Pylorus

Gray's Anatomy : Stomach with Pylorus (outline)

Gray's Anatomy : Stomach with Pylorus (lithograph)

The pylorus ( ancient Greek πυλωρός pylōrós , German , Porter ' ) or pylorus is the annularly arranged smooth muscle , which extends between the antrum of the stomach ( pyloric antrum ) and the duodenum ( the duodenum is located). The pylorus is closed at rest. Its job is to regulate the transport of the food pulp from the stomach to the intestine.

functionality

When the stomach is empty, the pylorus is relaxed. The regulation of the opening and closing of the pylorus is a complicated process and not all aspects are understood. Not every peristaltic wave in the stomach is followed by an opening of the pylorus. The caloric content of the food, osmotic pressure and pH value in the stomach and duodenum play a role in this. The gastric emptying is controlled by the enteric nervous system of the stomach wall, the vagus nerve and various hormones . Liquids and food particles smaller than 1 mm pass the pylorus quickly, while larger food components are retained and further reduced in size in the stomach.

When the pylorus is briefly opened, a small portion ( bolus ) of the stomach contents ( chyme ) reaches the duodenum. The pyloric reflex that triggers the opening is a viscero - visceral reflex , which closes the muscle in the duodenum in the case of alkaline chyme and opens it in the case of acidic or fatty chyme. Gastric motility causes the stomach to empty, while postprandial motility is aimed at retaining food between meals for continuous delivery. Gastric motility plays a key role in the ingestion- regulating sensations of satiety , hunger, and bloating .

Malfunctions

A narrowing with functional closure is known as a pyloric stenosis . The hypertrophic pyloric stenosis is mainly caused by nerves and occurs almost exclusively in children. The resulting hypertrophy of the circular muscles of the gastric outlet must be removed surgically. Occasionally, pyloric stenosis can also result from narrowing of the pyloric canal due to gastric cancer or scarring after gastric ulcer . In veterinary medicine, pylar stenosis occurs mainly in dogs. Congenital pyloric stenoses are particularly common in German boxers and Boston terriers , while acquired ones occur primarily in dwarf and brachycephalic breeds .

If the pylorus does not close or if the closing mechanisms are disabled by gastric surgery, alkaline contents of the duodenum enter the stomach (enterogastric reflux), which leads to reflux gastritis . Will have primary bile acids and lysolecithin trigger. Typical here are morning vomiting as well as a feeling of fullness, pain in the upper abdomen, belching and nausea, which increase when eating.

Individual evidence

↑ Actually 'guardian' of the πύλη pýlē 'door' to the duodenum (duodenum).
^ JL Sellink: Examination of the Small Intestine by Means of Duodenal Intubation . Springer Science & Business Media, 2012, ISBN 978-94-015-7185-2 , p. 15.
^ Hans R. Koelz, Peter Aeberhard: Gastroenterologische Pathophysiologie . Springer-Verlag, 2013, ISBN 978-3-642-71876-2 , pp. 91-92.
↑ Jürgen Barnert, Martin Wienbeck: Focus: Motility disorders in the digestive tract . In: Deutsches Ärzteblatt . tape 93 , no. 4 . Deutscher Ärzte-Verlag , January 26, 1996, p. A-176 / B-146 / C-142 .
↑ Pieter Janssen, et al .: Review article: the role of gastric motility in the control of food intake . In: Alimentary pharmacology & therapeutics . 33, No. 8, February 22, 2011, pp. 880-894. doi : 10.1111 / j.1365-2036.2011.04609.x .
↑ M. Metzelder and B. Ure: Hypertrophic pyloric stenosis . In: Dietrich von Schweinitz, Benno Ure (Hrsg.): Pediatric surgery: Visceral and general surgery of childhood . Springer Science & Business Media, 2009, ISBN 978-3-540-89031-7 , pp. 278 ff.
↑ Linus Geisler: Internal medicine: textbook for nursing professions . W. Kohlhammer Verlag, 2006, ISBN 978-3-17-018768-9 , p. 337.
^ Hans Georg Nobody, Susi Arnold-Gloor: Internship at the dog clinic. Georg Thieme Verlag, 2006 ISBN 978-3-8304-4141-0 , p. 699.
↑ Rudolf Klußmann: The gastrointestinal patient: and his pre- and post-operative situation . Springer-Verlag, 2013, ISBN 978-3-642-71701-7 , p. 29

[1] Actually 'guardian' of the πύλη pýlē 'door' to the duodenum (duodenum).

[2] JL Sellink: Examination of the Small Intestine by Means of Duodenal Intubation . Springer Science & Business Media, 2012, ISBN 978-94-015-7185-2 , p. 15.

[3] Hans R. Koelz, Peter Aeberhard: Gastroenterologische Pathophysiologie . Springer-Verlag, 2013, ISBN 978-3-642-71876-2 , pp. 91-92.

[aerzteblatt-191-4] Jürgen Barnert, Martin Wienbeck: Focus: Motility disorders in the digestive tract . In: Deutsches Ärzteblatt . tape 93 , no. 4 . Deutscher Ärzte-Verlag , January 26, 1996, p. A-176 / B-146 / C-142 .

[5] Pieter Janssen, et al .: Review article: the role of gastric motility in the control of food intake . In: Alimentary pharmacology & therapeutics . 33, No. 8, February 22, 2011, pp. 880-894. doi : 10.1111 / j.1365-2036.2011.04609.x .

[6] M. Metzelder and B. Ure: Hypertrophic pyloric stenosis . In: Dietrich von Schweinitz, Benno Ure (Hrsg.): Pediatric surgery: Visceral and general surgery of childhood . Springer Science & Business Media, 2009, ISBN 978-3-540-89031-7 , pp. 278 ff.

[7] Linus Geisler: Internal medicine: textbook for nursing professions . W. Kohlhammer Verlag, 2006, ISBN 978-3-17-018768-9 , p. 337.

[8] Hans Georg Nobody, Susi Arnold-Gloor: Internship at the dog clinic. Georg Thieme Verlag, 2006 ISBN 978-3-8304-4141-0 , p. 699.

[9] Rudolf Klußmann: The gastrointestinal patient: and his pre- and post-operative situation . Springer-Verlag, 2013, ISBN 978-3-642-71701-7 , p. 29