Stomach

The stomach is a hollow, muscular organ in the upper abdomen, part of the alimentary canal, responsible for initiating the digestion of food. It is situated below the diaphragm and connects the esophagus to the small intestine. Anatomically, the stomach is divided into several regions: the cardia, where contents from the esophagus enter; the fundus, which stores undigested food and gases released during chemical digestion; the body, the main region where digestion occurs; and the pylorus, controlling food passage to the small intestine. The inner lining, or mucosa, contains glands that produce stomach acid and enzymes, creating a highly acidic environment for breakdown of food.

Functionally, the stomach serves to temporarily store ingested food, mechanically grind it down, and chemically digest it, especially proteins, through the action of enzymes and gastric acid. This acidic mixture, known as chyme, is gradually released into the duodenum where further digestion and absorption occur. The stomach's role is regulated by a complex interaction of neural and hormonal signals, ensuring coordinated contractions (known as peristalsis) and controlled release of digestive secretions. Issues with stomach function can lead to various disorders, such as gastritis, ulcers, and cancer, impacting overall health and requiring medical intervention.