A small bolus of food remains stuck above the lower oesophageal sphincter after a swallow. Distension of the oesophagus by this residue triggers another peristaltic wave that clears it. This wave is characterised by:

• A It is an antiperistaltic wave directed toward the pharynx
• B It uses striated muscle throughout the oesophagus unlike the primary wave
• C It requires an intact swallowing centre in the medulla to be initiated
• D It is generated entirely within the oesophageal enteric nervous system and persists after bilateral cervical vagotomy ✓

Explanation

Secondary peristalsis is initiated by local distension of the oesophageal body and is coordinated entirely by the intrinsic enteric nervous system, so it survives vagotomy and does not involve the medullary swallowing centre. It travels through the same smooth muscle segments as the primary wave, not through striated muscle, and it moves caudally like a normal peristaltic wave. The medulla is required only for the primary wave triggered by the swallowing reflex.

Reference: Ganong Review of Medical Physiology, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.