Digestive System

The digestive system is a group of organs joined in a long, twisting tube from the mouth to the anus. It is also called the alimentary canal and the gastrointestinal tract. The major parts of that tube are:

• mouth
• esophagus
• stomach
• small intestine
  • duodenum
  • jejunum
  • ileum
• large intestine (also called the colon)
  • cecum
  • ascending colon
  • transverse colon
  • descending colon
  • sigmoid colon
  • rectum

Inside this tube is a lining called the mucosa. The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) says that in the mouth, stomach and small intestine, the mucosa contains tiny glands that produce juices to help digest our food. Other organs that aren't part of the tube - the liver, gallbladder and the pancreas - produce and store digestive juices that are used in the intestine. In addition, parts of other organ systems (for instance, nerves and blood) play a role in the digestive system.

The large, hollow organs of the digestive system contain muscle that enables their walls to move. The movement of organ walls can propel food and liquid and also can mix the contents within each organ. Typical movement of the esophagus, stomach and intestine is called peristalsis.

After we swallow, food enters the esophagus. At the end of the esophagus, a ring-like valve opens, to let food enter the stomach. The stomach stores the food and liquid, mixes it with digestive juices, and then empties its contents slowly into the small intestine. Food is further digested in the small intestine, where nutrients from the food are absorbed through the intestinal walls. Digestion continues in the large intestine or colon. The waste products of this process then remain in the colon, usually for a day or two, until the feces are expelled by a bowel movement.

The American College of Gastroenterology (ACG) says more than 95 million people in the United States have a digestive problem and over 10 million end up in the hospital each year. Digestive diseases range from the occasional upset stomach (Read about "Indigestion") to the more life-threatening colon cancer (Read about "Colorectal Cancer") and encompass disorders of the gastrointestinal tract, the liver, the gallbladder and the pancreas.

The following links will provide you with information on a number of diseases and conditions that can affect the digestive system.