Defecation

:For the death metal band Defecation, see Defecation . Defecation is the act or process by which organisms eliminate solid or semisolid waste material from the digestive tract via the anus. Humans expel feces with a frequency varying from a few times daily to a few times weekly; sloths can go a week without expelling. Waves of muscular contraction known as peristalsis in the walls of the colon move fecal matter through the digestive tract towards the rectum. Undigested food may also be expelled this way; this process is called egestion.The rectum ampulla acts as a temporary storage facility for the unneeded material. As the rectal walls expand due to the material filling it, 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 the fecal matter may harden, resulting in constipation.When the rectum is full, an 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 push the feces out of the rectum. The internal and external anal sphincters allow the feces to be passed by muscles pulling the anus up over the exiting feces. During defecation the chest muscles, diaphragm, abdominal wall muscles, and pelvic diaphragm all exert pressure on the digestive tract and ventilation temporarily ceases as the lungs push the chest diaphragm down in order to exert pressure. Blood pressure rises throughout the body and the amount of blood pumped by the heart decreases. During this time, the body is effectively undergoing similar stresses to that of a valsalva maneuver. Death has been known to occur in cases where defecation causes the blood pressure to rise enough to cause the rupture of an aneurysm or to dislodge blood clots . Humans must consciously relax the external sphincter muscles to expel waste. The anal and urethal sphincter muscles are closely linked, and experiments by Dr. Harrison Weed at the Ohio State University Medical Center have shown that they can only be contracted together, not individually, and that they both show relaxation during urination. This explains why defecation is frequently accompanied with urination.Defecation may be involuntary or under voluntary control. Young children learn voluntary control through the process of toilet training. Once trained, loss of control causing fecal incontinence may be caused by physical injury , intense fright, inflammatory bowel disease, impaired water absorption in the colon , and psychological or neurological factors. The positions and modalities of defecation are culture-dependent. In some regions of the world, such as South Asia, East Asia and rural parts of the Middle East, it is customary to squat , while in most of the Western World sit-down toilets are used. The anus and buttocks may be cleansed with toilet paper or similar paper products. In some cultures water is also used . In Japan, some toilets known as washlets are designed to wash and dry the anus of the user after defecation. (From the Wikpedia article Defecation.)

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Recent Publications on Defecation:
Sparganosis presenting as radiculalgia at the conus medullaris. A 26-year-old female presented with severe lumbodorsal pain and...	12th July, 2008	Department of Neurosurgery, Changzheng Hospital, Second Military Medical	Clin Neurol Neurosurg. 2008 Jul 8;. DOI Direct Link
Transperineal Microwave Thermoablation in Patients with Obstructive Benign Prostatic Hyperplasia: A Phase I Clinical Study with a New Mini-Choked Microwave Applicator. Purpose: To evaluate the tolerability and safety of a newly designed probe...	11th July, 2008	Department of Urology, University of Florence, Florence, Italy.	J Endourol. 2008 Jul 9;. DOI Direct Link
Prolapsed uterus with huge rectocele and omentocele following cervical amputation: a rare and unusual case presentation. Pelvic organ prolapse is a common condition whose incidence is increasing....	8th July, 2008	Department of Obstetrics and Gynaecology, BP Koirala Institute of Health	Kathmandu Univ Med J (KUMJ). 2006 Jan-Mar;4(1):89-93.
[Prune Belly syndrome: Epidemiologic, clinic and therapeutic aspects.] Prune Belly syndrome (PBS) is a rare complex malformation with male...	8th July, 2008	Service d'urologie-andrologie, CHU Aristide-Le-Dantec, babacar diao, B.P.	Prog Urol. 2008 Jul;18(7):470-4. Epub 2008 Jun 2. DOI Direct Link
Clinical Presentation and Patterns of Slow Transit Constipation Do Not Predict Coexistent Upper Gut Dysmotility. Background Slow transit constipation (STC) is associated with upper...	5th July, 2008	Centre for Academic Surgery (GI Physiology Unit), Barts and The London	Dig Dis Sci. 2008 Jul 4;. DOI Direct Link
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Defecation Clinical Trials:
A Randomized, Double-Blind, Placebo-Controlled Multicenter Study to Assess the Efficacy, Safety and Tolerability of Tegaserod 2 mg Bid vs Placebo in Patients With Chronic Constipation	Constipation;   Chronic Disease
Role of Routine Nasogastric Decompression After Subtotal Gastrectomy	Cancer of Stomach
Study Evaluating MOA-728 Oral for the Treatment of OIBD in Subjects With Chronic Non-Malignant Pain	Constipation Interventions: Drug: MOA-728;   Drug: Placebo
The Effect of Physiotherapy Treatment Following Gynaecological Surgery	Vaginal Hysterectomy,;   Pelvic Organ Prolapse Vaginal Surgery
Stapled TransAnal Rectal Resection (STARR): Clinical and Radiological Outcome	Obstructed Defecation Syndrome (ODS)
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Defecation Patents:
US Patent No.	Title
7210609	Stapling apparatus having a curved anvil and driver
7249570	Disposable nonskid absorbent pad
7250173	Use of parasitic biological agents for prevention and control of autoimmune diseases
7250445	Anti-oxidant suppository for treating radiation proctopathy and other anorectal disorders
7258879	Food product and process for manufacturing same
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