Defecation

defecation

 or bowel movement

Elimination of feces from the digestive tract. Peristalsis moves feces through the colon to the rectum, where they stimulate the urge to defecate. The rectum shortens, pushing the feces into the anal canal, where internal and external sphincters allow them to be passed or retained. Chest, abdominal, and pelvic muscles are used to pass them. Long delay of defecation causes constipation and hardened feces. See also diarrhea, incontinence.

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defecation [‚def·ə′kā·shən]

(chemical engineering)

Industrial purification, or clarification, of sugar solutions.

(physiology)

The process by which fecal wastes that reach the lower colon and rectum are evacuated from the body.

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Defecation 

(biological), the discharge from the digestive tract of food remnants unassimilated by the body. In mammals and man, the term refers to the evacuation of the fecal mass from the large intestine. In defecation, the sphincters that close the rectum are reflexively relaxed, and the feces are discharged by peristaltic movements of the large intestine and the rectum. The center for the defecation reflex is in the lumbar region of the spinal cord. Voluntary influences that excite or inhibit defecation come from the brain.