The colon (fachsprachlich eingedeutscht the colon, from the Greek κόλον (colon) " gut ", " sausage ", Latinized the colon ) is the middle section of the large intestine of mammals. It starts after the cecum ( cecum ), and merges at its end into the rectum ( rectal ) on. The German term colon is rarely used both in science and in everyday language.
The human colon:
Human colon extends approximately in the form of an inverted U. There are four sections:
- Ascending colon: ascending colon
- Transverse colon: transverse colon ( transverse colon ), to the right colic flexure ( flexure coli dextra )
- Descending colon: descending colon, according to the left colic flexure ( left colic flexure )
- Sigmoid colon: Sigma- loop, Sigma, sigmoid
In humans, the ascending colon is retroperitoneal (more precisely, secondarily retroperitoneal ). The part of the peritoneum that connects the ascending colon to the posterior abdominal wall fascia is called by Toldt. The transverse colon is intraperitoneally, making it much more flexible, because it is not fixed by the peritoneal sheath of the abdominal wall to the same extent. It can be found here only points of attachment on the Radix mesocolontransversum (via a peritoneal fold that includes the transverse colon, stomach, and upper part of the duodenum ), as well as the ligamentum gastrocolicum (connection of stomach and transverse colon ). The descending colon is like its counterpart ( secondary) retroperitoneal.
- Haustra: externally visible bulges of the colon wall
- Plicae semilunares coli: inner visible wrinkles, the externally define as the constrictions haustra each other
- Taeniae: three outer longitudinal muscle strips ( taenia libera, tenia mesocolica, Taenia omental )
- Appendices epiploic: stuffed with fat bulges of the outer layer, tunica serosa
The arterial blood supply of the ascending colon via the middle colic artery artery. The transverse colon is supplied by middle colic artery and the descending colon media of the artery middle colic artery. The first two arteries are branches of the superior mesenteric artery during the middle colic artery, a branch of the artery is inferior mesenteric artery. The coverage area of both arteries connected by vascular arcades on the Riolan anastomosis. The venous outflow of blood via the mesenteric veins towards the portal vein ( portal vein ).
The autonomic innervation of the colon takes place on the part of the sympathetic nervous system via the sympathetic trunk (Latin sympathetic trunk ), the major and minor splanchnic nerve and prevertebral ganglia. The parasympathetic innervation of the vagus nerve splits with branches of the sacral pelvic splanchnic nerves. The blurred transition of these parasympathetic innervation is located approximately in the last third of the transverse colon at Cannon -Böhm point.
Normal appendix with Bauhinscher flap ( ascending colon )
Colon of predators
The colon has in predators, in contrast to that of humans and herbivores, no taeniae and a smooth surface. A sigmoid colon is by predators also not formed. The "U" is open to them, due to the different body orientation to the rear.
In the herbivores ( herbivores ) and also in some omnivores ( omnivores ) of the colon is sometimes considerably modified as it still serves the microbial digestion of cellulose to a significant extent. These structural variations relate primarily to the ascending colon.
In horses, the ascending colon is also known as " large colon ", as it is very spacious with approximately 3-4 m in length and about 100 l capacity. The large colon is superimposed in the form of two U-shaped loops ( also referred to as a double horseshoe-shaped ). The colon begins with a right ascending limb ( ventral colon dextrum ) proposes in the flexure sternal (breastbone curvature ) to the left and pulls as the left ventral longitudinal position ( ventral colon sinistrum ) back toward the pelvic inlet. In the Beckenflexur ( Flexura pelvina ) it is reflected to move up and pulls as the upper left longitudinal position ( dorsal colon sinistrum ) towards the diaphragm. There it bends to the right ( diaphragm curvature, flexure diaphragmatic ) and pulls as right upper longitudinal position ( dorsal colon dextrum ) back to back and then passes into the transverse colon and descending colon.
In the even-toed ungulates, lagomorphs and guinea pig ascending colon is rolled ( ansa spiralis coli). In cattle, this colon loops are placed into a flat spiral, the pig, the loops form a cone, similar to the shape of a beehive.
In some mammals (such as horses, pigs, rabbits, chinchillas ), the longitudinal muscle layer such as the colon in humans strips ( taenia ) is reinforced. This gives rise to characteristic outgrowths between these taenia, the Poschen (Latin haustra ).
- Colitis ( colon inflammation)
- Ulcerative colitis
- Colon cancer
- Crohn's disease
- Constipation ( constipation)
Abdominal pain was formerly known as " stomach ache ". In horses, the colon is often affected by displacements and blockages and thus seat of colic. Abnormal length of the colon is called Dolichokolie.