Blood supply of the GI system Flashcards
At what level is the celiac trunk?
T12
At what level is the SMA?
L1
What branches laterally at the same level as the celiac trunk?
Inferior phrenic arteries
What branches laterally at the same level as the SMA?
Renal arteries
At what level does the IMA leave the aorta?
L3
What branches off between the SMA and IMA?
Gonadal arteries
At what level is the bifurcation of the aorta?
L4
What is the portosystemic anastomosis of the esophagus?
Left gastric (portal) to esophageal (system)
What is the clinical manifestation of esophageal anastomosis?
Esophageal varices
What is the portosystemic anastomosis of the umbilicus?
Paraumbilical (portal) to small epigastric veins of the anterior abdominal wall (systemic)
What is the clinical manifestation of umbilical antastomosis?
caput medusae
What is the portosystemic anastomosis of the rectum?
Superior rectal (portal) to middle and inferior rectal (systemic)
What is the clinical sign of rectal portosystemic anastomosis?
Anorectal varices (not the same as internal hemorrhoids!)
Where is the pectinate line of the anal canal?
Between promixal 1/3 and distal 2/3
What is the pectinate/dentate line the meeting place of?
Where endoderm (hindgut) meets ectoderm
What kind of hemorrhoid presents above the pectinate line?
Internal hemorrhoids.
Are internal hemorrhoids painful or painless?
Painless. Visceral innvervation.
What is the blood supply above the pectinate line?
Superior rectal artery (branch of IMA)
What is the venous drainage above the pectinate line?
Superior rectal vein –> inferior mesenteric vein –> portal system
What is the lymphatic drainage above the pectinate line?
Internal iliac lymph nodes
What kind of cancer presents above the pectinate line?
Adenocarcinoma.
What are the sources of bleeding that present below the pectinate line?
External hemorrhoids and anal fissures
What is an anal fissure?
Tear in the anal mucosa below the pectinate line. Presents with Pain while Pooping w/ blood on toilet Paper. Located posteriorly since this area is poorly perfused.
What kind of cancer presents below the pectinate line?
Squamous cell carcinoma.
What is the blood supply below the pectinate line?
Inferior rectal artery (branch of internal pudendal artery)
What is the venous drainage below the pectinate line?
Inferior rectal vein –> internal pudendal vein –> internal iliac vein –> common iliac –> IVC
What does the apical surface of hepatocytes face?
Bile caniculi
What does the basolateral surface of hepatocytes face?
Sinusoids
What is Zone I of the hepatic lobule?
Periportal zone - where blood arrives from intestine via portal vein, and from heart via hepatic artery.
What is Zone II of the hepatic lobule?
intermediate zone
What is Zone III of the hepatic lobule?
Pericentral vein/centrilobular zone. Central vein is tributary of hepatic vein.
Which zone of the hepatocyte is first affected by viral hepatitis?
Zone I
Which zone of the hepatocyte is first affected by ingested toxins such as cocaine?
Zone I
Which zone of the hepatocyte is first affected by yellow fever?
Zone II
Which zone of the hepatocyte is first affected by ischemia?
Zone III
Which zone of the hepatocyte contains cytochrome p450 system?
Zone III
Which zone of the hepatocyte is most sensitive to metabolic toxins?
Zone III
Which zone of the hepatocyte is the site of alcoholic hepatitis?
Zone III
In what direction does blood flow in the hepatocyte?
Zone I –> Zone III
In what direction does bile flow in the hepatocyte?
Zone III –> Zone I
What is the space of disse?
lymphatic drainage of hepatocyte
What causes cholangitis and pancreatitis at the same time?
Gallstone at the ampulla of Vater
What is the ampulla of Vater?
Confluence of common bile duct and pancreatic duct.
Where is the sphincter of oddi?
At the ampulla of vater
What do tumors that arise in the head of the pancreas cause?
Obstruction of common bile duct only; painless jaundice.
