Urethra

From Wikipedia, the free encyclopedia

This article needs additional citations for verification. Please help improve this article by adding reliable references. Unsourced material may be challenged and removed. (June 2007)

Urethra
Female anatomy. (Urethra labeled at bottom left.)
Latin	Female urethra: urethra feminina Male urethra: urethra masculina
Gray's	subject #256 1234
Precursor	Urogenital sinus
MeSH	urethra
Dorlands/Elsevier	u_03/12838693

In anatomy, the urethra (from Greek ουρήθρα - ourethra) is a tube which connects the urinary bladder to the outside of the body. The urethra has an excretory function in both sexes to pass urine to the outside, and also a reproductive function in the male, as a passage for semen.

The external urethral sphincter is a striated muscle that allows voluntary control over urination.

Anatomy

Female urethra

In the human female, the urethra is about 1 1/2-2 inches (3-5 cm) long and opens in the vulva between the clitoris and the vaginal opening, extending from the internal to the external urethral orifice. It is placed behind the symphysis pubis, embedded in the anterior wall of the vagina, and its direction is obliquely downward and forward; it is slightly curved with the concavity directed forward. Its lining is composed of stratified squamous epithelium, which becomes transitional near the bladder. The urethra consists of three coats: muscular, erectile, and mucous, the muscular layer being a continuation of that of the bladder. Between the superior and inferior fascia of the urogenital diaphragm, the female urethra is surrounded by the Sphincter urethae. Somatic innervation of the external urethral sphincter is supplied by the pudendal nerve. The uro-genital sinus may be divided into three component parts. The first of these is the cranial portion which is continuous with the allantois and forms the bladder proper. The pelvic part of the sinus forms the prostatic urethra and epithelium as well as the membranous urethra and bulbo urethral glands in the male and the membranous urethra and part of the vagina in females.

Sexual physiology

The male urethra is the conduit for semen during sexual intercourse. It also serves as a passage for urine to flow.

See also

• Perineal urethra
• Vulvovaginal health
• Urethral sponge
• G-spot
• Urethral sounding
• Urethrotomy
• External urethral orifice
• Internal urethral orifice

Additional images

Urinary system

Muscles of the female perineum.

Transverse section of the penis.

External links

• Histology at KUMC epithel-epith07 "Male Urethra"