P39 - Liver Function

Question 1

what percentage of functional hepatocytes must be lost before clinical evidence of hepatic insufficiency

Answer 1

• 80%

Question 2

hepatic enzymes is not ____ ____ tests

Answer 2

• liver function

Question 3

bilirubin is produced in

Answer 3

• macrophages

Question 4

what are the 4 types of bilirubin

Answer 4

• Ba - unconjugated
• Bb - bilirubin monglucuronide
• By - bilirubin diglucuronide
• Bs - delta bilirubin (degraded conjugated bound to albumin)

Question 5

a measurement of direct bilirubin is all forms except

Answer 5

• unconjugated

Question 6

hemolysis leads to an ____ formation of bilirubin

Answer 6

• increase

Question 7

pathogenesis of extravascular hemolysis of erythrocytes and concentration of bilirubin
- is Bu or Bc greater

Answer 7

• increase rate of formation of bilirubin (unconjugated) -> incomplete removal of bilirubin by hepatocytes
• increase conjugation of bilirubin in hepatocytes -> rate of Bc formation exceeds Bc excretion to bile -> conjugated regurgitated to plasma
• [Bu] > [Bc]

Question 8

decreased uptake of bilirubin pathogenesis effect on concentration of bilirubin
- is Bu or Bc greater

Answer 8

• conversion of stored triglycerides to fatty acids (FA) -> increase fatty acids delivery to hepatocytes -> fatty acids bind to Z-protein -> decrease ligands available for binding unconjugated bilirubin -> decrease uptake of unconjugated bilirubin by hepatocytes
• [Bu] > [Bc]

Question 9

in horses expect increase [Bt] within ____ hr of fasting and peak concentration within ____ days

Answer 9

• 12-15

- 2-3

Question 10

pathogenesis of decrease transport of bile and decrease bile flow (cholestasis) [which is rate limiting?]
- is Bu or Bc greater

Answer 10

• decrease transport of bile is rate limiting step
• impaired bile flow -> decrease Bc transport to canaliculi and increase Bc transport to sinusoids -> Bc returns to plasma -> increase Bc interferes with uptake of Bu
• [Bc] > [Bu]

Question 11

in dogs, effusion of [bilirubin] is greater than ___ serum [bilirubin]

Answer 11

• twice

Question 12

bile acids are _____ derived anionic acids and associated anions

Answer 12

• cholesterol

Question 13

bile salts are ____ forms

Answer 13

• anion

Question 14

in heath there is ____ BA (bile acid) in systemic blood

Answer 14

• very little

Question 15

• decrease functional mass
• portosystemic shunt
• obstructive cholestasis
• functional cholestasis
  can all lead to _____ bile acid (BA) concentration

Answer 15

• increase

- hypercholemia

Question 16

pathogenesis of decrease functional mass leading to increase bile acids (hypercholemia)

Answer 16

• progressive liver disease or hepatic atrophy -> too few hepatocytes to remove BA from portal blood -> decrease BA clearance from portal blood -> BA pass through liver to central vein (systemic blood)

Question 17

pathogenesis of portosystemic shunt leading to increase bile acids (hypercholemia)

Answer 17

• decrease bile acid deliver to hepatocyte via portal blood -> decrease clearance from portal blood

Question 18

pathogenesis of obstructive cholestasis leading to increase bile acids (hypercholemia)

Answer 18

• lesion impairs bile flow -> decrease bile acid excretion into bile -> bile acids accumulate in hepatocytes -> is regurgitated to blood

Question 19

pathogenesis of functional cholestasis leading to increase bile acids (hypercholemia)

Answer 19

• inflammatory disease that cause release of TNFa -> increase in TNFa cause decrease transport of BA into canaliculi -> decrease bile acid excretion into bile -> bile accumulate in hepatocytes -> regurgitated to blood

Question 20

bile acid (BA) challenge test

Answer 20

• after 12 hour fast collect blood sample
• feed small meal
• collect sample after 2 hours
• challenges systems ability to remove BA from portal blood

Question 21

bile acid (BA) challenge test is not done in what type of animals

Answer 21

• icteric animals

Question 22

most ammonium (NH4) enters blood from ____ and ____

Answer 22

• intestines

- deamination of proteins in tissues

Question 23

does portosystemic shunt cause hyperammonemia or hypoammonemia

Answer 23

• hyperammonemia

- decrease removal from portal blood