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Overview of the Digestive System

By

Atenodoro R. Ruiz, Jr.

, MD, The Medical City, Pasig City, Philippines

Last full review/revision Oct 2019| Content last modified Oct 2019
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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

The digestive system also includes organs that lie outside the digestive tract:

The digestive system is sometimes called the gastrointestinal system, but neither name fully describes the system’s functions or components. The organs of the digestive system also produce blood clotting factors and hormones unrelated to digestion, help remove toxic substances from the blood, and chemically alter (metabolize) drugs.

The abdominal cavity is the space that holds the digestive organs. It is bordered by the abdominal wall (composed of layers of skin, fat, muscle, and connective tissue) in front, the spinal column in back, the diaphragm above, and the pelvic organs below. It is lined, as is the outer surface of the digestive organs, by a membrane called the peritoneum.

Experts have recognized a powerful connection between the digestive system and the brain. For example, psychologic factors greatly influence contractions of the intestine, secretion of digestive enzymes, and other functions of the digestive system. Even susceptibility to infection, which leads to various digestive system disorders, is strongly influenced by the brain. In turn, the digestive system influences the brain. For example, long-standing or recurring diseases such as irritable bowel syndrome Irritable Bowel Syndrome (IBS) Irritable bowel syndrome is a disorder of the digestive tract that causes recurring abdominal pain and constipation or diarrhea. Symptoms vary but often include lower abdominal pain, bloating... read more , ulcerative colitis Ulcerative Colitis Ulcerative colitis is a chronic inflammatory bowel disease in which the large intestine (colon) becomes inflamed and ulcerated (pitted or eroded), leading to flare-ups (bouts or attacks) of... read more , and other painful diseases affect emotions, behaviors, and daily functioning. This two-way association has been called the brain-gut axis.

The Digestive System

The Digestive System
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Test your knowledge

Eosinophilic Esophagitis
Eosinophilic esophagitis is an inflammatory disorder in which the wall of the esophagus, the tube leading from the throat to the stomach, becomes filled with a type of white blood cells called eosinophils. Which of the following is believed to be the cause of this disorder?
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