Development of the Abdomen Flashcards
Stomach Development
Begins as a dilation in the gut tube and the dorsal surface will grow fast and rotate 90 degrees clockwise making the greater curvature end up on the left
*This rotation leads to the formation of the lesser sac
Esophagus Formation
The respiratory diverticulum expands to form the esophagotracheal ridge which will grow inward separating the pharynx into two longitudinal tubes
Vagal Trunk Composition
Anterior is primarily left and posterior to stomach is primarily right
*Due to rotation of the stomach during development
Liver development
Begins as the hepatic diverticulum off the gut tube and pushes into the septum transversum becoming suspended in the foregut and anterior abdominal wall
*Septum transversum pulled along during development becomes the ventral mesentary
Falciform ligament
Liver to anterior abdominal wall
*Carries the abdominal vein
Central tendon of the diaphragm
Derived from the septum transversum and is in direct contact w/ the bare area of the liver
Gall Bladder development
Arises from the hepatic diverticulum; common stalk of the liver connected to the gall bladder and ventral pancreas becomes the common bile duct
Pancreas Development
Ventral pancreas arises from hepatic diverticulum and dorsal develops of the duodenum
=> Fuse in week 6; ventral bud becomes main pancreatic duct and dorsal bud becomes accessory duct
*Growth of the dorsal duodenal wall pushes the ventral pancreas and bile duct dorsally
Annular Pancreas
Congenital abnormality characterized by a ring of pancreatic tissue from the ventral bud surrounding the duodenum
*Causes intestinal obstruction
Spleen Developent
Independent condensation of mesoderm b/w the dorsal mesentary of the stomach
Gastroschisis
Ventral body wall defect causing herniation of the intestinal loops into the amniotic cavity
*Failure of body wall to close; viscera are NOT covered in peritoneum
Omphalocele
Ventral wall defect caused by failure of the intestines to return to the abdominal cavity after physiological umbilical herniation
*Intestines are covered by peritoneum
Midgut Development
During physiological umbilical herniation, the intestines rotate 90 degrees counterclockwise around the superior mesenteric artery; when the return to the abdomen, they rotate another 180 degrees and the proximal end enters the upper left part of the abdominal cavity
*Cecum forms as swelling on the caudal loop during this timeframe (4-10 weeks)
Hindgut development
The urogenital septum grows b/w the hindgut and allantois dividing the cloaca into the urogenital sinus and the anorectal canal
=> The proctodeum will push inward on the anorectal canal to form the distal opening of the tube
Pectinate Line
Separation b/w regions of the anal canal formed by the cloaca and the proctodeum `
