language-icon Old Web
English
Sign In

Stomach

The stomach is a muscular, hollow organ in the gastrointestinal tract of humans and many other animals, including several invertebrates. The stomach has a dilated structure and functions as a vital digestive organ. In the digestive system the stomach is involved in the second phase of digestion, following chewing. It performs a chemical breakdown due to enzymes and hydrochloric acid.Greater omentum and stomach of humansA more realistic image, showing the celiac artery and its branches in humans; the liver has been raised, and the lesser omentum and anterior layer of the greater omentum removed.An autopsy of a human stomach, showing the many folds (rugae) of the stomach. 2012 Instituto Nacional de CardiologíaHuman stomachEndoscopic image of human fundic gland polyposis. The stomach is a muscular, hollow organ in the gastrointestinal tract of humans and many other animals, including several invertebrates. The stomach has a dilated structure and functions as a vital digestive organ. In the digestive system the stomach is involved in the second phase of digestion, following chewing. It performs a chemical breakdown due to enzymes and hydrochloric acid. In humans and many other animals, the stomach is located between the oesophagus and the small intestine. It secretes digestive enzymes and gastric acid to aid in food digestion. The pyloric sphincter controls the passage of partially digested food (chyme) from the stomach into the duodenum where peristalsis takes over to move this through the rest of the intestines. In humans, the stomach lies between the oesophagus and the duodenum (the first part of the small intestine). It is in the left upper part of the abdominal cavity. The top of the stomach lies against the diaphragm. Lying behind the stomach is the pancreas. A large double fold of visceral peritoneum called the greater omentum hangs down from the greater curvature of the stomach. Two sphincters keep the contents of the stomach contained; the lower oesophageal sphincter (found in the cardiac region), at the junction of the oesophagus and stomach, and the pyloric sphincter at the junction of the stomach with the duodenum. The stomach is surrounded by parasympathetic (stimulant) and sympathetic (inhibitor) plexuses (networks of blood vessels and nerves in the anterior gastric, posterior, superior and inferior, celiac and myenteric), which regulate both the secretory activity of the stomach and the motor (motion) activity of its muscles. In adult humans, the stomach has a relaxed, near empty volume of about 75 millilitres. Because it is a distensible organ, it normally expands to hold about one litre of food. The stomach of a newborn human baby will only be able to retain about 30 millilitres. The maximum stomach volume in adults is between 2 and 4 litres. In classical anatomy the human stomach is divided into four sections, beginning at the cardia, each of which has different cells and functions. The cardia is defined as the region following the 'z-line' of the gastroesophageal junction, the point at which the epithelium changes from stratified squamous to columnar. Near the cardia is the lower oesophageal sphincter. Recent research has shown that the cardia is not an anatomically distinct region of the stomach but region of the oesophageal lining damaged by reflux. The stomach bed refers to the structures upon which the stomach rests in mammals. These include the pancreas, spleen, left kidney, left suprarenal gland, transverse colon and its mesocolon, and the diaphragm. The term was introduced around 1896 by Philip Polson of the Catholic University School of Medicine, Dublin. However this was brought into disrepute by surgeon anatomist J Massey. The lesser curvature of the human stomach is supplied by the right gastric artery inferiorly and the left gastric artery superiorly, which also supplies the cardiac region. The greater curvature is supplied by the right gastroepiploic artery inferiorly and the left gastroepiploic artery superiorly. The fundus of the stomach, and also the upper portion of the greater curvature, is supplied by the short gastric artery, which arises from the splenic artery.

[ "Diabetes mellitus", "Gastroenterology", "Surgery", "Pathology", "Biochemistry", "Antacid Effects", "H. Pylori Infections", "Stomach aspiration", "Gastric adenoma", "Diffuse Type Carcinoma" ]
Parent Topic
Child Topic
    No Parent Topic