Stomach : It is J shaped and present on the left side at anterior end of abdominal cavity posterior to diaphragm.

The stomach has four parts :

(1) Cardiac stomach : It is proximal part. The opening of oesophagus into cardiac stomach is guarded by cardiac sphincter which prevents the regurgitation of food. 

Section of the stomach

(2) Fundus : It extends above cardiac aperture and is filled with air. The part of cardiac stomach which extends towards anterior end above level of cardiac aperture is called fundus.

(4) Pyloric stomach : It is the distal narrowest part of stomach which opens into duodenum. Its opening is guarded by pyloric sphincter which permits the passage of fine-food particles into duodenum.

Functions :

1. Food is temporarily stored in stomach for about 4 - 5 hours.

2. The digestion occurs in the stomach and only proteins are digested.

3. Churning of food occurs in the stomach.