The stomach is located in the upper-left area of the abdomen below the liver and next to the spleen.
Its expanded J shape and three layers of muscle help turn liquid and chewed food into material suitable for the intestinal tract.
When the stomach is empty, the inside has small folds called rugae. As the stomach expands, these folds disappear to accommodate the new contents.
The average stomach can hold about 1.5 gallons of food and liquid at maximum capacity. It only holds food for about four hours before passing it along the digestive tract.
The stomach’s main component for digestion is the powerful mix of secretions collectively called gastric juices. To counteract these strong juices, the stomach protects itself with mucus-like secretions. Without this protection, the stomach would essentially digest itself.
Cells in the stomach create the active ingredients in gastric juices:
Two muscular rings called sphincters also provide additional defense against the chemicals in the stomach by moving contents along. The esophageal sphincter separates the esophagus and the stomach. When that muscle doesn’t relax properly, it feels like it is difficult to swallow. On the opposite end of the stomach, the pyloric sphincter regulates the speed at which food moves down to the small intestine.
After the stomach has done its work, the highly acidic mixture of gastric juices and food (known as chyme) leaves the stomach, moves past the pyloric sphincter, and goes into the duodenum before entering the small intestine.
Because the chemicals in the stomach work due to a subtle balance, many problems can arise with the stomach. Some common conditions related to the stomach include: