General Liver Flashcards
What are the serum measurements for hepatocyte integrity?
- aspartate aminotransferase (AST)
- alanine aminotransferase (ALT)
- lactate dehydrogenase (LDH)
What are the tests that look for biliary excretory function?
- serum bilirubin
- urine bilirubin
- serum bile acids
What are the tests that look for damage to the bile canaliculus?
- Serum alkaline phosphatase **
- Serum gamma-glutamyl transpeptidase (GGT)
What are the tests that look for hepatocyte synthetic function?
- Serum albumin
- Coagulation factors (PT, PTT, fibrinogen, prothrombin, factors V, VII, IX and X)
- hepatocyte metabolism: serum ammonia, aminopyrine breath test
What are reversible changes in hepatocytes?
- steatosis: accumulation of fat in the liver
- cholestasis: accumulation of bilirubin in liver
What happens in hepatocyte necrosis?
- fluid flows into cell, cell swells and ruptures (lysis) when osmotic regulation is interrupted
- blebs form to carry off intracellular material to extracellular space
- macrophages cluster at sites of injury
When is hepatocyte necrosis the primary mode of death?
- in ischemic/hypoxic injury
- it’s also a big part of the response to oxidative stress
What happens during hepatocyte apoptosis?
- cell shrinks, nuclear chromatin condenses (pyknosis), fragments (karyorrhexis) and cell fragments into acidophilic apoptotic bodies
What are acidophil bodies?
- apoptotic hepatocytes; named due to deeply eosinophilic stain
What are Councilman bodies?
- the same thing as acidophil bodies, term is just specific to Yellow Fever
What is confluent necrosis?
- widespread parenchymal loss with severe zonal loss of hepatocytes
- may begin as zone of hepatocyte dropout around CENTRAL VEIN
- produces space filled with cellular debris, macrophages, and remnants of reticular meshwork
When would you see confluent necrosis in the liver?
- acute toxic injuries, ischemic injuries or viral/autoimmune hepatitis
What is bridging necrosis?
- bridging area is the zone that links central veins to portal tracts, or bridges portal tracts
- necrosis is vascular insult that leads to parenchymal extinction due to large areas of contiguous hepatocyte death
- collapse of supporting framework can occur, and cirrhosis may result
What happens in regeneration of the liver?
- the cells replicate mitotically even if adjacent cells have died
What is special about hepatocytes in regeneration?
- they are stem cell like, they can replicate even in settings of chronic injury
- stem cell replenishment isn’t a significant part of parenchymal repair!
What are ductal reactions?
when hepatocytes in patients with chronic disease reach replicative senescence and clear evidence of stem cell activation appears
What happens during scar deposition in the liver
- hepatic stellate cell converts to active form and becomes highly fibrogenic myofibroblast
How are hepatic stellate cells activated?
- by increase in expression of platelet-derived growth factor receptor beta
- by cytokines released by Kupffer cells and lymphocytes (TGFB, MMP-2, TIMP-1 and -2)
What is the normal role of the hepatic stellate cell?
- stores lipid and Vitamin A
