GI embryology + basics Flashcards
esophagus, stomach, proximal duodenum
liver, gallbladder, pancreas, spleen
foregut
distal duodenum → proximal 2/3 transverse colon (to splenic flexure)
midgut
distal 1/3 transverse colon → sigmoid → upper rectum (to pectinate line)
hindgut
foregut arterial supply
celiac trunk
innervation of foregut + midgut
vagus nerve - parasympathetic
splanchnic nerve - sympathetic
midgut arterial supply
SMA
hindgut arterial supply
IMA
innervation of hindgut
pelvic splanghnic nerve - parasympathetic
lumbar splanchnic nerve - sympathetic
layers of gut wall
MSMS (inside to out)
Mucosa: epithelium (absorption), lamina propria (support), muscularis mucosa (motility)
Submucosa: Submucosal plexus (Meissner)
Muscularis externa: inner circular + outer longitudinal mm., Myenteric plexus (Auerbach)
Serosa: when intraperitoneal (adventitia when retroperitoneal)
PROJECTILE VOMIT (NON-BILIOUS) PALPABLE KNOT ("OLIVE") in pyloric region thickening of pylorus muscularis
hypertrophic pyoric stenosis
incomplete recanalization of bile duct during development of bile duct shortly after birth: DARK URINE CLAY-COLORED STOOLS JAUNDICE
extrahepatic biliary atresia
abnormal fusion of ventral + dorsal pancreatic buds → forms constricting ring around duodenum → BILIOUS VOMIT (shortly after birth)
annular pancreas
persisting remnant of vitelline duct → forms outpouch in ileum → ulcerations, bleeding
Meckel diverticulum
mickel diverticulum presentation
rule of 2's: 2 inches long 2 feet from ileocecal valve 2% of population presents within first 2 years of life may have 2 types of epithelium: gastric, pancreatic
normal 270° rotation is not complete → cecum and appendix in UPPER ABDOMEN
6 wk GA: midgut herniates through umbilical ring
10 wk GA: returns to abdominal cavity and rotates around SMA
associated with volvulus (twisting of intestine) → obstruction
malrotation of midgut
midgut development involves rotation
6 wk GA: midgut herniates through umbilical ring
10 wk GA: returns to abdominal cavity and rotates around SMA
failure of normal recanalization of lumen
present with failure to thrive
intestinal stenosis/atresia
failure of neural crest cells to migrate to colon → no peristalsis constipation abdominal distention no first meconium stool BM precipitated by DRE
Hirschsprung Disease
improper formation of urorectal septum, may cause:
rectovesical fistula (anus to bladder)
rectovaginal fistula
rectourethral fistula
anal agenesis (no anal opening)
extruding viscera COVERED by sac (sac composed of peritoneum + amnion)
liver often found protruding
other anomalies: 50%: GI, GU, CV, CNS, MSK
Omphalocele = OMG its worse!
extruding viscera NOT covered by sac
liver DOESN’T protrude
other anomalies less common: 10-15%
defect lateral to umbilicus (R>L)
gastroschisis
most common tracheoesophageal anomaly
esophageal atresia (blind pouch) distal TEF (lower esophagus binds to trachea)
watershed area of intestine:
receives blood supply from distal branches of 2 arteries (SMA + IMA)
occlusion of 1 vessel, other vessel ok → no infarction
systemic hypotension → affected first (most terminal branch of arteries)
splenic flexure
branches of celiac trunk
L gastric artery
splenic artery
common hepatic artery
branches of common hepatic artery
proper hepatic artery
right gastric artery
gastroduodenal artery
branches of gastroduodenal artery
anterior superior pancreaticoduodenal artery
right gastroomental artery
ligament that connects greater curvature of stomach to transverse colon
gastrocolic ligament
ligament that connects greater curvature of stomach to spleen
gastrosplenic ligament
ligaments cut if removing spleen (ITP, hereditary spherocytosis, trauma)
gastrosplenic ligament
splenorenal ligament
ligament that connects spleen to posterior abdominal wall
splenorenal ligament
ligament that connects less curvature of stomach to liver
gastrohepatic ligament
access lesser sac (posterior to stomach) need to cut
gastrohepatic ligament
ligament that connects connects liver to duodenum (and continuos with gastrohepatic ligament)
hepatoduodenal ligament
ligament that contains portal triad (hepatic artery, common bile duct, portal vein) and can be compressed to control bleeding
hepatoduodenal ligament
ligament that connects liver to anterior abdominal wall
falciform ligament
GI problems associated with down syndrome
duodenal atresia
Hirschsprung disease
annular pancreas
celiac disase