thumb|right|A simplified image showing peristalsis In the esophagus, two types of peristalsis occur: First, there is a primary peristaltic wave, which occurs when the bolus enters the esophagus during swallowing. The primary peristaltic wave forces the bolus down the esophagus and into the stomach in a wave lasting about 8–9 seconds. The wave travels down to the stomach even if the bolus of food descends at a greater rate than the wave itself, and continues even if for some reason the bolus gets stuck further up the esophagus. If the bolus gets stuck or moves slower than the primary peristaltic wave (as can happen when it is poorly lubricated), then stretch receptors in the esophageal lining are stimulated and a local reflex response causes a secondary peristaltic wave around the bolus, forcing it further down the esophagus, and these secondary waves continue indefinitely until the bolus enters the stomach. The process of peristalsis is controlled by the medulla oblongata. Esophageal peristalsis is typically assessed by performing an esophageal motility study. A third type of peristalsis, tertiary peristalsis, is dysfunctional and involves irregular, diffuse, simultaneous contractions. These contractions are suspect in esophageal dysmotility and present on a barium swallow as a "corkscrew esophagus".
thumb|right|A simplified image showing peristalsis In the esophagus two types of peristalsis occur First there is a primary peristaltic wave which occurs when the bolus enters the esophagus during swallowing The primary peristaltic wave forces the bolus down the esophagus and into the stomach in a wave lasting about 8–9 seconds The wave travels down to the stomach even if the bolus of food descends at a greater rate than the wave itself and continues even if for some reason the bolus gets stuck further up the esophagus If the bolus gets stuck or moves slower than the primary peristaltic wave (as can happen when it is poorly lubricated) then stretch receptors in the esophageal lining are stimulated and a local reflex response causes a secondary peristaltic wave around the bolus forcing it further down the esophagus and these secondary waves continue indefinitely until the bolus enters the stomach The process of peristalsis is controlled by the medulla oblongata Esophageal peristalsis is typically assessed by performing an esophageal motility study A third type of peristalsis tertiary peristalsis is dysfunctional and involves irregular diffuse simultaneous contractions These contractions are suspect in esophageal dysmotility and present on a barium swallow as a "corkscrew esophagus"