; Jeffrey S. Nevid; and Lois Fichner-Rathus, eds. 2005. "Male Sexual Anatomy and Physiology." In Human Sexuality in a World of Diversity. 6th edition. Boston: Pearson Allyn and Bacon.
Rathus, Spencer A.; Jeffrey S. Nevid; and Lois Fichner-Rathus, eds. 2005. "Female Sexual Anatomy and Physiology." In Human Sexuality in a World of Diversity. 6th edition. Boston: Pearson Allyn and Bacon.
Christine R. Rainey