Digestive sac in the left upper abdominal cavity , which expands or contracts with the amount of food in it.
It has four regions: the cardia leads down from the esophagus ; the fundus curves above it; the body is the largest part; and the antrum narrows to join the duodenum at the pyloric valve. Iron and very fat-soluble substances (e.g., alcohol, some drugs) are absorbed in the stomach. enzymes and {{link=hydrochloric acid">hydrochloric acid from glands in its lining and moves the resulting chyme toward the small intestine . The vagus nerve and sympathetic nervous system control the stomach's secretions and movements. Emotional stress affects its function. Common disorders include gastritis , peptic ulcer , hiatal hernia , and cancer. See also digestion , gastrectomy .