Embryology of GI System Flashcards
Foregut
esophagus, stomach, 1/2 duodenum, liver gallbladder, pancreas, spleen
Blood supply to foregut
celiac artery
Preganglionic sympathetic innervation of foregut
T5-T9
Preaortic ganglion sympathetic innervation for foregut
celiac
Postganglionic axons of sympathetic foregut
celiac artery
Preganglionic parasympathetic innervation for foregut
brainstem
Parasymp innervation for foregut
vagus n
Location of parasymp foregut ganglia
organ walla
Midgut organs
1/2 duodenum, jejunum, ileum, cecum, appendix, ascending colon, 2/3 transverse colon
Blood supply to the midgut
superior mesenteric artery
Preganglionic sympathetic innervation for midgut
T9-T12
Preaortic ganglion for sympathetic midgut
superior mesenteric
Postganglionic axons for sympathetic midgut
superior mesenteric a
Preganglionic bodies for parasymp midgut
brainstem
Parasymp innervation for midgut
vagus n
Hindgut organs
1/3 transverse colon, descending colon, sigmoid colon, rectum, upper anal canal
Blood supply for hindgut
inferior mesenteric a
Preganglionic bodies for sympathetic innervation
T12-L2
Preaortic ganglion for sympathetic hindgut
Innferior mesenteric
Postganglionic sympathetic innervation for hindgut
inferior mesenteric a
Preganglionic bodies for parasymp hindgut
S2-S4
Nerves for parasymp innervation
pelvic splanchnic nerves
Retinoic acid in GI development
creates gradient and for certain transcription factors to be expressed in different areas of the gut
Proximal to distal concentration of distal gut tube
Increasing retinoic acid
Sonic Hedgehog in gut tube development
initiates interaction between epithelium and mesenchyme
Where is epithelium derived from
endoderm
Where is mesenchyme derived from
splanchnic mesoderm
What is derived from the endoderm
epithelium and glands
What is derived from splanchnic mesoderm
lamina proria, submucosa, muscularis layers, serosa/adventitia
What mesesntery is the gut tube suspended by?
doral
What forms from the ventral mesentery
from developing liver- falciform ligament, lesser omentum
What does the esophagus form from
laryngeotracheal diverticulum
How does tracheoesophageal fistula form
failure of tracheoesophageal septum to fuse completely and separate respiratory and GI system
What occurs with an esophageal atresia
esophagus ends in blind pouch
Esophageal stenosis
narrowed esophagus
Esophageal atresia
occluded esophagus
What can occur due to incomplete recanalization
esophageal stenosis or atresia
3 ways for esophageal replacement
colon interposition, gastric tube esophagoplasty, gastric transposition
Coloninterposition
section of colon taken and joined to esophagus above and stomach below
Gastric tube esophagoplasty
longitudinal segment from stomach is pulled up into chest and joined to esophagus
Gastric transposition
whole stomach freed and moved into thoracic cavity and attached to upper end of esophagus
Corkscrew esophagus
esophagus shows corkscrew appearance
Zenker’s diverticulum
out pocketing of esophagus between constrictor muscles that can get food or fluid trapped in it
Which part of the stomach develops from the dorsal mesentery
greater curvature
Which part of the stomach develops from the ventral mesentery
lesser curvature
Which side of the stomach grows faster
dorsal side (left)
Hypertrophic pyloric stenosis
2-3 weeks after birth, projectile vomit with no bile , scaphoid abdomen
Double bubble sign
duodenal atresia- air in stomach and into duodenum
What mesentery do the liver, gallbladder, and bile ducts develop in
ventral mesentery
Molecular regulation of liver by
FGF2 and BMP
Growth of the liver divides ventral mesentery into..
falciform ligament and lesser omentum
Ligamentum venosum is a fibrous remnant of…
ductus venosus
Legamentum terest hepatis is remnant of…
Left umbilical vein
S/S of extrahepatic biliary atresia
jaundice, dark urine, pale stool
Cause of extrahepatic biliary atresia
incomplete canalization of bile duct
Major regulators of the pancreas
Islets of langerhan
Which pancreatic bud makes minor papilla
dorsal
Which pancreatic bud makes major papilla
ventral
Rotation and fixation of midgut
normal physiologic herniation, gut loops into umbilical cord, loop rotates 90 degrees around SMA
Volvulus
abnormal twisting of the intestine causing obstruction
Bilious Emesis
starts throwing up bile vomit (green)
What can cause bilious emesis
malrotation within volvulus `
Intussusception
enfolding of one segment of intestine within another
Omphalocele
herniation of gut tube that doesn’t come back and is covered by umbilical cord
Gastroschisis
herniation of gut tube not covered by umbilical cord
How does gastroschisis occur
failure of anterior abdominal wall musculature to close during folding
Prune Belly
anterior abdominal wall is deficient of absent
Ileal/Meckel’s diverticulum is a remnant of..
vitelline duct
Rule of 2’s
location 2 feet proximal to ieocecal valve in adults, half of those who are symptomatic are younger than 2 years of age
What happens during an umbilical hernia
gut pushes skin and fascia out ahead of it
Hirschsprung’s disease
megacolon- large pockets of feces in part of colon that doesn’t work
What is the only proven treatment for Hirschsprung’s disease
surgery
Defects in partitioning of the cloaca
rectourethral fistula (or rectoprostatic/rectovaginal)
Low anorectal malformation
anal canal ends as bind sac below pelvic diaphragm
High anorectal malformation
rectum ends as a blind pouch above the pelvic diaphragm
