1.food storage: when eating diastole, the food temporarily stay in the stomach for digestion;
2. Digestion and absorption: mechanical and chemical digestion of food through peristalsis of the stomach and secretion of gastric acid and pepsin;
3. Secretion function: gastric juice, gastrin, etc.;
4. Defense function: gastric mucosal barrier, gastric acid, secretory IgG, IgA, etc., can prevent the invasion of pathogenic microorganisms and foreign bodies.