How is the digestive system organized?

The digestive system is actually a long hollow system of tubes, in which food is processed and absorbed.

Each part of the digestive tract contains muscles that squeeze and push food downward -- a process called peristalsis. Some of these muscles, called sphincter muscles, control the passage of food from one section to the next. For example, the esophagus and stomach are separated by a sphincter muscle that allows food into the stomach after eating, and out of the stomach upon vomiting. Valves separate other parts of the digestive tract.

All sections of the digestive tract are lined with specialized mucosal tissue that allows each part to perform its specific function. Gastrointestinal health depends largely on the condition of these linings.