LFTs Flashcards
What is bilirubin formed from?
Breakdown of RBC porphyrin ring
What organ does insoluble unconjugated iron travel to?
Liver
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?
In urine
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?
Jaundice
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?
ALT
AST
ALP
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?
Liver
What happens to albumin levels as liver function deteriorates?
Falls
