Which statement best describes peristaltic waves?

Which statement best describes peristaltic waves?

• A. Segmental contractions that mix chyme
• B. Mechanical digestion in the mouth
• C. Wave-like motions with a movement from the upper to the lower GI system
• D. Absorption of water in the colon

Answer: (C)

Peristaltic waves are wave-like, coordinated contractions of GI smooth muscle that move contents along the tract from the upper to the lower portions. This propulsion advances the bolus through the GI system, a process called peristalsis, driven by sequential constriction and relaxation that pushes material forward. The best description—wave-like motions with movement from the upper to the lower GI system—captures this propulsive, forward-moving action. Segmental contractions described in the other option mix chyme rather than propel it forward, which is why they don’t fit peristalsis. Mechanical digestion in the mouth is chewing, not propulsion along the tract. Absorption of water in the colon concerns mucosal absorption, not the wave-like propulsion described by peristalsis.

Peristaltic waves are wave-like, coordinated contractions of GI smooth muscle that move contents along the tract from the upper to the lower portions. This propulsion advances the bolus through the GI system, a process called peristalsis, driven by sequential constriction and relaxation that pushes material forward. The best description—wave-like motions with movement from the upper to the lower GI system—captures this propulsive, forward-moving action. Segmental contractions described in the other option mix chyme rather than propel it forward, which is why they don’t fit peristalsis. Mechanical digestion in the mouth is chewing, not propulsion along the tract. Absorption of water in the colon concerns mucosal absorption, not the wave-like propulsion described by peristalsis.