The pharyngoesophageal sphincter is normally closed to prevent oesophageal secretions from entering the pharynx during breathing.

Question

Quizplus · Accepted Answer

The pharyngoesophageal sphincter, also known as the upper esophageal sphincter, is normally closed to prevent air from entering the esophagus during breathing and to prevent the reflux of gastric contents into the esophagus. It does not function to prevent esophageal secretions from entering the pharynx.

The Pharyngoesophageal Sphincter Is Normally Closed to Prevent Oesophageal Secretions