The digestive system, which extends from the mouth to the anus, is responsible for receiving food, breaking it down into nutrients (a process called digestion), absorbing the nutrients into the bloodstream, and eliminating the indigestible parts of food from the body. The digestive tract consists of the
Disorders that affect the digestive (gastrointestinal) system are called digestive disorders. Some disorders simultaneously affect several parts of the digestive system, whereas others affect only one part or organ.
Disorders that affect the digestive (gastrointestinal) system are called digestive disorders. Some disorders simultaneously affect several parts of the digestive system, whereas others affect only one part or organ. (See also Overview of the Digestive System.)
The esophagus is the hollow tube that leads from the throat (pharynx) to the stomach. Food does not just fall through the esophagus into the stomach. The walls of the esophagus propel food to the stomach by rhythmic waves of muscular contractions called peristalsis.
Gastroenteritis is inflammation of the lining of the stomach and small and large intestines. It is usually caused by infection with a microorganism but can also be caused by ingestion of chemical toxins, medications, or drugs.
Bleeding may occur anywhere along the digestive (gastrointestinal or GI) tract, from the mouth to the anus. Blood may be easily seen by the naked eye (overt), or blood may be present in amounts too small to be visible (occult). Occult bleeding is detected only by testing a stool specimen with special chemicals.
Anal cancer develops in the skin cells of the immediate area around the anus or in the lining of the transitional zone between the anus and the rectum (the anal canal). Unlike in the rectum and the large intestine, in which cancers are almost always adenocarcinomas, cancers of the anus are primarily squamous cell carcinomas.