Figure 18 - Effect of esophago-UES contractile reflex on the UES closure muscles.

Distention of the esophagus of a chronically instrumented awake dog with a balloon caused an increase in EMG activity of the TP, CP, and cervical esophagus, but primarily the CP. The response magnitude was related to the magnitude of the stimulus, and the response was greater closer to the UES. TP, thyropharyngeus; CP, cricopharyngeus; ESO, esophagus 1 cm below CP; ball-press, balloon pressure; LES, lower esophageal sphincter.