Corpus cavernosum penis
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2008-04-22T13:40:09Z
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{{Infobox Anatomy |
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Latin = corpus cavernosum penis |
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Image = Gray1155.png |
Caption = Transverse section of the penis. |
Image2 = Gray1154.png |
Caption2 = The constituent cavernous cylinders of the penis. |
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DorlandsPre = c_56 |
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The '''corpus cavernosum penis''' is one of a pair of sponge-like regions of [[erectile tissue]] which contain most of the [[blood]] in the male [[penis]] during [[erection]]. This is [[homology (biology)|homologous]] to the [[Corpus cavernosum clitoridis|corpus cavernosum clitoridis]] in the female. The term literally means "cave-like body" (plural: ''corpora cavernosa'').
The two corpus cavernosa and [[corpus spongiosum penis|corpus spongiosum]] (also known as the corpus cavernosum urethrae in older texts and in the diagram to the right) are three expandable erectile tissues along the length of the [[penis]] which fill with [[blood]] during [[erection]]. The two corpora cavernosa lie along the penis shaft, from the pubic bones to the head of the penis, where they join. These formations are made of a sponge-like tissue containing irregular blood-filled spaces lined by [[endothelium]] and separated by [[connective tissue]] [[Septum|septa]]. The corpus spongiosum is one smaller region along the bottom of the penis, which contains the [[urethra]] and forms the glans penis.
In some circumstances, release of [[nitric oxide]] precedes relaxation of muscles in the corpora cavernosa and corpus spongiosum. The spongy tissue fills with blood, from arteries down the length of the penis. A little blood enters the corpus spongiosum; the remainder engorges the corpora cavernosa, which expand to hold 90% of the blood involved in an erection, increasing both in length and in diameter. The function of the corpus spongiosum is to prevent compression of the urethra during erection.
Blood can leave the erectile tissue only through a drainage system of veins around the outside wall of the corpus cavernosum. The expanding spongy tissue presses against a surrounding dense tissue ([[tunica albuginea]]) constricting these veins, preventing blood from leaving. The penis becomes rigid as a result. The [[glans penis]], the expanded cap of the corpus spongiosum, remains more malleable during erection because its tunica albuginea is much thinner than elsewhere in the penis.
==Additional images==
<gallery>
Image:Illu penis.jpg|Structure of the penis
Image:Gray543.png|The deeper branches of the internal pudendal artery.
Image:Gray588.png|The penis in transverse section, showing the bloodvessels.
Image:Gray1136.png|Male pelvic organs seen from right side.
Image:Gray1158.png|Diagram of the arteries of the [[penis]].
</gallery>
==External links==
* {{SUNYAnatomyLabs|42|st|11|02}} - "The Male Perineum and the Penis: Penis"
* {{eMedicineDictionary|corpus+cavernosum+penis}}
* {{eMedicineDictionary|corpus+cavernosum+urethrae}}
[[Category:Andrology]]
[[Category:Penis]]
{{Male reproductive system}}
[[bg:пещеристо тяло]]
[[cs:Topořivé těleso]]
[[fr:Corps caverneux]]
[[it:Corpo cavernoso]]
[[ja:海綿体]]
[[pl:Ciała jamiste]]
[[pt:Corpo cavernoso]]
[[simple:Corpus cavernosum]]
[[zh:海綿體]]