How an Erection Works

The physiology of an erection

So let’s talk about the physiology of erection; how an erection happens. All erections start in the brain first, with the limbic system. This is the part of the brain that’s kind of subconscious, kind of conscious, that controls libido, the “wowzah.” There’s a stimulus in there, which is far too complex for me to talk about, that then goes down the parasympathetic nervous system.

The nervous system and erections

This is part of the autonomic nervous system. These are nerves that you don’t directly control, that control your bodily functions for you, so you can think about other things. This goes down, and what it does is it starts to vasodilate the pudendal artery. This is the artery that goes in—that feeds into the penis from the internal iliac arteries of the pelvis. There are a pair of them on either side. This increased inflow into the penis.

Arteries and veins working for erections

It eventually ends in little spiral-shaped arteries called helicine arteries that line two cavernous sinuses. They’re called that because they’re basically just big veins on either side of the penis called the corpora cavernosa, or cavernous bodies. These fill with blood. As they fill with blood under the increased inflow from the helicine arteries, right, the veins leading out of what’s called the emissary veins of the penis, emissary mean going from, they get tamponaded off under the hydraulic pressure and you basically have an expansion of this venous sinus inside a tough layer of fascia or connective tissue called the tunica albuginea, or white layer. This white layer of collagen is the thickest and strongest connective tissue of the body. It fills and then you have basically hydraulic action—you have an erection.

Blood inflow and erectile dysfunction

When you’re done, which sometimes can be too soon for some of us, the helicine arteries start to constrict, the pudendal artery starts to constrict, and then you have decreased inflow. As the inflow decreases, then the emissary veins open up and you have outflow of the blood and you have a loss of that rigidity, what we call, scientifically, tumescence.


So basically, the arteries open up to allow blood flow in, veins close down under hydraulic pressure to prevent outflow. You have the erection until you don’t.

Eddie by Giddy for Erectile Dysfunction

Eddie is an FDA Registered Class II Medical Device designed to treat erectile dysfunction and provide an increase in sexual performance. To try Eddie, follow this link.

Pin It on Pinterest