A corpus cavernosum penis (singular) (from Latin, characterised by "cavities/ hollows" of the penis, : corpora cavernosa) is one of a pair of sponge-like regions of erectile tissue, which contain most of the

blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood is com ...

in the

penis A penis (; : penises or penes) is a sex organ through which male and hermaphrodite animals expel semen during copulation (zoology), copulation, and through which male placental mammals and marsupials also Urination, urinate. The term ''pen ...

of several animals during an

erection An erection (clinically: penile erection or penile tumescence) is a Physiology, physiological phenomenon in which the penis becomes firm, engorged, and enlarged. Penile erection is the result of a complex interaction of psychological, neural, ...

. It is homologous to the

corpus cavernosum clitoridis The corpus cavernosum of the clitoris is one of a pair of sponge-like regions of erectile tissue that engorge with blood during an erection. This is homologous to the corpus cavernosum of the penis. The term ''corpora cavernosa'' literally ...

in the female.

Structure

The corpora cavernosa are two expandable erectile tissues along the length of the penis, which fill with

during penile erection. The two corpora cavernosa lie along the penile shaft, from the pubic bones to the head of the penis, where they join. These formations are made of a sponge-like tissue containing trabeculae, irregular blood-filled spaces lined by

endothelium The endothelium (: endothelia) is a single layer of squamous endothelial cells that line the interior surface of blood vessels and lymphatic vessels. The endothelium forms an interface between circulating blood or lymph in the lumen and the r ...

and separated by septum of the penis. The male anatomy has no

vestibular bulbs In female anatomy, the vestibular bulbs, bulbs of the vestibule or clitoral bulbs are two elongated masses of erectile tissue typically described as being situated on either side of the vaginal opening. They are united to each other in front by a ...

, but instead a corpus spongiosum, a smaller region of erectile tissue along the bottom of the penis, which contains the

urethra The urethra (: urethras or urethrae) is the tube that connects the urinary bladder to the urinary meatus, through which Placentalia, placental mammals Urination, urinate and Ejaculation, ejaculate. The external urethral sphincter is a striated ...

and forms the

glans penis In male human anatomy, the glans penis or penile glans, commonly referred to as the glans, (; from Latin ''glans'' meaning "acorn") is the bulbous structure at the Anatomical terms of location#Proximal and distal, distal end of the human penis ...

Physiology

In some circumstances, release of

nitric oxide Nitric oxide (nitrogen oxide, nitrogen monooxide, or nitrogen monoxide) is a colorless gas with the formula . It is one of the principal oxides of nitrogen. Nitric oxide is a free radical: it has an unpaired electron, which is sometimes den ...

precedes relaxation of muscles in the corpora cavernosa and corpus spongiosum, in a process similar to female arousal. 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

, 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

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

. Image:Penis_cross_section.svg, Cross section of penis. File:Normal penis ultrasound.jpg,

Medical ultrasonography Medical ultrasound includes Medical diagnosis, diagnostic techniques (mainly medical imaging, imaging) using ultrasound, as well as therapeutic ultrasound, therapeutic applications of ultrasound. In diagnosis, it is used to create an image of ...

of a normal penis.

References

External links

* - "The Male Perineum and the Penis: Penis" {{Authority control Mammal male reproductive system Human penis anatomy

Structure

Physiology

Additional images

See also

References

External links