A corpus cavernosum penis (singular) (literally "cave-like body" of the penis, plural corpora cavernosa) is one of a pair of sponge-like regions of
erectile tissue, which contain most of the
blood in the
penis during an
erection
An erection (clinically: penile erection or penile tumescence) is a physiological phenomenon in which the penis becomes firm, engorged, and enlarged. Penile erection is the result of a complex interaction of psychological, neural, vascular, ...
.
Such a
corpus is
homologous
Homology may refer to:
Sciences
Biology
*Homology (biology), any characteristic of biological organisms that is derived from a common ancestor
*Sequence homology, biological homology between DNA, RNA, or protein sequences
* Homologous chrom ...
to the
corpus cavernosum clitoridis
The corpus cavernosum of clitoris is one of a pair of sponge-like regions of erectile tissue of the clitoris in women. It is made of a sponge-like tissue that fills with blood during clitoral erection. This is homologous to the corpus cavernosum ...
in the female; the body of the
clitoris
The clitoris ( or ) is a female sex organ present in mammals, ostriches and a limited number of other animals. In humans, the visible portion – the glans – is at the front junction of the labia minora (inner lips), above the ope ...
that contains
erectile tissue in a pair of corpora cavernosa with a recognisably similar structure.
Anatomy
The two corpora cavernosa and
corpus spongiosum (also known as the ''corpus cavernosum urethrae'' in older texts and in the adjacent diagram) are three expandable erectile tissues along the length of the
penis, which fill with
blood during
penile 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
trabeculae, irregular blood-filled spaces lined by
endothelium and separated by
septum of the penis.
The male anatomy has no
vestibular bulbs, but instead a
corpus spongiosum, a smaller region along the bottom of the penis, which contains the
urethra and forms the
glans penis.
Physiology
In some circumstances, release of
nitric oxide
Nitric oxide (nitrogen oxide 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 denoted by a dot in its che ...
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
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
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.
Image:Penis_cross_section.svg, Cross section of penis.
File:Normal penis ultrasound.jpg, Medical ultrasonography
Medical ultrasound includes diagnostic techniques (mainly medical imaging, imaging techniques) using ultrasound, as well as therapeutic ultrasound, therapeutic applications of ultrasound. In diagnosis, it is used to create an image of internal ...
of a normal penis.
See also
*
Peyronie's disease
References
External links
* - "The Male Perineum and the Penis: Penis"
{{Authority control
Mammal male reproductive system
Human penis anatomy