Hello and welcome back to Ackrack. I'm Jed Wolpeck and today we're going to talk about another very highly tested topic and that is liver physiology and the liver in general.

Please note that we've already done other episodes on liver transplant specifically so this

will not be about how to do a transplant or the physiology

intraoperatively during a liver transplant. This is going to be about patients with liver

disease, how they behave, what we need to think about, and the physiology you might

be tested on and you'll want to know.

All right, so let's talk about some of the basics, blood flow.

So you'll want to remember because these are the kind of little facts we learned in

med school but that get tested, they come up on tests, right?

The blood flow to the liver.

So 25% of the entire cardiac output goes to the liver. The portal vein supplies 75% of the

blood to the liver and the hepatic artery supplies the other 25%. So there's that dual supply

of blood. but remember that they both supply about half

of the oxygen so this can be tricky they the portal van supplies 75% of the

blood the hepatic artery 75% of the blood, the hepatic artery blood is richer in

oxygen, they each supply 50% of the oxygen that the liver needs.

There's relatively high flow through that system, especially the portal vein, much higher

than a normal vein, and that's because there's low resistance. So average portal

pressure is about 8 to 10 which compares to hepatic venous pressure of

only 4 to 5 so there's that gradient pushing it forward. Now of course what happens when

hepatocytes get injured is they get replaced over time by fibrous tissue

which impedes flow and that means portal pressures have to increase in order to

...