Define peristalsis.

Define peristalsis.

• A. An automatic reflex to swallow
• B. The alternating contractions in the GI tract to move the bolus down or along the tract.
• C. Secretion of bile into the intestine
• D. Absorption of nutrients

Answer: (B)

Peristalsis is the coordinated, wave-like movement of GI smooth muscle that propels contents forward through the tract. It works through alternating contractions: the circular muscles behind the lump of food contract to squeeze it along, while the longitudinal muscles ahead relax to widen the path, and this sequence passes along the digestive tract as a traveling wave. This propulsion is involuntary and driven by the enteric nervous system, with swallowing triggering peristaltic waves in the esophagus and distension triggering waves further down. The best way to describe it is as the alternating contractions in the GI tract to move the bolus down or along the tract. Secretion of bile, absorption of nutrients, or a simple reflex to swallow each capture different functions and don’t define this movement pattern.

Peristalsis is the coordinated, wave-like movement of GI smooth muscle that propels contents forward through the tract. It works through alternating contractions: the circular muscles behind the lump of food contract to squeeze it along, while the longitudinal muscles ahead relax to widen the path, and this sequence passes along the digestive tract as a traveling wave. This propulsion is involuntary and driven by the enteric nervous system, with swallowing triggering peristaltic waves in the esophagus and distension triggering waves further down.

The best way to describe it is as the alternating contractions in the GI tract to move the bolus down or along the tract. Secretion of bile, absorption of nutrients, or a simple reflex to swallow each capture different functions and don’t define this movement pattern.