Large Intestine
Large Intestine The large intestine is the terminal part of the gastrointestinal tract. The primary digestive function of this organ is to finish absorption, produce some vitamins, form feces, resorb water and eliminate feces from the body. The large intestine runs from the cecum, where it attches to the ileum, to the anus. It borders the small intestine on three sides. Despite its being around half as long as the small intestine – 4.9 feet versus 10 feet (1.5 – 3 meters) – it is called the large intestine because it is more than twice the diameter of the small intestine, 2.5 inches versus one inch (6 cm versus 2.5 cm). The large intestine is tethered to the posterior abdominal wall by the mesocolon, a double layer of peritoneal membrane. The large intestine is subdivided into four main regions: the cecum, the colon, the rectum, and the anus. The ileocecal valve, located at the opening between the ileum in the small intestine and the large intestine, controls the flow of chyme from the small to the large intestine. Large Intestine Anatomical Structures Like the small intestine, the mucosa of the large intestine has intestinal glands that contain both absorptive and goblet cells. However, there are several notable differences between the walls of the large and small intestines. For example, other than the anal canal, the mucosa of the colon is simple columnar epithelium. In addition, the wall of the large intestine has no circular folds, no villi, and essentially no enzyme- secreting cells. This is because most nutrients are already absorbed before chyme enters the large intestine.
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