Spleen – The spleen arises from the mesodermal dorsal mesentery (the foregut arises from the endoderm not mesoderm). But the spleen shares the same blood supply as many of the mature structures that arise from the foregut (i.e. the celiac artery)
Nerve supply
The enteric nervous system is one of the major divisions of the nervous system derived from neural crest cells. In mammals, it is composed of large number of interconnected ganglia that are arranged into two concentric rings embedded throughout the gut wall, beginning in the esophagus and ending in the anus. The main function of the ENS is to control the secretory activity of the gastrointestinal glands and peristalsis of the gastrointestinal wall.[1] A large number of organs derived from the developing foregut also receive input from the vagus nerve, which also works in tandem with the ENS to control gastrointestinal function.
Development
Further information:
greater curvature.[2] The expanding dorsal stomach wall then rotates the on its transverse plane, pulling its caudal portion upward and forcing the upper duodenum into a C shape. This rotation positions the left vagus nerve anteriorly and right vagus nerve posteriorly.[2]
While the hindgut and midgut are only attached dorsally to the body wall by a fold of
ventral mesogastrium
.
As the stomach rotates during early development, the dorsal and ventral mesentery rotate with it; this rotation produces a space anterior to the expanding stomach called the greater sac, and a space posterior to the stomach called the lesser sac. After this rotation the dorsal mesentery thins and forms the greater
celiac trunk, and venous drainage is by the portal venous system. Lymph from these organs is drained to the prevertebral celiac nodes at the origin of the celiac artery from the aorta
.
Signalling pathways
In vertebrates, functional differentiation continues even after birth, with the transformation into the adult phenotype occurring through
sox9.[3] Recent research has suggested that most foregut malformations are due to defects in these signalling pathways, with sonic hedgehog gene knockout mice showing phenotypes similar to those seen in patients with esophageal atresia/stenosis, tracheo-esophageal fistula, and respiratory tract anomalies.[4]
Clinical significance
congenital defect of the digestive system in which the continuity of the esophageal wall is interrupted. In most cases, the upper esophagus fails to connect with the lower esophagus and stomach.[5]
Esophageal stricture is the narrowing of the esophagus resulting in swallowing difficulties.[5]
pyloric sphincter, obstructing the passage of food.[5]
Biliary atresia is a congenital defect where the common bile duct, which connects the small intestine to the liver, is obstructed or absent.[5]
Pancreatic divisum, where the pancreatic duct fails to form, and Annular pancreas, where extra pancreatic tissue grows and wraps around the duodenum leading to obstruction by constriction.[5]
References
^ abSanderson, I. Walker, W.A., (1998) Development of the Gastrointestinal Tract. B.C. Decker Inc, Lewiston, NY
^Faure, S. De Santa Barbara, P. (2011) Molecular Embryology of the Foregut, Faure S, De Santa Barbara P. Molecular embryology of the foregut. Journal of Pediatric Gastroenterology and Nutrition. 52.Suppl 1: S2–3. PMC. Web. 3 Mar. 2015.
^Litingtung, Y. Lei, L. Westphal, H. Chiang, C. (1998) Sonic Hedgehog is Essential to Foregut Development. Nature Genetics 20, 58–61 doi:10.1038/1717
^ abcdePansky, B. (1982). Chapter 87: Congenital Malformations of the Digestive System: Foregut Malformations. In Review of medical embryology. New York: Macmillan.
