lower esophageal sphincter    • function in human digestive
system      TITLE: esophagus     TITLE: swallowing     ...within
the esophagus push the food downward. Folds in the esophageal
wall stretch out as materials pass by them and again contract
once they have passed. At the lower end of the esophagus, the
lower esophageal sphincter relaxes and food enters the stomach;
the sphincter then closes again to prevent reflux of gastric
juices and food materials.