| Helicine arteries of penis | |
|---|---|
 Diagram of the arteries of the penis. | |
| Details | |
| Identifiers | |
| Latin | arteriae helicinae penis |
| TA98 | A09.4.01.024M |
| TA2 | 4351 |
| FMA | 75410 |
| Anatomical terminology | |
Thehelicine arteries of penis arearteries in thepenis. They are found in thecorpora cavernosa penis.[1]
They are involved in the process oferection.[2]
On entering the cavernous structure from thedeep artery of the penis the arteries divide into branches, which are supported and enclosed by thetrabeculae. Some of these arteries end in a capillary net-work, the branches of which open directly into the cavernous spaces; others assume a tendril-like appearance, and form convoluted and somewhat dilated vessels, which were named by Rosenmüller "helicine arteries".
These arteries have two unique features: an intimal cushion and valves. Sympathetic stimulation maintains atonic contractile state of theintimal cushion, a smooth muscle lying in the center of the artery. This keeps the artery coiled, and little blood flow occurs, instead routing toarteriovenous shunts to thedeep dorsal vein. Parasympathetic stimulation removes the tonic state and allows vasodilation of the intimal cushion. Blood now pools in thecorpora cavernosa, resulting in erection. The valves prevent backflow in the now-tortuous route through the cavernosa.
This parasympathetic relaxation response is mediated by a release ofnitric oxide (NO). NO binds to the enzymeguanylate cyclase, which results in increased levels ofcyclic guanosine monophosphate (cGMP). cGMP in turn triggers relaxation of thesmooth muscle and results in dilation of blood vessels. This signal is terminated when cGMP is broken down by the enzymecGMP specific phosphodiesterase type 5 (PDE5), the enzyme that is targeted bysildenafil and other drugs that treat erectile dysfunction. By preventing PDE5 from breaking down cGMP, the effects of NO are amplified and vasodilation occurs, thus resulting in increasedpenile erection.
This article incorporates text in thepublic domain frompage 1251 of the 20th edition ofGray's Anatomy(1918)
