gross anatomy of GI system Flashcards
Viscera are classified as what?
peritoneal organs;
retroperitoneal organs
define peritoneal organs
MOBILE organs w/ mesentery and almost completely enclosed in peritoneum
define retroperitoneal organs
IMMOBILE organs that are partially covered w/ peritoneum
name major peritoneal organs (suspended by mesentery)
stomach; liver & gallbladder;
spleen, tail of pancreas;
foregut duodenum, jejunum, ileum;
appendix, transverse colon
name major secondary retroperitoneal organs (lost mesentery during development)
midgut duodenum;
head, neck, body of pancreas;
ascending, descending colon;
rectum
name major primary retroperitoneal organs (never had mesentery)
kidneys, adrenal glands, ureter;
aorta, IVC;
lower rectum, anal canal
if an occlusion of the celiac artery occurs at its origin of aorta, how will head of pancreas receive blood supply?
collateral circulation by anastomoses bw pancreaticoduodenal branches of both SMA and gasroduodenal arteries
When are the branches of celiac circulation subject to erosion?
ulcer penetrating posterior wall of stomach or posterior wall of duodenum
Which branch of celiac circulation are eroded by ulcer of posterior wall of stomach?
splenic artery
Which branch of celiac circulation are eroded by ulcer of lesser curvature of stomach?
left gastric artery
Which branch of celiac circulation are eroded by ulcer of posterior wall of 1st part of duodenum?
gastroduodenal artery
patients w/ penetrating ulcer may have pain where?
referred pain in the shoulder
how may ulcer pain cause referred pain in the shoulder?
air escapes through ulcer and stimulates peritoneum covering inferior aspect of diaphragm causing pain
contents of penetrating ulcer of posterior wall of stomach or duodenum may enter where?
omental bursa
hematemesis may result from what?
bleeding into lumen of esophagus, stomach, duodenum proximal to ligament of Treitz
hematemesis commonly caused by what?
duodenal ulcer, gastric ulcer, esophageal varices
Where are common sites of ischemic bowel infarction?
transverse colon near splenic flexure and in rectum
infarction of transverse colon occurs where?
bw distal parts of middle colic branches of SMA and left colic branches of IMA
infarction of rectum occurs where?
distal parts of superior rectal branches of iMA and middle rectal branches of internal iliac artery
Patients w/ cirrhosis of liver may develop what?
portal HTN
define portal HTN
venous blood from GI structures normally enters liver by way of portal vein=> forced to flow retrograde direction in tributaries of portal vein
Retrograde blood flow from portal HTN leads to what?
forces portal venous blood into tributaries of SVC or IVC
What forms to allow blood to bypass the liver?
portacaval anastomoses established at SVC or IVC=> umbilicus, rectum, esophagus, retroperitoneal organs
What are the portal and caval anastomoses at the umbilicus?
portal=> paraumbilical veins;
caval=> superficial veins of anterior abdominal wall
Clinical signs when umbilicus is site of anastomosis
caput medusa
Clinical signs when rectum is site of anastomosis
internal hemorrhoids
Clinical signs when esophagus is site of anastomosis
esophageal varices
Clinical signs when retroperitoneal organs is site of anastomosis
not clinically relevant
What are the portal and caval anastomoses at the rectum?
portal=>superior rectal veins (IMA);
caval=>middle and inferior rectal veins (internal iliac vein)
What are the portal and caval anastomoses at the esophagus?
portal=> gastric veins
caval=> veins of lower esophagus=> drain azygos system
What are the portal and caval anastomoses at the retroperitoneal organs?
portal=>tributaries of SMA and IMA
caval=> veins of posterior abdominal wall
Where and how is IVC formed?
level of L5 vertebra by union of common iliac veins
Is the IVC a midline structure?
no just right of midline
What drains into the IVC on the right side of the body?
renal, adrenal and gonadal veins drain directly into IVC
What drains into IVC on left side of body?
only left renal vein drains directly into IVC
What drains into the left renal vein?
left gonadal and left adrenal veins
How does the left renal vein get to the IVC?
crosses anterior aspect of aorta just inferior to origin of SMA
How might there be a backup in the renal vein?
it being compressed by aneurysm of SMA as vein crosses anterior to aorta
patients w/ compression of left renal vein may have what?
renal and adrenal HTN on the left and in males a varicocele on left
