AskDefine | Define rectum

Dictionary Definition

rectum n : the terminal section of the alimentary canal; from the sigmoid flexure to the anus [also: recta (pl)]

User Contributed Dictionary

English

Etymology

From Latin rectus (meaning straight). See right

Noun

  1. The terminal part of the large intestine through which feces pass.

Translations

Rectum

See also

Extensive Definition

The rectum (from the Latin rectum intestinum, meaning straight intestine) is the final straight portion of the large intestine in some mammals, and the 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 defecate. If the urge is not acted upon, the material in the rectum is often returned to the 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 peristaltic waves 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 ailments, a rectal exam may be done.
Suppositories may be inserted into the rectum as a route of administration for medicine.
The 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 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

Image:Illu repdt female.jpg|Organs of the female reproductive system. æ. mucous membrane of human rectum. X 60. blood vessels of the rectum and anus.

References

External links

  • - "The Female Pelvis: The Rectum"
rectum in Arabic: مستقيم
rectum in Czech: Konečník
rectum in Danish: Endetarm
rectum in German: Mastdarm
rectum in Dhivehi: ފުރަގަސް ފަރާތް
rectum in Spanish: Recto
rectum in Esperanto: Rektumo
rectum in French: Rectum
rectum in Ido: Rektumo
rectum in Indonesian: Rektum
rectum in Icelandic: Endaþarmur
rectum in Italian: Retto
rectum in Hebrew: חלחולת
rectum in Javanese: Rektum
rectum in Latin: Rectum
rectum in Lithuanian: Tiesioji žarna
rectum in Dutch: Endeldarm
rectum in Japanese: 直腸
rectum in Norwegian: Endetarmen
rectum in Polish: Odbytnica
rectum in Portuguese: Recto
rectum in Romanian: Rect
rectum in Russian: Прямая кишка человека
rectum in Simple English: Rectum
rectum in Slovak: Konečník (stavovce)
rectum in Slovenian: Danka
rectum in Finnish: Peräsuoli
rectum in Swedish: Ändtarm
rectum in Tagalog: Tumbong
rectum in Telugu: పురీషనాళము
rectum in Chinese: 直肠

Synonyms, Antonyms and Related Words

abdomen, anus, appendix, blind gut, bowels, brain, cecum, colon, duodenum, endocardium, entrails, foregut, giblets, gizzard, guts, heart, hindgut, innards, inner mechanism, insides, internals, intestine, inwards, jejunum, kidney, kishkes, large intestine, liver, liver and lights, lung, midgut, perineum, pump, pylorus, small intestine, spleen, stomach, ticker, tripes, vermiform appendix, viscera, vitals, works
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