Penis

The penis functions for both male voiding and sexual function. It comprises 3 cylinders - 2 corporal bodies (corpora cavernosus) on the top, lying side-by-side, and the spongial body (corpus spongiosus) housing the urethra beneath. The spongial tissue expands at the end to become the glans, or head, of the penis. The prepuce, or foreskin, is the redundant skin that covers the glans (unless surgically removed by circumcision). With voiding, the penile urethra becomes the conduit by which directed urine flow can occur. With sexual stimulation, the corporal bodies expand with blood, giving the penis increased length, girth, and hardness - an erection. Problems that can arise with the penis include - phimosis (scarring of the prepuce preventing retraction for hygiene), scarring in the urethra (called strictures), erectile dysfunction, erectile curvatures, etc.