Final answer:
The relaxation of the lower esophageal sphincter permits a bolus to pass from the esophagus into the stomach.
Step-by-step explanation:
The relaxation of the lower esophageal sphincter permits a bolus to pass from the esophagus into the stomach. Once in the esophagus, the food bolus is propelled through peristalsis, which involves the contraction and relaxation of muscles in the esophagus. When the bolus nears the stomach, distention of the esophagus initiates a short reflex relaxation of the lower esophageal sphincter, allowing the bolus to pass into the stomach. During this process, esophageal glands secrete mucus that lubricates the bolus and minimizes friction.