- Human anus
The human Anus (from
Latin"ānus" "ring (circle)cite book | last = Martim de Albuquerque | first = | title = Notes and Queries | publisher = Oxford University Press | date= 1873 | location = Original from the University of Michigan | pages = Page 119 | url = http://books.google.com/books?id=FEn-C_BzRdMC&pg=PA119&dq=latin+butthole+ring&as_brr=1&ie=ISO-8859-1 | doi = | id = ] cite book | coauthors = Edward O'Reilly, John O'Donovan | title = An Irish-English Dictionary | publisher = J. Duffy | date= 1864 | location = Original from Oxford University | pages = Page 7 | url = http://books.google.com/books?id=dX8NAAAAQAAJ&pg=PA7&dq=latin+butthole+ring&as_brr=1&ie=ISO-8859-1 | doi = | id = ] ) is the external opening of the rectum. Like other animals, its closure is controlled by sphincter muscles. Fecesare expelled from the body through the anus during the act of defecation, the primary function of the anus.
The anus plays a role in sexuality, though attitudes towards
anal sexvary; it is illegal in some countries.Fact|date=April 2008 The anus is also the site of potential infections and other conditions including cancer. The subject is often considered a taboopart of the body, and it is known by a large number of usually vulgar slangterms. The traditional polite synonym for anus was , though this euphemismis rarely heard now that medical terms are widely acceptable.
Role in defecation
Intra-rectal pressure builds as the
rectumfills with feces, pushing the feces against the walls of the anal canal. Contractions of abdominal and pelvic floor muscles can create intra-abdominal pressure which further increases intra-rectal pressure. The internal anal sphincter(an involuntary muscle) responds to the pressure by relaxing, thus allowing the feces to enter the canal. The rectum shortens as feces are pushed into the anal canal and peristaltic waves push the feces out of the rectum. Relaxation of the internal and external anal sphincters allows the feces to exit from the anus, finally, as the levator animuscles pull the anus up over the exiting feces.
To prevent diseases of the anusFact|date=June 2007 and to promote general hygiene, humans often clean the exterior of the anus after emptying the bowels. A rinse with water from a
bidetor a wipe with toilet paperare often used for this purpose.
Role in sexuality
The anus has a relatively high concentration of nerve endings and is an
erogenous zone. Sigmund Freud's theory of psychosexual development, for example, described an anal stage, hypothesizing that toddlers derive pleasure from retaining and expelling feces. This is the source of the term "anal" and the derived, derogatoryvulgarism "anal-retentive".
Anal intercourse can be pleasurable for both the insertive partner and the receptive partner. For the receptive partner, pleasure from anal intercourse is also thought to be related to the shared wall between the rectum and the
vagina(for females) as well as the G-spotor prostate(for males). For the insertive partner, the tightness of the anus is often said to be a source of pleasure in penetrative anal sex.Anal intercourse, sometimes referred to as sodomyor buggery, is a human sexual activity, but is considered tabooin a number of moral systems, and it has been, and in some jurisdictions continues to be, a crime carrying severe punishment.
Anal sexual activity need not include penetration. The anus also plays an important role in
facesitting, coprophiliaand anilingus.
Anal stretching can stimulate the nerves around the anus and can be considered pleasurable. Care must be taken to maintain elasticity.
Lubricant is widely regarded as a necessity while performing anal sex.
puberty, as testosterone triggers androgenic hairgrowth on the body, pubic hair begins to appear around the anus. Although initially sparse, it fills out by the end of puberty, if not earlier.
Hygiene is important for good anal health and anal sex. 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.
Care should be taken not to strip the anus of natural oils that keep the skin around the opening supple and elastic.
Penetration with a penis or
sex toycan irritate or tear the inside of the anus. Lubrication is often recommended to ease penetration. The risk of injury to the anal sphincter should be a concern. Similarly if the anus is torn, this can occasionally cause a fistula formation which can not only cause fecal leaking, but also can be very difficult to treat. Kegel exercises can improve the tone of the outer sphincter muscle [cite web|url=http://www.continence-foundation.org.uk/publications/pdfs/Sphincter%20Exercises%209.PDF|title=The Continence Foundation - Sphincter Exercises to Aid Bowel Control|accessdate=2008-05-14] .
Shaving, trimming, depilatory (hair removal), or
Brazilian waxingcan clear the perineum of hair. Anal bleachingis a process in which the anus and perineum, which may darken with puberty depending on individual genetics, is lightened for a more youthful appearance. This practice has been linked to skin cancer, and other health problems.
anal piercingis rare because it may interfere with the function of the anus. However, surface piercings of the perineum are easier to care for and much more common.
Diseases of the anus include
anal cancer, abscess, warts, fistula, anal fissure, itching and hemorrhoid. The anus is also a frequent site of sexually transmitted infections. These benefit from medical intervention. Birth defectsof the anus include stenosisand imperforation. These benefit from surgical intervention.
anal sphincter( patulous anusin more severe cases) — caused by careless or sometimes necessarily sacrificial surgery in the perineal region or by rough/abrupt penetration in anal sex— can lead to flatusand/or fecal incontinence, chronic constipationand, ultimately, megacolon.
psychologythe Freudian term anal fixationis used.
Anal stage(Freudian psychosexual stage)
* Coccydynia (coccyx pain, tailbone pain)
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