Physiology of an Erection

Achieving and maintaining an erection depends on a complex interaction of the body's nervous system and the vascular system in the penis. The following is a simplified explanation of how a male achieves and maintains an erection.

The erectile response typically begins in the brain. Responding to sexual stimulation, the brain initiates neurological response to increase blood flow in the corpus cavernosal arteries within the penis. With the increase in blood flow, the corpus cavernosum surrounding each artery and begins to fill with blood.