Mass movement of the colon is best described as which of the following?

• A. Peristaltic movement
• B. Mass movement
• C. Segmental movement
• D. Diffusion

Answer: (B)

Mass movement represents a large-scale, powerful propulsion of colonic contents that sweeps fecal material from portions of the colon toward the rectum. It occurs episodically, often after meals due to the gastrocolic reflex, and can move a substantial amount of stool in a short period. This is distinct from segmental (haustral) movements, which mainly mix and slowly advance contents within a section of the colon, and from diffusion, which is a passive, non-contractile process. In practice, mass movement is the pattern that explains rapid, long-distance transit through the colon and can influence ostomy output timing after meals.