The stomach stores swallowed and digested food, mixes it with digestive juices, and empties its contents into the small intestine. The stomach is part of the body's gastrointestinal tract, according to the National Institute of Diabetes and Digestive and Kidney Diseases.
The body's GI tract begins at the mouth, includes the esophagus, stomach, small intestine, large intestine and rectum, and ends at the anus. After food has been chewed and broken down by saliva, the act of swallowing pushes the food down the esophagus. The esophagus empties into the stomach.
The stomach contains gastric juices made up of hydrochloric acid and pepsin. The juices in the stomach work to break down protein and kill harmful bacteria, reports Live Science. Hydrochloric acid in the stomach kills bacteria by sterilizing it and helps to absorb minerals like magnesium, sodium and iron. Hydrochloric acid is very corrosive and has the ability to digest the stomach were it not protected by a mucus lining.
When hydrochloric acid is not functioning properly, it interferes with the stomach's ability to kill germs. Digestive infections, such as ones from bacteria like H. pylori, cause some types of ulcers. Hypochlorhydria occurs when the stomach produces too little acid and leads to malabsorption of vitamins, nutrients and minerals, says SF Gate.