Anus
In anatomy, the anus (from Latin ānus "ring, anus") is the external opening of the rectum. Closure is controlled by sphincter muscles. Feces are expelled from the body through the anus during the act of defecation, which is the primary function of the anus. Most animals — from simple worms to elephants and humans — have a tubular gut, with a mouth at one end and an anus at the other.
The anus is often considered a taboo part of the body, and is also known by a large number of slang terms, which are generally considered vulgar and not used in polite speech.
Structure
The human anus is situated between the buttocks, posterior to the perineum. It has two anal sphincters, one internal, the other external. These hold the anus until time to defecate. One sphincter consists of smooth muscle and its action is involuntary; the other, striated muscle and voluntary. In many animals, the anus is surrounded by anal sacs.
Role in defecation
When the rectum is full the increase in intrarectal pressure forces the walls of the anal canal apart allowing the fecal matter to enter the canal. The rectum shortens as material is forced into the anal canal and peristaltic waves propel the feces out of the rectum. The internal and external sphincters of the anus allow the feces to be passed by muscles pulling the anus up over the exiting feces.
To prevent diseases of the anus and to promote general hygiene, humans often follow the action of the sphincter with a cleansing activity after emptying the bowels. A wash with a bidet or a wiping with toilet paper are often used to clear the anus of fecal matter.
Role in sexuality
Nacon, it's gonna be a fun night buddy! I thought you'd like this page, since you are a faggot! I bet you lick assholes all damn night you dirty whore! Wow you really want your ass stuffed right now don't you? You're probably gonna try to change this vandalism, but won't be able to for a while because you'll be too busy jerking off to the picture of this sphinxter you sick motherfucking faggot!
Maintenance
Hygiene is important for good anal health. Washing with a mild soap and water will keep the anus clean. Harsh soaps or wiping vigorously with toilet paper can irritate the skin around the anus, making it itchy or sore. Pinworms are sometimes the source of anal itching.
Penetration with a penis or sex toy can irritate or tear the inside of the anus. Lubrication is often recommended to ease penetration.
Kegel exercises can improve the tone of the outer sphincter muscle.
Cosmetics
Shaving, trimming, depilatory, or Brazilian waxing can clear the perineum of hair.
Anal bleaching is a relatively new West coast phenomenon where the perineum, which darkens over the years, is lightened for a more youthful appearance. In 2004 it was reported that actress Lara Flynn Boyle had her anus bleached for cosmetic purposes.
Anal piercing is among the more extreme piercings and usually interferes with the function of the anus.
Pathology
Anal cancer, abcess, warts, fistula, fissure, itching and hemorrhoids are among the diseases of the anus that benefit from medical intervention. Birth defects of the anus include stenosis and imperforation. The anus is also a frequent site of sexually transmitted infections.
See also
- WikiSaurus:anus — the WikiSaurus list of synonyms and slang words for the anus in many languages
- Arse
- Digestive system
- Anal masturbation
- Cloaca
- Flatulence
- Sodomy