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The foregut is the anterior part of the alimentary canal, from the mouth to the duodenum at the entrance of the bile duct, and is attached to the abdominal walls by mesentery. The foregut develops from the folding primitive gut, and is developmentally distinct from the midgut and hindgut. Although the term “foregut” is typically used in reference to the anterior section of the primitive gut, components of the adult gut can also be described with this designation. Pain in the epigastric region, just below the intersection of the ribs, typically refers to structures in the adult foregut.

Structures of the adult foregut

Esophagus (distal end)
Respiratory tract (lower respiratory tract)
Stomach
Duodenum (proximal half)
Liver
Gallbladder
Pancreas
Spleen - The spleen arises from the mesodermal dorsal mesentery but it is supplied by the foregut (i.e. the celiac artery)

Development of foregut

The foregut develops from a cranial region of endoderm created after the initial cephalocaudal folding of the embryo. Starting at the stomodeum, a rapid expansion of the primitive gut forms the esophagus, from which the respiratory bud branches off.^[1]During early foregut development, the esophagus lengthens considerably, reaching its proportional postnatal size. Simultaneously, the stomach begins to expand in width dorsally and ventrally in an asymmetric manner. This asymmetric expansion creates two curvatures, with the ventral side creating the lesser curvature and the dorsal side creating the greater curvature.^[1]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.^[1] While the hindgut and midgut are only attached dorsally to the body wall by a fold of peritoneum, the foregut also has a ventral attachment. Its two attachments are commonly referred to as the dorsal mesogastrium and the 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 omentum, which is attached to the greater curvature of the stomach. The ventral mesentery forms the lesser omentum, and is attached to the developing liver. In the adult, these connective structures of omentum and mesentery form the peritoneum, and act as an insulating and protective layer while also supplying organs with blood and lymph vessels as well as nerves.^[1] Arterial supply to all these structures is from the 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 foregut development

In vertebrates, functional differentiation continues even after birth, with the transformation into the adult phenotype occurring through epithelial-mesenchymal transition.^[2] Patterning events that determine tissue differentiation in vertebrates rely on several hox genes, the morphogen sonic hedgehog, and transcription factors such as sox2 and 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]

Foregut Malformations

Esophageal atresia is a 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 stenosis is the thickening (hypertrophy) of the muscle that forms the 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 disease exist as both congenital and acquired diseases. Two of the well known types of congenital defect are: 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]

Regulation of foregut

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.^[2] 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.

References

^ ^a ^b ^c ^d Sadler, T.W, (2011) Langman’s Medical Embryology (12th edition), LWW, Baltimore, MD
^ ^a ^b Sanderson, 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
^ ^a ^b ^c ^d ^e Pansky, B. (1982). Chapter 87: Congenital Malformations of the Digestive System: Foregut Malformations. In Review of medical embryology. New York: Macmillan.

External links

digest-008—Embryo Images at University of North Carolina
MedicalMnemonics.com: 2452
Foregut embryology at mcgill.ca
med.nyu.edu - embryology, Bogart, B
web.duke.edu - anatomy
www.indiana.edu - anatomy

UpToDate Contents

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English Journal

Identification and functional characterizations of a novel TRIF gene from grass carp (Ctenopharyngodon idella).

Yang C, Li Q, Su J, Chen X, Wang Y, Peng L.SourceCollege of Veterinary Medicine, Northwest A&F University, Yangling 712100, China.
Developmental and comparative immunology.Dev Comp Immunol.2013 Oct;41(2):222-9. doi: 10.1016/j.dci.2013.05.018. Epub 2013 May 31.
Toll/interleukin-1 receptor (TIR) domain containing adapter inducing interferon-β (TRIF) is an adapter in responding to activation of some toll-like receptors (TLRs), which provides early clearance of viral and bacterial pathogens. Here we identified and characterized a full-length genomic sequence
PMID 23732407

Bronchogenic/Foregut cyst of the ileal mesentery in a child mimicking ovarian mass.

Markel TA, Lin J, Fan R, Billmire DF.SourceDepartment of Pediatric Surgery, Indiana University School of Medicine and Riley Hospital for Children at Indiana University Health , Indianapolis, IN , USA.
Fetal and pediatric pathology.Fetal Pediatr Pathol.2013 Oct;32(5):357-61. doi: 10.3109/15513815.2013.768742. Epub 2013 Feb 25.
Intraabdominal bronchogenic cysts, a type of foregut cyst, are very rare. We report a case in a 12-year-old female who presented with severe abdominal pain and, in radiology workup, a cystic lesion that mimicked ovarian mass.
PMID 23438792

Multiple bursts of pancreatic ribonuclease gene duplication in insect-eating bats.

