Histology - GI Development Flashcards
Liver, Gall Blader, and ventral part of pancreas derived from
Ventral Bud
Omphalocele
no umbilical hernia reduction, mass may include foregut structures, high rate of mortality
RA high Caudally
RA Concentration Gradient
Hypertrophic pyloric stenosis
Smooth muscle hypertrophy/hyperplasia
ilial diverticulum. ~2% of population, ~2 inches long, ~2 feet from ileocecal junction
2X2X2 rule
270 degree purpose
Places small intestin within loop of large intestine
not gut tube. From Visceral Mesoderm, intraperitoneal.
Spleen derivation
Biliary duct atresia
Failure of duct to recanalize. Intrahepatic: generally fatal, Extrahepatic: often correctable
Annular pancreas
Ventral bud encircles the duodenum. May constrict/occlude duodenum.
Colorectoanal atresia
imperforate anus
rectum & proximal anus
Anorectal canal
Midgut developmental events
Week 5 - Week 12. Physiological umbilical herniation, 270 degree counterclockwise rotation, differential growth
Pancrease source
Dorsal Pancreatic Bud
prolifertation of epithelium that closes the lumen. Completes by week 5
Occlusion
SHH & HOX
Concentric layering of the gut tube
Distal anus derived from
ectoderm, separated by pectinate line
malrotation
Left-sided colon, reverse intestinal rotation
90 CCW rotation only
Left-sided colon
greater omentum
Dorsal mesogastrium - bloody supply
Physiological umbilical herniation purpose
Accomodates expanding liver & gut tube
Reversed intestinal rotation
90 CCW, 180 CW - places large colonbehind duodenum.
Jejunal, ileal stenoses/atresia
Ischemic necrosis, herniation, volvulus (twisting)
Connects intestinal loop to yolk sac
Vitelline duct
Growth induced reopening of the lumen - completes by week 9
Recanalization
hindgut fistulas
Rectoperineal fistula, Colovaginal (rectovaginal) fistula, Colovesical (urorectal) fistula
falciform ligament & lesser omentum
Ventral mesogastrium - liver budding, ends at umbilicus
RA & HOX
Cephalocaudal differentiation
SHH High in Lumen
SHH Concentration Gradient
Remnant of vitelline duct, generally asymptomatic, but may present like appendicitis.
ileal (Meckel’s) diverticulum
Urorectal septum forms
dividing cloaca into anorectal canal and urogenital sinus.
Esophageal, gastric, duodenal stenoses/atresias
Improper recanalization - epithelial issue
hernia due to anterior body wall defect, mass not within umbilicus, lower mortality
Gastroschisis
