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In anatomy, the stomach (in ancient Greek στόμαχος) is an organ in the gastrointestinal tract used to digest food. In general, the stomach's primary function is not the absorption of nutrients from digested food; this task is usually performed by the intestine. In most animals, the main job of the stomach is to break down large fat molecules into smaller ones, so that they can be absorbed into the intestines more easily. Latin names for the stomach include Ventriculus and Gaster; many medical terms related to the stomach start in "gastro-" or "gastric".
In humans, the stomach is a highly acidic environment - maintained at pH 1.5 - 2 by the secretion of hydrochloric acid(HCl) - with peptidase digestive enzymes, primarily pepsin. Pepsinogen is secreted by chief cells of the stomach and the acidic environment activates pepsinogen to form pepsin. In fact, the stomach's interior can secrete 2 to 3 litres of gastric fluid per day.
Contents
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- 1 Anatomy of the human stomach
- 2 Histology of the human stomach
- 3 Control of secretion and motility
- 4 Diseases
- 5 Ruminants
- 6 See also
- 7 References
- 8 External link
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Anatomy of the human stomach
The stomach lies between the esophagus and the first part of the small intestine (the duodenum). It is on the left side of the abdominal cavity, the fundus of the stomach lying against the diaphragm. Lying beneath the stomach is the pancreas, and the greater omentum hangs from the greater curvature.
It is divided into five sections, each of which has different cells and functions. The gastric juice, which is in the stomach, is highly acidic with a pH of 1-3. Gastric acid may cause or compound damage to the stomach wall or its layer of mucus, causing a peptic ulcer.
In humans, the stomach has a volume of about 50 ml when empty. When full, it can expand to hold about 1 liter of food.[1]
مقاله Stomach