During endoscopy, a bolus of food residue is seen in the mid-oesophagus after a failed primary peristaltic wave. Minutes later, a peristaltic contraction begins at the point of distension and sweeps the residue downward. This response is called secondary peristalsis and is characterised by:

• A Initiation by local distension and mediation entirely through the enteric nervous system, without a pharyngeal swallowing sequence ✓
• B Origin in the swallowing centre of the medulla with sequential activation identical to primary peristalsis
• C Dependence on circulating motilin released during the fasted state
• D Requirement for conscious effort and voluntary cortical input to begin

Explanation

Secondary peristalsis is triggered by local distension of the oesophageal wall rather than by a swallow. The stimulus activates intrinsic sensory neurons of the myenteric plexus, and the ascending excitatory and descending inhibitory circuits of the enteric nervous system generate the peristaltic wave, with vagal pathways modulating it. It occurs without pharyngeal activity and without conscious awareness, and it clears residual food and refluxed material that primary peristalsis left behind.

Reference: Guyton and Hall Textbook of Medical Physiology, 14th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.