Overview Esophageal motility overlaps with esophageal phase of swallowing swallowing is under involuntary ("reflex") control in the esophagus propels food bolus from the esophagus to the stomach food bolus is propelled from the pharynx, through the upper esophageal sphincter, and into the esophagus once the food bolus enters the esophagus, the upper esophageal sphincter contracts and closes to prevent the food bolus from refluxing into the pharynx a primary peristaltic wave of contraction mediated by the swallowing reflex involving a series of coordinated, sequential contractions propels the food bolus through the esophagus if the primary peristaltic wave of contraction does not clear the esophagus of food, a secondary peristaltic wave mediated by the enteric nervous system is initiated lower esophageal (cardiac) sphincter relaxes and opens as the lower esophageal (cardiac) sphincter relaxes and opens, the orad region of the stomach relaxes in a process called "receptive relaxation" receptive relaxation decreases pressure in the orad stomach and facilitates movement of the food bolus from the esophagus, through the lower esophageal (cardiac) sphincter, and into the stomach once the food bolus enders the orad stomach, the lower esophageal (cardiac) sphincter contracts and closes to prevent the food bolus from refluxing into the esophagus