Xu H, Liu Y, Meng F, He B, Han N, Li G, Rossiter SJ, Zhang S.SourceInstitute of Molecular Ecology and Evolution, Institutes for Advanced Interdisciplinary Research, East China Normal University, Shanghai 200062, China.
Gene.Gene.2013 Sep 10;526(2):112-7. doi: 10.1016/j.gene.2013.04.035. Epub 2013 May 1.
Pancreatic ribonuclease gene (RNASE1) was previously shown to have undergone duplication and adaptive evolution related to digestive efficiency in several mammalian groups that have evolved foregut fermentation, including ruminants and some primates. RNASE1 gene duplications thought to be linked to
PMID 23644026

Japanese Journal

胸髄髄内発生と考えられた神経腸嚢胞の1例

西秀久,佐藤宰,佐野徳隆,黒山貴弘,奥圭佑,永田学,吉本修也,鳥橋孝一,黒崎義隆,小柳正臣,定政信猛,鳴海治,半田明,山形専
脳神経外科ジャーナル 21(8), 631-636, 2012-08-20
胸髄髄内発生と考えられた神経腸嚢胞の1手術例を報告する.症例は7歳の男児.比較的急速に進行する痙性対麻痺を呈した.脊髄MRIでTh1/2レベルの髄内に局在する嚢胞性病変を認めた.初回治療として嚢胞壁開窓術を行い,神経腸嚢胞の病理診断を得た.術後2週間で再発を認め,追加治療として嚢胞-くも膜下腔シャント術を施行したところ,嚢胞の消失と症状の改善が得られた.神経腸嚢胞は,脊索と前腸の不完全な分離により …
NAID 110009480324

Related Pictures

★リンクテーブル★

リンク元	「口咽頭膜」「下腸間膜動脈」「前腸」
拡張検索	「foregut endoderm」「congenital bronchopulmonary foregut malformation」

「口咽頭膜」

Foregut
	Diagram showing the expansion of amnion and delimitation of the umbilicus.
	Termination of the foregut.
Details
Carnegie stage	9
Precursor	Mesenchyme
Identifiers
Latin	Praeenteron, proenteron
TE	E5.4.4.0.0.0.2
FMA	45616
	Anatomical terminology [edit on Wikidata]

　　[★]

英: oropharyngeal membrane
同: 頬咽頭膜 buccopharyngeal membrane
ラ: membrana oropharyngealis
関: 原腸形成、排泄腔膜

図：L.96 図5-16C, L.97
初期咽頭胚において口窩(stomatodeum)と咽頭(pharynx)とを隔てる膜。
発生学的な由来は外胚葉と内胚葉。中胚葉は含まれない。
頭腸(＝前腸, foregut)の最前部腹側に位置する。
発生第3週以降。前腸が口咽頭膜（内胚葉由来）で閉じられているが、発生第4週以降に破れて羊膜腔と原始腸管との交通が確立する。

「下腸間膜動脈」

　　[★]

英: inferior mesenteric artery (Z), IMA
ラ: arteria mesenterica inferior
関: 上腸間膜動脈

L3

起始

腹大動脈

走行

分布

枝

腹腔動脈	foregut	前腸に由来する臓器(食道下部、胃、十二指腸、肝臓、胆嚢、膵臓)、脾臓 stomach to proximal duodenum; liver, gallbladder, pancreas
上腸間膜動脈	midgut	distal duodenum to proximal 2/3 of transverse colon
下腸間膜動脈	hindgut	distal 1/3 of transverse colon to upper portion of rectum

Henry Gray (1825-1861). Anatomy of the Human Body. 1918.

-IMA

「前腸」

　　[★]

英: foregut, pre-enteron
関: [[]]

腹腔動脈	foregut	前腸に由来する臓器(下気道(肺)、食道下部、胃、十二指腸、肝臓、胆嚢、膵臓)、脾臓 stomach to proximal duodenum; liver, gallbladder, pancreas
上腸間膜動脈	midgut	distal duodenum to proximal 2/3 of transverse colon
下腸間膜動脈	hindgut	distal 1/3 of transverse colon to upper portion of rectum

「foregut endoderm」

　　[★] 前腸内胚葉

関: anterior visceral endoderm

「congenital bronchopulmonary foregut malformation」

　　[★] 先天性気管支肺前腸奇形

[SADLER-1] Sadler, T.W, (2011) Langman’s Medical Embryology (12th edition), LWW, Baltimore, MD

[SANDERSON-2] Sanderson, I. Walker, W.A., (1998) Development of the Gastrointestinal Tract. B.C. Decker Inc, Lewiston, NY

[faure-3] 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-4] 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

[Pansky-5] Pansky, B. (1982). Chapter 87: Congenital Malformations of the Digestive System: Foregut Malformations. In Review of medical embryology. New York: Macmillan.

v t e Development of the digestive system

Foregut	Stomodeum Buccopharyngeal membrane Rathke's pouch Tracheoesophageal septum Pancreatic bud Hepatic diverticulum

Midgut	Midgut

Hindgut	Urorectal septum Proctodeum Cloaca Cloacal membrane

匿名

検索

案内

案内

foregut