GI blood supply Flashcards
What is superior mesenteric artery syndrome?
transverse portion of the duodenum is entrapped btw the SMA and the aorta. causes intestinal obstruction.
foregut parasympathetic innervation and vertebral level of artery
vagus; celiac at the T12/L1 level
midgut parasympathetic innervation and vertebral level of artery
vagus; SMA at the L1 level
hindgut parasympathetic innervation and vertebral level of artery
pelvic parasympathetics; IMA at the L3 level
vertebral level of aorta bifurcation
L4
esophageal varices: what is the portal/systemic anastamoses?
left gastric vein and the espohageal veins
caput medusae: what is the portal/systemic anastamosis?
paraumbilical vein and the small epigastric veins of the anterior abdominal wall (systemic)
anorectal varices: what is the portal/systemic anastamosis?
superiro rectal (portal) and the middle and inferior rectal (systemic)
How would you treat portal hypertension permanently?
create a transjugular intrahepatic portosystemic shunt (TIPS) btw the portal vein and the hepatic vein. this brings blood into the systemic circulation.
What is the pectinate line?
aka dentate line. describes the place where the hindgut (endoderm) joints with the ectoderm
what pathology may be seen above the pectinate line? What are the characteristics of this pathology?
adenocarcinoma, internal hemorrhoids. this area receives visceral innervation, so internal hemorrhoids are not painful.
What is the arterial supply and venous drainage above the pectinate line? What is the lymphatic drainage?
artery: superior rectal artery, from the IMA
vein: superior rectal vein –> inferior mesenteric vein –> portal system
lymphatics: deep lymph nodes
What pathology exists below the pectinate line? comparison with pathology above the pectinate line?
squamous cell carcinoma, anal fissure, external hemorrhoids
this area is innervated by the inferior branch of the pudendal nerve, so these hemorrhoids are painful (somatic innervation)
What is the arterial supply, venous drainage, and lymphatic drainage below the pectinate line?
artery: inferior rectal (from internal pudendal artery)
venous drainage: inferior rectal vein –> internal pudendal vein –> internal iliac vein –> IVC
lymph drainage: internal iliac
What are anal fissures?
teas below the pectinate line. cause pain with defecation and bright red blood on toilet paper. these are located posteriorly becuase this area is poorly perfused.
