Facts About Male Sex Organ

The blood supply of the penis comes from a main blood vessel that goes down the back of the body called the aorta. The aorta then branches to an internal and external iliac artery, and finally a pudendal artery passes underneath the pelvic bone and terminates in the common penile artery. When sitting and especially when riding a bicycle, a man can cut off blood circulation to this common penile artery. When this artery is damaged, arterial insufficiency and subsequent erectile dysfunction occur. A cavernosal artery supplies blood into each of the erectile bodies of the penis.

The blood supply to the glans, or head, of the penis is part of a separate system. It is for this reason that men can achieve an erection without swollen glans, such as in conditions known as priapism. This is also true for men who have penile implants; the glans or head of the penis will not become enlarged.

The underlying mechanism of an erection is the corporo-veno-occlusive mechanism. When the veins cannot become compressed or blocked, an erection cannot be maintained. Without this very sensitive mechanism, blood leaks prematurely from the penis and produces the loss of an erection. This type of erectile dysfunction is called a venous leak.

The nervous system of the penis is involved with both the creation and maintenance of an erection as well as an ejaculation. The most numerous sensory nerves are located on the head, or glans, of the penis. To achieve an erection it takes multiple input from numerous areas of both the brain and the spinal cord. The first part of a penile erection is controlled by the brain, known as a psychogenic erection. This occurs under any type of mental or erotic stimulation. Penile erections can also be caused by friction of the skin of the penis alone. This is known as a reflexogenic erection, which commonly occurs among men who have had damage to the spinal cord and who are unable to get an erection unless physically stimulated.