The oesophagus

Abstract

The oesophagus is a long narrow muscular tube which in man is approximately 25 cm long. It connects the pharynx with the stomach providing a conduit for bidirectional flow. Ingested material is actively propelled into the stomach by means of peristaltic contractions that are initiated by swallowing or when a bolus of food becomes lodged in the oesophagus. However, during vomiting the reverse occurs, but under these circumstances the force propelling gastric contents into the mouth is not derived from oesophageal peristalsis but from contractions of the abdominal muscles and diaphragm. At rest the oesophagus is closed by sphincters at both ends. The upper oesophageal sphincter is constricted so that air is prevented from entering the oseophagus during inspiration while tone in the lower oesophageal sphincter minimizes the reflux of acidic gastric contents.