GI Embryology II Flashcards
What does the pancreas develop from?
Ventral and dorsal pancreatic buds (endoderm)
What structures in the pancreas come from the ventral side? Dorsal side?
Ventral: Head and uncinate process
Dorsal: Everything else
Which pancreatic duct becomes the definitive pancreatic duct (Duct of Wirsung)?
Duct of the ventral pancreas
What structures form the exocrine pancreas?
Acini
What structures become the endocrine pancreas?
Islets of langerhans and ducts
What structure from an ileal diverticulum
Omphaloenteric duct (yolk stalk)
What structure serves as the axis for GI tract rotation during umbilical herniation?
Superior mesenteric artery
What direction is the rotation during umbilical herniation?
270º rotation counter-clockwise
What does histological examination of Meckel (ileal) diverticulum look like?
Pancreatic tissue, stomach tissue, intestinal tissue all in one
What developmental feature is responsible for a Gastroschisis?
Abnormal lateral body wall folding
What developmental feature is responsible for a congenital omphalocele?
Physiological umbilical herniation
If rotation does not occur, where does the large intestine sit in relation to the small intestine?
To the left
What structures are derived from the dorsal mesentery?
Transverse mesocolon
Mesentery
Greater ometum
Sigmoid mesocolon
What is the cloaca?
Caudal end of hindgut and the base of urogenital sinus
What does the cloacal membrane separate?
Cloaca from proctodeum
What embryological tissue gives rise to the urorectal septum?
Mesenchyme
What does the urorectal septum separate? What does the separated structure become?
Cloacal membrane into urogenital membrane and anal membrane
The fusion of the urorectal septum and cloacal membrane becomes what?
Perineal body
What derives the upper two thirds of the anal canal? The lower third?
Upper 2/3: Hindgut
Lower 1/3: Proctodeum
What line separates the hindgut/proctodeum derived anal canal?
Pectinate line
What vessel supplies the proctodeum?
Inferior rectal branch of internal pudendal
What vessel supplies the handgun?
Inferior mesenteric
Where do lymphatics from the hindgut drain?
Inferior mesenteric nodes
Where do lymphatics from the proctodeum drain?
Superficial inguinal nodes
