Many people often confuse the large intestine with the small intestine. However the large intestine is wider (about 3 inches) yet shorter than the small intestine (in humans about 4. 9 feet in length as compared with 22 – 25 feet for the small intestine) and has a smooth inner wall. (Britannica) The large intestine consists of the cecum, ascending, transverse, descending and sigmoid colon, rectum and anus. The longitudinal muscle of the muscularis externa is concentrated into 3 bands called teniae coli.
These 3 bands of muscle form pouches (haustra) because they are shorter than the rest of the colon. The epithelium of the mucosa is mostly goblet cells, and has a numerous amount of crypts, there are no villi. (Martini, Ph. D. ) The ileocecal valve (sphincter) prevents materials from moving back into the ileum. In the upper half of the large intestine, enzymes from the small intestine complete the digestive process and bacteria produces the B vitamins (B12, thiamin, and riboflavin) as well as vitamin K. Martini, PhD)
The large intestine’s primary function is to absorb water and electrolytes from digestive residues and storage of fecal matter until it can be expelled. The large intestine is the last attraction in digestive tube and the location of the terminal phases of digestion. In comparison to other regions of the tube, there are huge differences among species in the relative size and complexity of the large intestine. Nonetheless, in all species it functions in three processes: (Marieb) *Recovery of water and electrolytes *Formation and storage of feces Microbial fermentation
A wide variety of diseases and disorders occur in the large intestine. The most frequent and common disease of the large intestine is Crohn’s disease. The cause of Crohn’s disease is unknown. ( Britannica) Apart from the greater tendency for fistulas to form and for the wall of the intestine to thicken until the channel is obstructed, it is distinguishable from ulcerative colitis by microscopic findings. In Crohn’s disease, the maximum damage occurs beneath the mucosa, and lymphoid conglomerations, known as granulomata, are formed in the submucosa.
Crohn’s disease attacks the perianal tissues more often than does ulcerative colitis. Although these two diseases are not common, they are disabling. ( Britannica) Because there is no specific etiology, a combination of anti-inflammatory drugs, including corticosteroids and aminosalicylic acid compounds, is used to treat Crohn’s disease. (Web MD) The drugs are effective both in treating acute episodes and in suppressing the disease over the long term. Depending on the circumstances, hematinics, vitamins, high-protein diets, and blood transfusions are also used.
Surgical resection of the portion of the large bowel affected is often done. The entire colon may have to be removed and the small intestine brought out to the skin as an ileostomy an opening to serve as a substitute for the anus. In ulcerative colitis, as opposed to Crohn’s disease, the rectal muscle may be preserved and the ileum brought through it and joined to the anus. (Web MD) Lactose intolerance is the inability to digest significant amounts of lactose, the major sugar found in milk.
Lactose intolerance is caused by a shortage of the enzyme lactase, which is produced by the cells that line the small intestine. Lactase breaks down milk sugar into two simpler forms of sugar called glucose and galactose, which are then absorbed into the bloodstream. Lactose intolerance is a problem caused by the digestive system. (lactose) People who do not have enough lactase to digest the amount of lactose they consume may feel very uncomfortable when they digest milk products.