The thick, cylindrical and grooved part of the small intestine extending from the ileum to the anus is called the large intestine. The function of the human colon is described.
1. Absorption and Reabsorption: Water, mineral salts, sodium, chloride etc. are absorbed by the colon. 70-80% of the water present in the digestive waste is reabsorbed by the colon.
2. Reservoir of microorganisms: The appendix of the colon is said to be a protected reservoir of beneficial microorganisms. 500 species of bacteria live in the human colon. Bacteria in the appendix reestablish the intestinal bacterial flora when beneficial gut bacteria are destroyed. These bacteria break down non-nutritive food ingredients to produce short-chain fatty acids.
3. Fermentation and Digestion: There are 500 species of mitotic bacteria in the large intestine. These bacteria break down raw food ingredients in a fermentation process to produce short-chain fatty acids and release carbon dioxide, hydrogen and methane gases. Small fatty acids (acetic acid, propionic acid and butyric acid) provide energy to the cells of the colon wall.
4. Faecal production: Liquid chyme or mucus from the small intestine enters the large intestine and is absorbed into moist and soft stools. Usually 135 grams of feces are produced from 350 grams of feces.
