Development of the Gut Tube and Esophageal Atresia

Folding of the embryo's body causes the endoderm-lined yolk sac cavity to form a tube known as the gut tube.

The gut is divided into three regions (foregut, midgut, and hindgut) based on its arterial supply.

The foregut, midgut, and hindgut are each associated with specific organs.

The foregut is supplied by branches of the celiac artery.

The midgut is supplied by branches of the superior mesenteric artery.

The hindgut is supplied by branches of the inferior mesenteric artery.

Mesoderm, a germ layer, contributes to the formation of the wall of the gut tube. This includes the muscular layers and connective tissue.

Neural crest cells, another type of germ layer, contribute to the formation of the nerves in the gut tube.

A condition where the upper esophagus ends in a closed tube, preventing food passage. Often associated with a connection between the trachea and esophagus (tracheoesophageal fistula) allowing stomach contents into the lungs.

A condition where the esophagus fails to reopen fully after being temporarily closed during development, narrowing the passage.

A condition where the stomach is pulled into the chest cavity due to a short esophagus, allowing other organs to enter the area.

The process where the esophagus grows longer during fetal development to keep pace with the overall growth of the embryo.

The rotation of the stomach during development, where the left side shifts forward and the right side shifts back.

The process of forming distinct regions of the gut tube by sequentially expressing HOX genes along the anterior-posterior axis of the developing embryo.

Different layers of the gut wall are formed by the concentration of Sonic Hedgehog (SHH) signaling protein from the endoderm.

The gut tube temporarily closes during week 5 due to rapid endodermal growth.

The gut tube reopens in week 7 due to expansion of mesoderm and apoptosis of endoderm cells.

Narrowing or blockage of the gut lumen, often caused by errors in gut tube re-canalization.

Organs attached to the body wall and not suspended by a mesentery.

Organs suspended by a mesentery, allowing movement and flexibility.

The region of the foregut that develops into the esophagus and trachea.

The absence of a smooth muscle and connective tissue wall in the rectoanal canal, leading to an inability to pass stool.

Abnormal connections between the rectal canal and the urogenital tract, often occurring alongside anal atresia.

A condition where a segment of the colon lacks nerve cells, causing muscle spasms and blockage of stool passage.

The failure of neural crest cells to migrate and differentiate into neurons within a section of the gut.

The process by which vagal and sacral neural crest cells migrate into the hindgut wall and differentiate into neurons that control gut muscle movement.

The process where the left and right sides of the stomach grow at different rates, resulting in the formation of the greater and lesser curvatures.

A rotation of the stomach along its craniocaudal axis, moving the pyloric end superiorly.

The dorsal and ventral mesenteries of the stomach persist and develop into the greater and lesser omenta, respectively.

The pyloric sphincter, located at the caudal end of the stomach, is formed by the proliferation of smooth muscle derived from mesoderm. This process relies on various genetic factors.

A condition characterized by an abnormally thickened pyloric sphincter due to excessive smooth muscle growth. This prevents proper emptying of the stomach into the duodenum, resulting in forceful vomiting.

The liver develops from ventral foregut endoderm adjacent to the septum transversum. Signals from the septum transversum and developing heart induce this region of endoderm to become liver.

The pancreas arises from two outgrowths of foregut endoderm caudal to the developing liver: the dorsal and ventral pancreatic buds. Both buds develop into branched tubules connected to secretory acini, forming the exocrine pancreas.

Stem cells at the branch points of the pancreatic duct develop into discrete islands of vascularized endocrine tissue within the exocrine parenchyma, forming the islets of Langerhans.

The uncinate process of the pancreatic head develops from the ventral bud, while the dorsal bud gives rise to the remaining head, body, and tail of the pancreas.

The duodenum is initially derived from the foregut and midgut, and its position changes as the gut tube rotates, becoming secondarily retroperitoneal.

Failure to recanalize the duodenum during development can lead to a narrowing (stenosis) or complete blockage (atresia), resulting in bilious projectile vomiting after feeding.

The midgut forms a U-shaped loop that herniates into the umbilicus due to rapid growth, ultimately giving rise to the jejunum, ileum, cecum, appendix, ascending colon, and proximal 2/3 of the transverse colon.

The appendix, initially pointing downward, is a diverticulum that develops from the caudal loop of the midgut.

The vitelline duct connects the midgut to the yolk sac and normally disappears. Persistence of the vitelline duct can lead to Meckel's diverticula, vitelline cysts, or vitelline fistulas.

The jejunum and upper ileum are derived from the upper loop of the midgut, while the lower ileum, cecum, appendix, ascending colon, and proximal 2/3 of the transverse colon originate from the lower loop.

The midgut's U-shaped loop is oriented parallel to the embryo's axis, with a cranial and caudal loop.