Pyloric tubes

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The pyloric tubes ( porter appendages, appendices pyloricae ) are a peculiarity of most bony fish . These are tubular protuberances of the pyloric part of the stomach , just before the confluence of the bile duct , which is why they often partially penetrate the liver . Their number ranges from 1 to over 1000. It has not yet been possible to demonstrate a physiological function. Since they show anatomically and histologically the same structure as the neighboring midgut , it is considered that they have the purpose of keeping certain bacteria in them in contact with chyme vitamins or the like. to be generated. Stomachless fish such as carp or butterfish do not have pyloric tubes. In the deep-sea fish Coccorella , the only appendix under the throat skin serves as a luminous organ in which luminous bacteria (see bioluminescence ) live. The pigmentation of the body cavity and the intestines in many fish species may serve to cover up any glow of the intestinal contents that could attract predators.

Number of pyloric tubes of some different species: pike, eel, catfish: 0; Flössler: 1 or 2; Perch, bullhead: 3; Zander: (6 or) 7; Herring: approx. 40. Trout: approx. 60, Huchen: 200, Ayu: up to 400; Cod and tuna: up to over 1000.

literature

  • W. Marinelli, A. Strenger: Comparative anatomy and morphology of vertebrates . Part 5. (in press) 2009.