While doing sigmoidoscopy, if the rectum is inflated with gas, increased peristalsis is seen in
Whole colon
Proximal colon
Distal colon
Whole intestine
Defecation reflex - When the rectum is distended, a reflex propulsive movement from descending colon to rectum occurs. Along with that, the internal anal sphincter relaxes. The same happens when the rectum is distended by gas.