The esophagus, also known as the food pipe, carries food from the mouth to the stomach. It is part of the digestive system and is approximately 10.5 inches long in fully grown adults.
There are three sections of the esophagus. These are the upper, middle and lower sections. There are four layers to the esophagus wall: the inner layer, or mucosa; the submucosa, or supportive tissue layer; the muscle layer, or muscularis; and the adventitia, or outer layer. The submucosa contains blood vessels and glands, while the outer layer provides a protective covering for the esophagus. The esophagus uses the mucosa and muscularis layers to carry food and liquid to the stomach. The muscle layer creates waves of muscles that push food down, while the mucus created by the skin-like inner layer helps the food to go down more easily and protects the esophagus from damage.
In the chest, the esophagus lays between the spine and the windpipe. Where the esophagus attaches to the top of the stomach is known as the gastroesophageal junction. In this junction there is a valve called the cardiac sphincter that helps to prevent food from moving back up the esophagus during the digestive process.