The rectum is the last straight portion of the colon in humans and some other mammals, and intestines in others. The adult human rectum is about 12 cm (4.7 inches) long, and starts at the rectosigmoid junction, the sigmoid end of the colon, at the level of the third sacral vertebra or sacral promontory depending on what definition is used. The caliber is similar to a sigmoid colon at the beginning, but dilates near termination, forming a rectal ampule. It ends at the level of the anorectal ring (the level of puborectal sling) or the dentate line, again depending on the definition used. In humans, the rectum is followed by an anal canal approximately 4 cm (1.6 inches) long, before the gastrointestinal tract ends on the anal threshold. The word rectum comes from the Latin rectum intestinum , which means straight intestine .
Video Rectum
Structure
The rectum is part of the lower digestive tract. The rectum is a continuation of the sigmoid colon, and connected to the anus. The rectum follows the shape of the sacrum and ends in an expanded section called rectum ampulla , where the stool is stored before its release through the anal canal. Ampula is a cavity, or an enlarged ductal end, shaped like a Roman ampoule.
Unlike other parts of the colon, the rectum has no taeniae coli.
The rectum connects with the sigmoid colon at S3 level, and connects with the anal opening while passing through the pelvic floor muscles.
Rectal support includes:
- The pelvic floor is formed by the levator ani muscle.
- Waldeyer Fascic
- Rectal lateral ligaments formed by condensation of the pelvic fascia
- The rektovesical fascia of the Denonvillers, which extend from the rectum behind to the seminal vesicles and the prostate in front.
- Peritoneum pelvis
- Perineal body
Microanatomy
Maps Rectum
Function
The rectum acts as a temporary storage place for feces. When the rectal wall expands due to the material that fills it from within, the stretching receptors of the nervous system located on the rectal wall stimulate the urge 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 from the stool. If bowel movements are delayed for a long time, constipation and stool results are hardened.
When the rectum becomes full, increased intrarectal pressure forces the anal canal wall to separate, allowing the faeces to enter the channel. The rectum is shorter because the material is forced into the anal canal and the peristaltic waves push the impurities out of the rectum. The internal and external sphincters allow the stool to be passed by the muscles that pull the anus up into the outstretched faeces.
Clinical interests
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For the diagnosis of certain diseases, rectal examination may be performed. These include faecal impaction, prostate cancer and benign prostate hypertrophy in men, faecal incontinence, and internal hemorrhoids.
Colonoscopy or sigmoidoscopy is an endoscopic form that uses a guided camera to see the rectum. It may have the ability to take a biopsy if necessary, and can be used to diagnose diseases such as cancer.
Body temperature can also be taken in the rectum. The rectal temperature may be taken by inserting a medical thermometer no more than 25 mm (1 inch) into the rectum through the anus. The mercury thermometer should be inserted for 3 to 5 minutes; the digital thermometer must remain inserted until it sounds. Normal rectal temperatures generally range from 36 to 38 Â ° C (96.8 to 100.4 ° F) and about 0.5 Â ° C (1 Â ° F) above oral temperature (mouth) and about 1 Â ° C (2%). Â ° F) above the armpit (armpit) temperature. In recent years, the introduction of non-invasive temperature taking methods including tympanic (ears) and forehead thermometers, and changing attitudes to privacy and courtesy have caused some parents and doctors to stop taking rectal temperatures.
Administrative route
By their definition, suppository is inserted, and the enema is injected, through the rectum. Both of these can be used for the delivery of drugs or to eliminate constipation; enema is also used for various other purposes, medical and other.
Constipation
One cause of constipation is the impaction of feces in the rectum, where stools are dry and hard formed. Manual evacuation is the use of gloved fingers to evacuate the feces from the rectum, and, after application of stool softeners, is used in acute constipation. It is also in the long-term management of the neurogenic intestine, most commonly seen in people with spinal cord injury or multiple sclerosis. Digital rectal stimulation, inserting a finger into the rectum, may be used to induce peristalsis in patients whose peristaltic reflex is inadequate to completely empty the rectum.
Disease
- Proctitis is inflammation of the anus and rectum.
- Rectal cancer, a subgroup of specialized colorectal cancers in the rectum.
- Rectal prolapse, refers to rectal prolapse to the anus or external area. This is usually caused by a weakened pelvic floor after delivery.
Other diseases
Other diseases of the rectum include:
- Ulcerative colitis, a form of inflammatory bowel disease that causes ulcers that affect the rectum. It may be episodic, for the life of a person. This can cause blood to appear in the stool. By 2014 the cause is unknown.
- In the context of mesenteric ischemia, the upper rectum is sometimes referred to as the Sudak's point and has a clinical interest as a waterway between the inferior mesenteric circulation of arteries and the internal iliac artery circulation through the middle rectal Artery, and thus susceptible to ischemia. Sudak is often referred to along with the Griffith point on the spleach curve as a watershed.
Society and culture
Sexual stimulation
Because the proximity of the anterior wall of the rectum to the vagina in a woman or prostate in a male, and joint nerve, rectal stimulation or penetration can lead to sexual arousal.
History
Etymology
The English rectum comes from a full Latin expression rectum intestinum . The English name straight gut really expresses the literal meaning of this expression, as Latin rectum means straight , and intestinum > means intestines . This Latin phrase is a translation of Ancient Greek ???????????? ???????, derived from ?????????, to make straight , and ???????, intestines , evidenced in the writings of the Greek physician Galen. During the anatomical investigation of the animal's corpse, Galen observed the rectum to be straight instead of curving as in humans. Expression ???????????? ??????? and the intestinal rectum is therefore not a proper description of the rectum in humans. Apeuthysmenon can be considered as Latinisation of ???????????? ??????? and euthyenteron have the same meaning (????? = straight).
See also
- Gastrointestinal tract
- Drops Murphy
- Pectinate rows
- Rectal prolapse
- Rectal Thermometry
References
- Henry Gray: Anatomy of the human body (Bartleby.com; Great Books Online).
- Eldra P. Solomon, Richard R. Schmidt, and Peter J. Adragna: Human Anatomy & amp; physiology , second edition. 1990 (Sunders College Publishing, Philadelphia). ISBN: 0-03-011914-6.
External links
- Blue Histology
- Cross-section image: pembody/body15a - Plastination Laboratory at Medical University of Vienna
- Cross-section image: pelvis-e12-15 - Plastination Laboratory at Vienna Medical University
- Anatomical image: 7808 in SUNY Downstate Medical Center
- Photo anatomy: 43: 11-0101 at SUNY Downstate Medical Center
Source of the article : Wikipedia
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