Flashcards in LFTs Deck (49)
What is bilirubin formed from?
Breakdown of RBC porphyrin ring
What organ does insoluble unconjugated iron travel to?
How does insoluble unconjugated iron travel to the liver?
Bound to albumin
What happen to insoluble unconjugated bilirubin at the liver?
Liver enzymes conjugated it to form bilirubin glucuronide (conjugated bilirubin)
How is conjugated bilirubin excreted?
In bile = soluble
How can conjugated bilirubin be excreted directly?
What happens to conjugated bilirubin in bile?
It is broken down in the gut into urobilinogen (some reabsorbed and excreted by the kidney) and stercobilinogen (forms brown colour of stool)
What sign can increase bilirubin cause?
At what level of bilirubin would jaundice be visible?
>35 micro mol/L
What are the 4 liver enzymes?
Alanine transaminase (ALT)
Aspartase transaminase (AST)
Alkaline phosphate (ALP)
Gama glutanyl transferase (GGT)
What are the 3 intracellular liver enzymes?
What happens to ALT when liver cells damaged?
Release from liver into blood stream
Is ALT specific?
Yes, found almost exclusively in the liver
Is AST specific?
Not as much as ALT - also found in cardiac tissue and muscle
What happens to AST when liver cells damaged?
Released from liver into blood stream
Where is ALP found?
Mainly in liver and bone
What is the function of ALP?
Involved in transport of substances across the cell membrane
Why might ALP be raised?
Physiologically - metabolically active cells e.g. bones growing, pregnant
Bile drainage obstructed
Where is ALP found in the liver?
In cells near the bile ducts sad canaliculae
Where is GGT found in the liver?
In hepatocytes and biliary epithelial cells
What is the purpose of GGT?
Plays a role in the metabolism of drugs
Name 2 conditions which cause a rise in GGT?
Alcohol and certain drugs
Bile duct obsturction
Where is albumin synthesised?
What happens to albumin levels as liver function deteriorates?
Apart from liver function, name 3 other causes of low albumin levels?
What happens to prothrombin time if liver problem?
What causes pre-hepatic jaundice?
Increased breakdown of RBCs
What causes intra-hepatic jaundice?
Problem in the liver
What causes post-hepatic jaundice?
Bile duct system damaged/ obstructed = unable to move bile into digestive tract
Bilirubin in prehepatic jaundice?
AST/ ALT in prehepatic jaundice?
ALP in prehepatic jaundice?
Haemoglobin in prehepatic jaundice?
Jaundice in prehepatic jaundice?
Urine in prehepatic jaundice?
Bilirubin in intrahepatic jaundice?
AST/ ALT in intrahepatic jaundice?
ALP in intrahepatic jaudnice?
Hb in intrahepatic jaundice?
Jaundice in intrahepatic jaudnice?
May be marked
Other name for post hepatic jaundice?
Bilirubin in posthepatic jaundice?
AST/ ALT in posthepatic jaundice?
ALP in posthepatic jaundice?
Hb in posthepatic jaudnice?
Jaundice in posthepatic jaundice?
May be marked
Stool in posthepatic jaudnice?
What effect on stool does bilirubin have?
Make it darker -> pale stool = lack of bilirubin in GI tract