Lestomac

Lestomac, commonly written l’estomac in French, refers to the stomach, a sac-like organ of the digestive system. It acts as a reservoir for ingested food and initiates digestion through mechanical mixing and chemical secretions.

It sits in the upper abdomen between the esophagus and the small intestine. Its main regions are the cardia, fundus, body, and pylorus. The stomach has two curvatures, the greater and lesser, and is connected to surrounding organs by peritoneal folds. It receives blood from branches of the celiac trunk and is innervated by parasympathetic fibers from the vagus nerve and sympathetic fibers from regional nerves.

Histologically, the stomach is lined by a simple columnar epithelium with mucus-secreting cells. Gastric glands in the fundus and body contain parietal cells that secrete hydrochloric acid and intrinsic factor, chief cells that secrete pepsinogen, and enteroendocrine cells that release regulatory peptides. The mucosa forms folds called rugae that enable expansion.

Functionally, mechanical digestion forms chyme through peristaltic contractions. Chemical digestion relies on acidification by HCl, activation of pepsin from pepsinogen, and protective mucus. Intrinsic factor, produced by parietal cells, is essential for vitamin B12 absorption in the ileum.

The stomach can store about 1 to 1.5 liters and gradually releases chyme into the duodenum through the pyloric sphincter. Gastric emptying is influenced by meal composition, volume, and neural and hormonal signals.

Clinical relevance includes gastritis, peptic ulcers, Helicobacter pylori infection, gastroesophageal reflux disease (GERD), and stomach cancer. The stomach absorbs only limited amounts beyond water and some drugs; its protective mechanisms include mucus, bicarbonate, and prostaglandins.