Rectum
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220679258
2008-06-21T01:15:11Z
Spinningspark
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/* See also */ I don't think conic sections will help you in those regions - only hyperbolically.
{{Cleanup|date=December 2007}}
{{refimprove|date=April 2008}}
{{Infobox Anatomy |
Name = Rectum|
Latin = |
GraySubject = 249 |
GrayPage = 1183 |
Image = Anorectum.gif |
Caption = Anatomy of the anus and rectum |
Image2 = Gray1077.png |
Caption2 = The posterior aspect of the rectum exposed by removing the lower part of the sacrum and the coccyx. |
Precursor = [[Hindgut]] |
Artery = [[superior rectal artery ]](1st two-thirds of rectum), [[middle rectal artery ]](last third of rectum) |
Vein = [[superior rectal veins]], [[middle rectal veins]] |
Nerve = [[inferior anal nerves]], [[inferior mesenteric ganglia]]<ref>{{GeorgiaPhysiology|6/6ch2/s6ch2_30}}</ref> |
Lymph = [[inferior mesenteric lymph nodes]], [[pararectal lymph nodes]], [[internal iliac lymph nodes]] |
MeshName = Rectum |
MeshNumber = A03.556.124.526.767 |
DorlandsPre = r_05 |
DorlandsSuf = 12697487 |
}}
The '''rectum''' (from the Latin ''rectum intestinum'', meaning ''straight intestine'') is the final straight portion of the [[large intestine]] in some [[mammal]]s, and the [[Gastrointestinal tract|gut]] in others, terminating in the [[anus]]. The human rectum is about 12 cm long. At its commencement its caliber is similar to that of the [[sigmoid colon]], but near its termination it is dilated, forming the [[rectal ampulla]].
== Role in human defecation ==
The rectum intestinum acts as a temporary storage facility for feces. As the rectal walls expand due to the materials filling it from within, stretch receptors from the [[nervous system]] located in the rectal walls stimulate the desire to [[defecation|defecate]]. If the urge is not acted upon, the material in the rectum is often returned to the [[Colon (anatomy)|colon]] where more water is absorbed. If defecation is delayed for a prolonged period, [[constipation]] and hardened feces results.
When the rectum becomes 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 [[peristalsis|peristaltic wave]]s propel the feces out of the rectum. The internal and external [[sphincter]] allow the feces to be passed by muscles pulling the anus up over the exiting feces.
==Medical procedures==
For the diagnosis of certain [[ailment]]s, a [[rectal exam]] may be done.
[[Suppository|Suppositories]] may be inserted into the rectum as a [[route of administration]] for [[medicine]].
The [[endoscopy|endoscopic]] procedures [[colonoscopy]] and [[sigmoidoscopy]] are performed to diagnose diseases such as [[cancer]].
===Temperature taking===
[[Body temperature]] can also be taken in the rectum. Rectal temperature can be taken by inserting a [[mercury thermometer]] for 3 to 5 minutes, or a digital [[thermometer]] until it "beeps", not more than 25 mm (1 inch) into the rectum via the [[anus]]. Due to recent concerns related to [[mercury poisoning]], the use of mercury thermometers is outlawed. Normal rectal temperature generally ranges from 36 to 38 °C (97.6 to 100.4 °F) and is about 0.5 °C (1 °F) above oral (mouth) temperature and about 1 °C (2 °F) above [[axillary]] ([[armpit]]) temperature.
Many [[pediatrics|pediatricians]] recommend that parents take [[infants]] and [[toddler]]'s temperature in the rectum for two reasons:
* (1) Rectal temperature is the closest to core body temperature and in children that young, accuracy is critical.
* (2) Younger children are unable to cooperate when having their temperature taken by mouth (oral) which is recommended for children, ages 6 and above and for adults.
In recent years, the introduction of ear (tympanic) thermometers and changing attitudes on [[privacy]] and [[modesty]] have led some parents and doctors to discontinue taking rectal temperatures.
== Sexual stimulation ==
Due to the proximity of the anterior wall of the rectum to the [[vagina]] in females or to the [[prostate]] in males and the shared nerves thereof, rectal [[stimulation]] or penetration can result in [[sexual arousal]]. For further information on this aspect, see [[anal sex]].
==Additional images==
<gallery>
Image:Illu repdt female.jpg|Organs of the [[Sex organ|female reproductive system]].
Image:Gray403.png|Median sagittal section of pelvis, showing arrangement of fasciæ.
Image:Gray539.png|The arteries of the pelvis.
Image:Gray1082.png|Section of [[mucous membrane]] of human rectum. X 60.
Image:Gray1083.png|The [[blood vessel]]s of the rectum and anus.
Image:Gray1228.png|Median sagittal section of male pelvis.
Image:Gray1230.png|Median sagittal section of female pelvis.
Image:WeiblichesBeckenMedian.gif|Sagittal section of the lower part of a female trunk, right segment.
Image:Penis.svg|The rectum can be seen on the left of this illustration.
Image:Rectum.JPG|Cross section microscopic shot of the rectal wall.
</gallery>
==See also==
* [[Gastrointestinal tract]]
* [[Rectal prolapse]]
* [[Pectinate line]]
* [[Murphy drip]]
==References==
{{reflist}}
==External links==
* {{ViennaCrossSection|pembody/body15a}}
* {{ViennaCrossSection|pelvis/pelvis-e12-15}}
* {{SUNYAnatomyImage|7|8|08}}
* {{SUNYAnatomyLabs|43|11|01|01}} - "The Female Pelvis: The Rectum"
{{digestive_system}}
{{human anatomical features}}
{{sex}}
[[Category:Digestive system]]
[[Category:Pelvis]]
[[ar:مستقيم]]
[[cs:Konečník]]
[[da:Endetarm]]
[[de:Mastdarm]]
[[dv:ފުރަގަސް ފަރާތް]]
[[es:Recto]]
[[eo:Rektumo]]
[[fr:Rectum]]
[[io:Rektumo]]
[[id:Rektum]]
[[is:Endaþarmur]]
[[it:Retto]]
[[he:חלחולת]]
[[jv:Rektum]]
[[la:Rectum]]
[[lt:Tiesioji žarna]]
[[nl:Endeldarm]]
[[ja:直腸]]
[[no:Endetarmen]]
[[pl:Odbytnica]]
[[pt:Recto]]
[[ro:Rect]]
[[ru:Прямая кишка человека]]
[[simple:Rectum]]
[[sk:Konečník (stavovce)]]
[[sl:Danka]]
[[fi:Peräsuoli]]
[[sv:Ändtarm]]
[[tl:Tumbong]]
[[te:పురీషనాళము]]
[[zh:直肠]]