What is the Esophagus?

Anatomy, Structure, and Function of the Esophagus

diagram showing the esophagus in anatomy
What is the esophagus and what is its structure and function?. A.D.A.M. Medical Encyclopedia

Definition: Esophagus

The esophagus is the hollow, muscular tube that carries food and liquids from the throat to the stomach. The esophagus runs through the middle of the chest cavity, an area known as the mediastinum.

Structure of the Esophagus

The esophagus begins at the throat (pharynx) and travels to the stomach, passing through the diaphragm en route. The length is usually around 25 cm (9 to 10 inches) in adults.

It passes behind the trachea (windpipe) and in front of the spine.

There are 2 sphincters (areas that can be opened and closed) in the esophagus.

  • The upper esophageal sphincter (UES) is under voluntary as well as involuntary control. It functions to prevent food and liquids from entering the windpipe (trachea,) in other words, prevents food from "going down the wrong way" (aspirating.) The IUS can be opened and closed consciously, as during burping, swallowing, and vomiting.
  • The lower esophageal sphincter (LES) is not under conscious control and works to prevent stomach acid from traveling into the esophagus. Alcohol, as well as several types of prescription medications, can cause relaxation of the LES leading to reflux.

Function of the Esophagus

The esophagus serves to pass food and liquids from the mouth down to the stomach. This is accomplished by periodic contractions (peristalsis) instead of gravity.

With vomiting, these contractions are reversed, allowing stomach contents to be returned to the mouth to spit out.

Medical Conditions Which Involve the Esophagus

There are many medical conditions which can occur in the esophagus. Some of these include:

  • Gastroesophageal reflux (GERD)
  • Heartburn - Heartburn refers to the burning feeling many people have experienced in their chest and upper abdomen after a heavy meal. Chronic heartburn is not something to take lightly, as damage to the esophagus is a risk factor for one type of esophageal cancer.
  • Esophagitis (inflammation of the esophagus) - The esophagus can become inflamed as a result of acid regurgitation from the stomach, from infections, or from damage secondary to radiation therapy given to the chest.
  • Barrett's esophagus - Barrett's esophagus is a "precancerous" change in the tissue lining the esophagus, often caused by long-standing GERD. If you have had chronic GERD with symptoms of heartburn, your doctor may recommend a test to evaluate for Barrett's esophagus. If changes are noted, further treatment may be considered to reduce the risk of developing esophageal cancer in the future.
  • Esophageal cancer - Esophageal cancer is a cancer with a low survival rate. There are 2 major types of this cancer. One type, squamous cell esophageal cancer, is thought to be related to a history of heavy smoking and drinking. Another type, esophageal adenocarcinoma is often times found in people with longstanding heartburn.
  • Mallory-Weiss tears - These are deep tears of the esophagus which sometimes occur with violent vomiting.
  • Esophageal varices - These are essentially "varicose veins" involving the veins of the esophagus which become dilated most commonly with cirrhosis of the liver.
  • Achalasia - Achalasia is a condition in which the lower esophagus does not relax, preventing food from passing into the stomach.

Sources:

American Cancer Society. What is Cancer of the Esophagus? Updated 03/20/15. http://www.cancer.org/cancer/esophaguscancer/detailedguide/esophagus-cancer-what-is-cancer-of-the-esophagus

U.S. National Library of Medicine. MedlinePlus. Esophagus Disorders. Updated 08/12/16. https://medlineplus.gov/esophagusdisorders.html

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