What occurs at the lower esophageal sphincter during swallowing?

During swallowing, the lower esophageal sphincter relaxes to allow the bolus to pass into the stomach. This physiological change is crucial for the swallowing process, as it ensures that the food moves smoothly from the esophagus into the stomach without obstruction. The relaxation of the sphincter is a coordinated response that occurs as part of the swallow reflex, which helps prevent aspiration and allows for effective gastric emptying.

This movement is particularly important because the lower esophageal sphincter serves as a barrier between the esophagus and the stomach, maintaining a one-way flow of food. When it relaxes during swallowing, it permits not only the bolus to enter the stomach but also allows for the proper functioning of the digestive process. After the passage of food, the lower esophageal sphincter will tighten again to prevent the backflow of stomach contents, which helps in maintaining proper gastrointestinal function.