Pylorus#Antrum

File:Illu stomach.jpg
2. Fundus
3. Anterior wall
4. Greater curvature
5. Lesser curvature
6. Cardia
9. Pyloric sphincter
10. Pyloric antrum
11. Pyloric canal
12. Angular incisure
13. Gastric canal
14. Rugal folds ]]

The pylorus is the furthest part of the stomach that connects to the duodenum. It is divided into two parts, the antrum, which connects to the body of the stomach, and the pyloric canal, which connects to the duodenum.{{cite book|last=Drake|first=Richard L.|title=Gray's anatomy for students|year=2005|publisher=Elsevier/Churchill Livingstone|location=Philadelphia|isbn=978-0-8089-2306-0|page=272|author2=Vogl, Wayne |author3=Tibbitts, Adam W.M. Mitchell |author4=illustrations by Richard |author5= Richardson, Paul }}

{{See also|Gastric antral vascular ectasia}}

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The antrum also called the gastric antrum or the pyloric antrum is the initial portion of the pyloric region. It is near the bottom of the stomach, proximal to the pyloric sphincter, which separates the stomach and the duodenum. It may temporarily become partially or completely shut off from the remainder of the stomach during digestion by peristaltic contraction of the prepyloric sphincter; it is demarcated, sometimes, from the pyloric canal by a slight groove.

The pyloric canal ({{langx|la|canalis pyloricus}}) is the opening between the stomach and the duodenum.[http://uimc.discoveryhospital.com/main.php?id=900 University of Illinois Medical Center:Health Library] {{webarchive|url=https://web.archive.org/web/20120426232513/http://uimc.discoveryhospital.com/main.php?id=900 |date=2012-04-26 }} The wall thickness of the pyloric canal is up to 3 millimeters (mm) in infants younger than 30 days,{{cite journal|last1=Rohrschneider|first1=WK|last2=Mittnacht|first2=H|last3=Darge|first3=K|last4=Tröger|first4=J|title=Pyloric muscle in asymptomatic infants: sonographic evaluation and discrimination from idiopathic hypertrophic pyloric stenosis.|journal=Pediatric Radiology|date=June 1998|volume=28|issue=6|pages=429–34|pmid=9634457|doi=10.1007/s002470050377}} and up to 8 mm in adults.{{cite journal|last1=Lin|first1=Hsien-Ping|last2=Lin|first2=Yu-Chiang|last3=Kuo|first3=Chen-Yun|title=Adult idiopathic hypertrophic pyloric stenosis|journal=Journal of the Formosan Medical Association|volume=114|issue=7|year=2015|pages=659–662|issn=0929-6646|doi=10.1016/j.jfma.2012.07.001|pmid=26154756|doi-access=free}}

The pyloric sphincter, surrounding the pyloric orifice is a strong ring of smooth muscle at the end of the pyloric canal which lets food pass from the stomach to the duodenum. It acts as a valve, controlling the outflow of gastric contents into the duodenum{{cite book|last1=Snell|first1=Richard S.|title=Clinical Anatomy by Regions|date=2008|publisher=Lippincott Williams & Wilkins|isbn=978-0781764049|page=220|url=https://books.google.com/books?id=7SZWRe2OBlgC&q=pyloric+sphincter}} and release of chyme. Its function is modulated by both the central and enteric nervous systems.{{cite book |author=Bruce M. Carlson |title=The Human Body: Linking Structure and Function |url=https://books.google.com/books/about/The_Human_Body.html?id=twUsDgAAQBAJ|publisher=Academic Press |year=2018 |isbn=9780128043325 |pages=331-355|quote=The pyloric sphincter controls emptying of the stomach. Its function is coordinated through actions of the central and enteric nervous systems. As acid stomach contents enter the duodenum, the alkaline secretion of Brunner’s glands in the duodenum protects the duodenal lining from ulceration.}} It receives sympathetic innervation from the celiac ganglion.

Image:Pyloric stomach LPO.JPG

Under microscopy, the pylorus contains numerous glands, including gastric pits, which constitute about half the depth of the pyloric mucosa. They consist of two or three short closed tubes opening into a common duct or mouth. These tubes are wavy, and are about one-half the length of the duct. The duct is lined by columnar cells, continuous with the epithelium lining the surface of the mucous membrane of the stomach, the tubes by shorter and more cubical cell which are finely granular. The glands contain mucous cells and G cells that secrete gastrin.Cardiac, fundus and pyloric regions of the stomach, Pyloric region. available from: http://histology.leeds.ac.uk/digestive/cardiac_pyloric.php (Last inspected April 16, 2017)

The pylorus also contains scattered parietal cells and neuroendocrine cells. These endocrine cells include D cells, which release somatostatin,{{cite book|last=Deakin|first=Barbara Young |display-authors=etal |title=Wheater's functional histology : a text and colour atlas|date=2006|publisher=Churchill Livingstone/Elsevier|isbn=978-0-443-068-508|page=273|edition=5th}} responsible for shutting off acid secretion. (There is a second hormone-sensitive population near the fundus.)

Unstriated muscles, which are entirely involuntary, are located at the pylorus.

The pylorus is one component of the gastrointestinal tract. Food from the stomach, as chyme, passes through the pylorus to the duodenum. The pylorus, through the pyloric sphincter, regulates entry of food from the stomach into the duodenum.

In such conditions as stomach cancer, tumours may partly block the pyloric canal. A special tube can be implanted surgically to connect the stomach to the duodenum so as to facilitate the passage of food from one to the other. The surgery to place this tube is called a gastroduodenostomy.

{{Main|Pyloric stenosis}}

Pyloric stenosis refers to a pylorus that is narrow. This is due to congenital hypertrophy of the pyloric sphincter. The lumen of the pylorus is narrower, and less food is able to pass through. This problem is often detected in the early weeks of life. When it is present, a newborn baby may projectile vomit after eating, but despite vomiting remain hungry. Pyloric stenosis may be managed by the insertion of a stent, or through surgical cutting of the pyloric sphincter, a pyloromyotomy.{{cite book|last=Clayden|first=Tom Lissauer, Graham|title=Illustrated textbook of paediatrics|date=2007|publisher=Mosby/Elsevier|location=Edinburgh; New York|isbn=9780723433972|pages=207–208|edition=3rd}}

• Pyloric tumors
• Pyloric gland adenoma{{cite journal|last1=Chen|first1=ZM|last2=Scudiere|first2=JR|last3=Abraham|first3=SC|last4=Montgomery|first4=E|title=Pyloric gland adenoma: an entity distinct from gastric foveolar type adenoma.|journal=Am J Surg Pathol|date=2009|volume=33|issue=2|pages=186–193|doi=10.1097/PAS.0b013e31817d7ff4|pmid=18830123}}

Image:Stomach2.gif|Stomach

File:Stomach dissection highlighting pyloric antrum.jpg|Dissection showing the stomach and pylorus in a cadaver. The antrum of the pylorus is shown in green.

{{Anatomy-terms}}

• A Confederacy of Dunces#Ignatius J. Reilly

{{Reflist}}

• "[https://web.archive.org/web/20081206092227/http://activate.lww.com/semdweb/internetsomd/ASP/1557908.asp Pylorus]", Stedman's Online Medical Dictionary at Lippincott Williams and Wilkins
• {{SUNYAnatomyLabs|37|06|01|05}} - "Abdominal Cavity: The Stomach"
• {{SUNYAnatomyLabs|38|07|01|02}} - "Stomach, Spleen and Liver: The Pylorus"
• {{SUNYAnatomyImage|8|1|50}}

{{Digestive tract}}

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Category:Digestive system

Category:Stomach