Merck Manual

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Overview of the Esophagus

By

Kristle Lee Lynch

, MD, Perelman School of Medicine at The University of Pennsylvania

Reviewed/Revised Feb 2024
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The esophagus Throat and Esophagus The throat (pharynx) lies behind and below the mouth. When food and fluids leave the mouth, they pass through the throat. Swallowing of food and fluids begins voluntarily and continues automatically... read more is the hollow tube that leads from the throat (pharynx) to the stomach. Food does not just fall through the esophagus into the stomach. The walls of the esophagus propel food to the stomach by rhythmic waves of muscular contractions called peristalsis.

How the Esophagus Works

As a person swallows, food moves from the mouth to the throat, also called the pharynx (1). The upper esophageal sphincter opens (2) so that food can enter the esophagus, where waves of muscular contractions, called peristalsis, propel the food downward (3). The food then passes through the diaphragm (4) and lower esophageal sphincter (5) and moves into the stomach.

How the Esophagus Works

Just below the junction of the throat and the esophagus is a band of muscle called the upper esophageal sphincter. Slightly above the junction of the esophagus and the stomach is another band of muscle called the lower esophageal sphincter. When the esophagus is not in use, these sphincters close so that food and stomach acid do not flow back up the esophagus from the stomach to the mouth. During swallowing, the sphincters open so food can pass to the stomach.

With aging, the strength of esophageal contractions and the pressure in the sphincters decrease. This condition makes older adults more prone to backflow of acid from the stomach (gastroesophageal reflux or GERD Gastroesophageal Reflux Disease (GERD) In gastroesophageal reflux disease, stomach contents, including acid and bile, flow backward from the stomach into the esophagus, causing inflammation in the esophagus and pain in the bottom... read more Gastroesophageal Reflux Disease (GERD) ), especially when lying down after eating.

How the Esophagus Works
VIDEO

Esophageal and swallowing disorders include the following:

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