Peristaltic movement in the colon primarily does what?

• A. Absorbs water and electrolytes
• B. Initiates defecation reflex
• C. Pushes fecal material through the colon
• D. Mixes chyme with gastric secretions

Answer: (C)

Propulsive movement is the key role of colon peristalsis. The colon uses slow, coordinated peristaltic waves to push fecal material forward toward the rectum, enabling eventual elimination. While the colon does absorb water and electrolytes and also performs mixing movements (haustral contractions) to enhance contact with the mucosa, those actions are about absorption and mixing, not propulsion. The defecation reflex is triggered by rectal distension after stool reaches the rectum, not initiated by peristalsis in the colon. Mixing chyme with gastric secretions happens in the stomach, not the colon. So the primary effect of colonic peristalsis is moving stool along the length of the colon toward the rectum.