Helicine arteries of penis
| Helicine arteries of penis | |
|---|---|
 Diagram of the arteries of the penis. | |
| Details | |
| Identifiers | |
| Latin | arteriae helicinae penis |
| TA98 | A09.4.01.024 |
| TA2 | 4351 |
| FMA | 75410 |
| Anatomical terminology | |
The helicine arteries of penis are arteries in the penis. They are found in the corpora cavernosa penis.[1]
They are involved in the process of erection.[2]
Anatomy
On entering the cavernous structure from the deep artery of the penis the arteries divide into branches, which are supported and enclosed by the trabeculae. 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 Müller "helicine arteries".
Clinical significance
These arteries have two unique features: an intimal cushion and valves. Sympathetic stimulation maintains a tonic contractile state of the intimal cushion, smooth muscle lying in the center of the artery. This keeps the artery coiled and little blood flow occurs, instead routing to arteriovenous shunts to the deep dorsal vein. Parasympathetic stimulation removes the tonic state and allows vasodilation of the intimal cushion. Blood now pools in the corpus 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 of NO and is the primary target of Viagra. Viagra inhibits a key phosphodiesterase that reduces the effect of NO. NO binds to the receptors of the enzyme guanylate cyclase which results in increased levels of cGMP. cGMP has a very short half-life, and blocking PDE5 results in vasodilation even with small amounts of NO stimulation.
References
- ^ Böck P, Gorgas K (1977). "Morphology and histochemistry of helicine arteries in the corpora cavernosa penis of mice". Arch Histol Jpn. 40 (4): 265–81. PMID 597004.
{{cite journal}}: Unknown parameter|month=ignored (help) - ^ "helicine arteries of penis" at Dorland's Medical Dictionary
External links
This article incorporates text in the public domain from page 1251 of the 20th edition of Gray's Anatomy (1918)
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