Table of Contents
The esophagus, commonly called the food pipe, is a narrow muscular tube about nine-and-a-half inches long. It begins below the tongue and ends at the stomach. The esophagus is narrowest at the top and bottom; it also narrows slightly in the middle.
The esophagus consists of three basic layers:
- An outer layer of fibrous tissue.
- A middle layer containing smoother muscle.
- An inner membrane, which contains many tiny glands.
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Click the icon to see an image of the esophagus. |
When a person swallows food, the esophagus moves it into the stomach through the action of wave-like muscle contractions, called peristalsis. In the stomach, acid and various enzymes break down the starch, fat, and protein in food. The lining of the stomach has a thin layer of mucus that protects it from these fluids.
If acid and enzymes back up into the esophagus, however, its lining offers only a weak defense against these substances. Instead, several other factors protect the esophagus. The most important structure protecting the esophagus may be the lower esophageal sphincter (LES). The LES is a band of muscle around the bottom of the esophagus, where it meets the stomach.
- After a person swallows, the LES opens to let food enter the stomach. It then closes immediately to prevent regurgitation of the stomach contents, including gastric acid.
- The LES maintains this pressure barrier until food is swallowed again.
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Click the icon to see an image of the stomach. |
If the pressure barrier is not enough to prevent regurgitation and acid backs up (reflux), peristaltic action of the esophagus serves as an additional defense mechanism, pushing the backed-up contents back down into the stomach.
Review Date: 07/11/2010
Reviewed By: Reviewed by: Harvey Simon, MD, Editor-in-Chief, Associate Professor
of Medicine, Harvard Medical School; Physician, Massachusetts
General Hospital. Also reviewed by David Zieve, MD, MHA, Medical
Director, A.D.A.M., Inc.
A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org)
