Mar2 M2-GI Embryology In the Trenches Part 2 Flashcards
(EXAM) foregut, midgut, hindgut where to where + their artery
foregut = pharynx to DJ junction (celiac trunk) midgut = DJ junction to splenic flexure (SMA) hindgut = splenic flexure to anus (IMA)
2 ducts and papilla of pancreas
- Wirsung (main. bigger duct): major duodenal papilla
- Santorini (accessory): minor duodenal papilla
pancreas divisum def
congenital abnormality where each bud keps it duct: minor duct (smaller) is the main one and too narow for flow
(surgery to make papilla bigger)
dx of pancreas divisum
ERCP (cannulation of major papilla, dye)
annular pancreas def
bifid ventral bud wraps around duodenum
liver development
liver, GB and bile ducts arise from a ventral outgrowth of the caudal foregut (week 4): hepatic diverticulum extends in septum transversum and divides in 2 parts
2 parts of hepatic diverticulum in septum transversum and what they form
large cranial part = primordium of the liver
small caudal part = gallbladder
what happens to common bile duct during ventral pancreas rotation
ventral rotates anteriorly but CBD rotates posteriorly and so now crosses behind the duodenum from right to left
extrahepatic biliary atresia def
atresia (scarring down) of some bile ducts: jaundice and obstruction in first 3 months after birth
extrahepatic biliary atresia cause and treatment
failure of bile ducts to recanalize. bypass of porta hepatis to bowel (so bile goes there directly)
choledochal cyst def
prob in infants or neonates: cystic dilations of CBD: jaundice, cholangitis (bile infection), cysts
choledochal cyst treatment + prognosis compared to extrahepatic biliary atresia
bypass surgery (put bowel right below liver so bile goes there directly). much better prognosis than extrahepatic biliary atresia
congenital omphalomesenteric duct def
failure of yolk sac stalk to obliterate and disappear. many anomalies. most common is Meckel’s diverticulum
possible problem in Meckel’s diverticulum
bowel obstruction bc twisting around
other complications of Meckel’s diverticulum
- subumbilical mass (cyst forming around belly button)
- umbilical polyp (of intestinal mucosa. gets there bc of omphalomesenteric duct)
cause of most jejunum and ileal problems congenital
vascular accidents (vessels in mesentery thrombose for some reason and disappear. ischemia of bowel. may happen in utero 20 wks)
type 1 jejuno-ileal atresia
one dilated bowel part and one collapsed part. membrane interface between the two
type IIIb jejuno-ileal atresia
curly bowel, appel core deformity, lot of bowel loss
types 2, IIIA and 4 jejuno-ileal atresia
2 = defect in bowel
IIIA = mesentery gone + distance in separation
type 4 = many pieces
surgery for jejuno-ileal atresia
remove obstruction and put bowel parts together
what the hindgut forms
- colon from splenic flexure to anal canal
- epithelium of urinary bladder and most of urethra
cloaca def
terminal part of hindgut. endoderm-lined chamber where hindgut and urinary system share space. receives allantois (diverticulum of the yolk sac)
septum in cloaca
urorectal septum: separates the 2 systems in the cloaca. comes close to skin, near allantoic membrane
urorectal septum in development (CLOACAL PARTITIONING steps)
comes down and fuses with cloacal membrane to form dorsal part (anal membrane) and ventral part (urogenital membrane)
