P39 - Liver Function Flashcards
what percentage of functional hepatocytes must be lost before clinical evidence of hepatic insufficiency
- 80%
hepatic enzymes is not ____ ____ tests
- liver function
bilirubin is produced in
- macrophages
what are the 4 types of bilirubin
- Ba - unconjugated
- Bb - bilirubin monglucuronide
- By - bilirubin diglucuronide
- Bs - delta bilirubin (degraded conjugated bound to albumin)
a measurement of direct bilirubin is all forms except
- unconjugated
hemolysis leads to an ____ formation of bilirubin
- increase
pathogenesis of extravascular hemolysis of erythrocytes and concentration of bilirubin
- is Bu or Bc greater
- 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]
decreased uptake of bilirubin pathogenesis effect on concentration of bilirubin
- is Bu or Bc greater
- 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]
in horses expect increase [Bt] within ____ hr of fasting and peak concentration within ____ days
- 12-15
- 2-3
pathogenesis of decrease transport of bile and decrease bile flow (cholestasis) [which is rate limiting?]
- is Bu or Bc greater
- 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]
in dogs, effusion of [bilirubin] is greater than ___ serum [bilirubin]
- twice
bile acids are _____ derived anionic acids and associated anions
- cholesterol
bile salts are ____ forms
- anion
in heath there is ____ BA (bile acid) in systemic blood
- very little
- decrease functional mass
- portosystemic shunt
- obstructive cholestasis
- functional cholestasis
can all lead to _____ bile acid (BA) concentration
- increase
- hypercholemia
pathogenesis of decrease functional mass leading to increase bile acids (hypercholemia)
- 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)
pathogenesis of portosystemic shunt leading to increase bile acids (hypercholemia)
- decrease bile acid deliver to hepatocyte via portal blood -> decrease clearance from portal blood
pathogenesis of obstructive cholestasis leading to increase bile acids (hypercholemia)
- lesion impairs bile flow -> decrease bile acid excretion into bile -> bile acids accumulate in hepatocytes -> is regurgitated to blood
pathogenesis of functional cholestasis leading to increase bile acids (hypercholemia)
- 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
bile acid (BA) challenge test
- after 12 hour fast collect blood sample
- feed small meal
- collect sample after 2 hours
- challenges systems ability to remove BA from portal blood
bile acid (BA) challenge test is not done in what type of animals
- icteric animals
most ammonium (NH4) enters blood from ____ and ____
- intestines
- deamination of proteins in tissues
does portosystemic shunt cause hyperammonemia or hypoammonemia
- hyperammonemia
- decrease removal from portal blood
