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intestine(in-tes'tin) [L. intestinum]
The first part of the large intestine is the cecum, a pouch on the right side into which the ileum empties. Attached to the cecum is the vermiform appendix, about 7.5 to 10.4 cm (3 to 4 in) long. The ascending colon extends from the cecum upward to the undersurface of the liver, where it turns left (hepatic flexure) and becomes the transverse colon, which continues toward the spleen and turns downward (splenic flexure) to become the descending colon. At the level of the pelvic brim, the descending colon turns inward in the shape of the letter S and is then called the sigmoid colon. The rectum, about 10.2 to 12.7 cm (4 to 5 in) long, is the straight part that continues downward; the last 2.5 cm (1 in) is called the anal canal, which surrounds the anus.
The wall of the small intestine has circular folds (plicae circulares), which are folds of the mucosa and submucosa that look like accordion pleats. The mucosa is further folded into villi, which look like small (0.5 to 1.5 mm long) projections. The free surfaces of the epithelial cells have microscopic folds called microvilli that are collectively called the brush border. All of the folds increase the surface area for absorption of the end products of digestion. Intestinal glands (of Lieberkühn) between the bases of the villi secrete enzymes. The duodenum has submucosal Brunner's glands that secrete mucus. Enzymes secreted by the small intestine are peptidases, which complete protein digestion, and sucrase, maltase, and lactase, which digest disaccharides to monosaccharides. Some of these enzymes function in the brush border rather than in the lumen of the intestine. Hormones secreted by the duodenum are gastric inhibitory peptide, secretin, and cholecystokinin; these influence secretions or motility of other parts of the digestive tract.
The end products of digestion (amino acids, monosaccharides, fatty acids, glycerol, vitamins, minerals, and water) are absorbed into the capillaries or lacteals within the villi. Blood from the small intestine passes through the liver by way of the portal vein before returning to the heart.
intestineThe part of the digestive system lying between the outlet of the stomach (the PYLORUS) and the ANUS. It consists, sequentially, of the DUODENUM, the JEJUNUM, the ILEUM, the wide, pouch-like caecum, that carries the APPENDIX, the large intestine, or COLON, the S-shaped SIGMOID colon, the RECTUM and anus.
intestinethe part of the alimentary canal that lies between the stomach and the anus. Usually it is coiled and the internal surface is greatly increased by the presence of folds and projections (VILLI) to allow efficient digestion and absorption. Anteriorly, the intestine is lined with an EPITHELIUM containing ENZYME and MUCUS-secreting glands, and in higher vertebrates it is referred to as the SMALL INTESTINE. The posterior, large intestine, dehydrates the faeces which are stored here until voided in DEFECATION.
Patient discussion about intestine
Q. I recently had my surgery for bowel obstruction? I recently had my surgery for bowel obstruction? None of the diet was restricted for me by doctor but should I go for any special diet.
Q. Can Alcoholism makes you vulnerable to intestine infections? A friend of mine is a heavy drinker, he had something like 5 infections in the past year. Is it connected?
Q. What is the connection between bowel disease and arthritis? My son suffers from ulcerative colitis, and the doctor said that his recent joint pain can be as a result of the colitis. Why is that?