A monogastric organism has only one stomach, and is the alternate gastric complex to a four-chambered stomach known as a ruminant. Examples of monogastric animals include rabbits, humans, and pigs.

The monogastric system

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Starting with the mouth where food enters and is first broken down by mastication, moistening and lubrication of food prior to swallowing by saliva. As food is swallowed, it slides down the esophagus into the stomach. As the stomach contracts, the cardiac sphincter prevents backflow while secretion of HCl and other enzymes is mixed with food. In the small intestine, nutrients are absorbed and duodenal cells secrete hormones which stimulate release of bile and pancreatic enzymes. This is sent into the large intestine where water is absorbed. Finally in the anus and the rectum the feces are stored and eventually excreted.

Comparison of monogastric and ruminant systems

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In both systems, excess protein and amino acids are used as an energy source. Carnivorous, herbivorous, and omnivorous diets are common in monogastric animals, while ruminant animals are usually herbivorous.

Animal anatomy