Rectum 25669 220679258 2008-06-21T01:15:11Z Spinningspark 3727527 /* 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]]