Your digestive system is tasked with taking the food and beverages you consume and breaking them down into simple compounds that your body can use for energy and tissue repair. These compounds are absorbed in the intestines and then sent to other organs via the bloodstream. Your stomach is a vital part of the digestive process and is a key organ associated with the breakdown of food. The stomach uses certain secretions to ensure proper food digestion.
Stomach Acid
The stomach contains and produces a large amount of hydrochloric acid, or HCl. This acid is strong enough to dissolve metal and kills bacteria that enter the stomach. With a pH of around 2, HCl is also able to help denature proteins, which makes them more susceptible to attacks from the enzyme, pepsin. To protect itself from the harmful effects of HCl, your stomach also secretes mucus, which protects the stomach lining from the acid.
Gastrin
Gastrin is an important hormone that induces the release of other gastric juices, including stomach acid. Gastrin is secreted in response to food entering the stomach and mouth. As the concentration of stomach acid rises, gastrin levels begin to fall. Normal gastrin levels are usually less than 100 pg/mL. Elevated gastrin levels often lead to peptic ulcer disease.
Pepsin
Pepsin is a powerful enzyme secreted by the cells of the stomach. Pepsin aids in the digestion of all proteins and is most functional when in an acidic environment. A typical person secretes around 80 mg of pepsin with each meal, the University of Cincinnati reports. Pepsin begins breaking down complex proteins into smaller amino acids, which the body absorbs more easily. Taking antacids decreases the acidic environment in the stomach and, therefore, can also reduce the function of pepsin.
Mechanical Function of the Stomach
Aside from secreting acids and other enzymes, the stomach also performs a mechanical, or physical, function. It stores all the food and drinks you ingest. To accommodate large meals, the stomach can expand by relaxing its muscles. Furthermore, the stomach can contract its muscles, which allows for the mixing of ingested substances with the digestive juices found within the stomach. This mixing speeds up the digestive process. The stomach also helps conduct ingested food to the small intestine. The transfer of food from the stomach to the small intestine is a gradual process, so that the small intestine has time to further digest and absorb all the nutrients you consume.
References
- MedlinePlus; Gastrin; David C. Dugdale, III, MD; August 2009
- National Digestive Diseases Information Clearinghouse; Your Digestive System and How It Works; April 2008
- University of Cincinnati; Digestive System; J. Stein Carter; November 2004
