1.5.3 Normal Liver Biliary Tract

Question 1

The liver takes up broken down triglycerides and packages them into what?

Answer 1

VLDL

Question 2

What side of the hepatocyte?

Answer 2

Sinusoidal surface: basal membrane (serosal)

Disse: space of Disse; basal membrane of hepatocyte with numerous microvilli extends into this space between the hepatocyte and the endothelium

En: endothelium; discontinuous and fenestrated

RBC: red blood cell

Hep: hepatocyte

Question 3

What is on the left? Right?

Answer 3

Left: Portal tract

Right: Central vein

Question 4

Which surface?

Answer 4

Left: Bile canaliculus (apical)

Right: Sinusoid (basal)

Question 5

What is the original precursor to bile acid? Where does bile acid synthesis occur?

Answer 5

Cholesterol; Liver

Question 6

What are some of the conditions in which bilirubin secretion is impaired?

Answer 6

Gilbert syndrome,

Question 7

Which side of the hepatocyte?

Answer 7

Bile Canaliculus (apical)

Question 8

Describe the concentrations of the stored bile salts in the gallbladder?

Answer 8

Question 9

What are some possible conjugations of bile acid? How does it alter the pKa?

Answer 9

Unconjugated, pKa = 5.0

Glycine conjugated, pKa = 3.9

Taurine conjugated, pKa < 1

Question 10

The hepatic vein drains to?

Answer 10

IVC

Question 11

What organ is this? What is the predominant cell type? What is the arrow on the right pointing to?

Answer 11

The Liver; Hepatocytes; Portal Tract

Question 12

Describe the process of bilirubin transport.

Answer 12

Hepatocellular bilirubin transport. Albumin-bound bilirubin in sinusoidal blood passes through endothelial cell fenestrae to reach the hepatocyte surface, entering the cell by both facilitated and simple diffusional processes. Within the cell it is bound to glutathione-S-transferases and conjugated by bilirubin-UDP-glucuronosyltransferase (UGT1A1) to mono- and diglucuronides, which are actively transported across the canalicular membrane into the bile.

Question 13

What zone is most prone to ischemia?

Answer 13

Zone 3

Question 14

What % of bile acids are recirculated? Synthesized by hepatocytes?

Answer 14

Recirculated: 90%

Synthesized: 10%

Question 15

What is the difference between phase 1 and phase 2 drug metabolism in the hepatocyte?

Answer 15

Question 16

Describe the direction of flow of blood and bile b/t the portal vein and central vein.

Answer 16

Blood: PV to CV

Bile: CV to PV

Counter current flow

• blood and bile flow in opposite directions
• minimizes energy used to transport bile acids from portal blood into bile
• however, because of the relative flows of portal blood (1.3 L/min) and bile (0.5 L/day), the concentration of BA in bile is always much greater than that in portal blood. Therefore, transport from the portal blood into hepatocytes and then into the bile canaliculus requires energy