Homonym: Erection (Construction)
An erection is a physiological process in which the penis becomes firm and enlarged. This occurs when blood flows into the erectile tissues of the penis, often in response to sexual arousal or stimulation. The increased blood flow causes the penis to expand and harden, allowing for potential sexual intercourse.
Erections can also happen during sleep or without any sexual thoughts, known as nocturnal penile tumescence. Various factors, including hormones, nerves, and blood vessels, play a role in this process. Conditions affecting any of these systems can lead to difficulties in achieving or maintaining an erection, known as erectile dysfunction.