clinical path - liver Flashcards
functions of the liver
metabolism of body fuels storage functions detoxification synthesis of most coagulation proteins excretory function
what does the liver metabolize
- protein metabolism: albumin, globulin (not immunoglobulin)
- carbohydrate metabolism: remove glucose from portal blood
- lipid metabolism: make fatty acids, triglycerides, cholesterol, and apolipoproteins
when does serum enzyme activity increase
when the rate an enzyme enters plasma exceeds the rate of enzyme inactivation or removal from plasma
when do you see an increase in enzymes
when there are damaged cells,
induction of enzyme synthesis
cell proliferation (neoplasia)
decreased enzyme clearance (decreased renal blood flow)
or ingestion and absorption (GGT from cholesterol, ALP from bones)
what enzymes are released from damaged hepatocytes
ALT
AST
SDH
GLDH
What enzymes are associated with cholestasis
ALP
GGT
what are the four liver products
urea, glucose, albumin, cholesterol
what are some hepatobiliary causes of increased liver enzymes
hypoxia, metabolic disease, toxicoses, inflammation, neoplasia, trauma, or intrahepatic/extrahepatic bile duct obstruction
what are some extrahepatic causes of increased liver enzymes
endocrine disease, Gi disorders, systemic infections, or drug indication
ALT
sensitive indicator of hepatocellular injury, but not specific (found in small amounts of muscle too)
what species can you use ALT
Useful in cats and dogs
not useful in ruminants and horses
AST
an unspecific enzyme produced by the liver, muscle, and erythrocytes during hemolysis
SDH
primary liver enzyme for horses. can also use in ruminants. unstable in vitro, need to run sample immediately
GLDH
liver-specific enzymes helpful in detecting hepatocellular injury/necrosis of large animals/ dogs
explain cholestasis
interruption or obstruction of the bile flow or excretion. can be intrahepatic (bile caniliculi and bile ducts) or extrahepatic (gall bladder and common bile duct)
may result in release of ALP and GGT