The Defecation Reflex

Multiple Choice

The defecation reflex

A) is initiated when mass movements force fecal material into the rectum, stimulating stretch receptors in the rectal wall
B) involves relaxation of the internal anal sphincter
C) involves contraction of the sigmoid colon and rectum
D) can be overridden by voluntary contraction of the external anal sphincter
E) has all of the above characteristics