Stomach

Gaster

A J-shaped muscular organ in the left upper quadrant of the abdomen. It has four regions: cardia, fundus, body, and pylorus. The greater and lesser curvatures define its borders. Three layers of smooth muscle (oblique, circular, longitudinal) enable powerful mixing movements.

Тип Organ
Система органов Digestive
Область тела Abdomen
Латинское название Gaster
FMA ID 7148

Функция

Serves as a reservoir for ingested food, mixing and partially digesting it with gastric juice containing hydrochloric acid and pepsin. Mechanical churning converts food into chyme. Produces intrinsic factor for vitamin B12 absorption.

Клиническое значение

Peptic ulcers result from mucosal erosion by acid and Helicobacter pylori. Gastric cancer is a major cause of cancer mortality. Gastroesophageal reflux disease (GERD) causes chronic heartburn. Gastrectomy is performed for cancer and severe ulcer disease.

Подструктуры

ruminant stomach Gland

Часто задаваемые вопросы

What are the main functions of the stomach?
The stomach serves as a muscular reservoir that stores ingested food and progressively releases it into the duodenum. Its thick muscular walls churn food through peristaltic contractions, mechanically breaking it into smaller particles. Gastric glands secrete hydrochloric acid (creating a pH of 1.5-3.5) and pepsinogen (activated to pepsin), which begin protein digestion. Parietal cells also produce intrinsic factor, essential for vitamin B12 absorption in the terminal ileum.
What is the role of Helicobacter pylori in peptic ulcer disease?
Helicobacter pylori is a gram-negative bacterium that colonizes the gastric mucosa and disrupts its protective mechanisms by producing urease (which neutralizes acid locally), protease, and cytotoxins. It weakens the mucus layer, damages epithelial cells, and triggers chronic inflammation, predisposing the mucosa to erosion by gastric acid. H. pylori infection is present in over 90% of duodenal ulcers and about 70% of gastric ulcers, and eradication with antibiotics substantially reduces ulcer recurrence.
What causes gastroesophageal reflux disease (GERD)?
GERD occurs when gastric contents reflux into the esophagus due to dysfunction of the lower esophageal sphincter (LES)—the muscular barrier between the stomach and esophagus. Risk factors include obesity (increased intra-abdominal pressure), hiatal hernia (which displaces the LES above the diaphragm), pregnancy, certain foods (fatty foods, caffeine, alcohol), and lying flat after meals. Chronic acid exposure causes heartburn, regurgitation, and can lead to Barrett's esophagus—a precancerous condition.
What is the significance of intrinsic factor produced by the stomach?
Intrinsic factor is a glycoprotein secreted by gastric parietal cells that is essential for the absorption of vitamin B12 (cobalamin). It binds to B12 in the stomach and protects it from digestion, then delivers it to specific receptors in the terminal ileum for absorption. Conditions that destroy gastric parietal cells—such as autoimmune gastritis (causing pernicious anemia) or total gastrectomy—eliminate intrinsic factor production and lead to vitamin B12 deficiency, causing megaloblastic anemia and neurological damage.
What are the main regions of the stomach and what are their functions?
The stomach is divided into four anatomical regions: the cardia (immediately below the gastroesophageal junction) transitions food from the esophagus; the fundus (upper dome) stores swallowed air and food; the body (largest region) contains most of the acid-secreting parietal cells and pepsinogen-secreting chief cells; and the pyloric antrum and canal control the rate of gastric emptying into the duodenum through the pyloric sphincter, which prevents duodenogastric reflux.

Связанные структуры

muscularis mucosa gut muscularis musculature of trunk muscle group of trunk cavity of pharynx cavitas pharyngealis oropharyngeal gland gland of oral part of pharynx oropharynx mesopharynx trunk somite palatoglossal arch anterior pillar of fauces muscular coat of digestive tract muscular layer of digestive tract

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This content is for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider for medical decisions.

Data sources: Terminologia Anatomica, Foundational Model of Anatomy, Wikidata.