Liver Function Flashcards
3 functions of the liver
- Protein metabolism
- proteins such as albumin and Igs synthesised - Carbohydrate metabolism
- glucose stored as glycogen - Fat metabolism
Liver biosynthetic functions: albumin
Major plasma protein
T1/2 of 21 days
Key role in maintaining intravascular colloid osmotic pressure (pressure resulting from difference between ECF & plasma/interstitial fluid protein content) ie be able to hold water in blood vessels.
Decrease in albumin = decrease in on oncotic pressure (water leaves blood vessels & collects in tissues leading to oedema & swelling)
Fall in albumin => chronic liver disease
Liver biosynthetic functions: clotting factors
Prothrombin (factor II) (so increased bleeding risk in those with liver disease)
Name a sensitive marker for liver disease
International normalised ratio - measure of blood clotting time
Liver biosynthetic functions: give an example of a hormone binding protein that the liver produces
Ceruloplasmin
What causes ascites?
Scar tissue -> prevents free blood flow through liver -> blood backup in portal vein -> blocks lymph channels -> lymph spills into abdomen (peritoneal cavity)(also cased by low albumin)
Ascites can also be caused by low ________ levels.
Albumin
Constituents of bile
Bile salts
Water
Electrolytes
Cholesterol
Phospholipids
Bilirubin
Small amount of protein
Where are bile acid metabolites synthesised?
Synthesised in liver cells from cholesterol
Function of bile salts
Acts as a detergent - lipid solubilisation
Where is bile stored?
gallbladder
Most bile salts reaching ___ are re absorbed in terminal _____ & returns to ______ via ___________.
Gut
Ileum
Liver
Portal vein
Where does the majority of bilirubin come from?
Breakdown of Hb
Haem converted to _________ by oxygenation.
Biliverdin
Biliverdin is ______ to bilirubin.
Reduced
__________ bilirubin bound to albumin - transported to liver.
Unconjugated
Glucuronicated _________ secreted via AT, some secreted via gut. Most oxidised to ____________ and secreted in urine.
Bilirubin
Urobillinogen
What are the three types of jaundice?
Pre-hepatic (haemolytic)
Hepatic or Hepatocellular (intrahepatic cholestasis)
Post-hepatic or obstructive (extraheptic cholestasis)
Features of pre-hepatic jaundice
Fault upstream of conjugation
- excess haemolysis => increased bilirubin load
- fragile cells or immune attack
Unconjugated bilirubin increased
- liver unable to handle the increased bilirubin load
No bilirubin in urine
Features of hepatic jaundice (hepatocellular jaundice)
Failure of conjugating system
Results from disease/damage to the liver such as cirrhosis or hepatitis
Both conjugated and/or Unconjugated bilirubin can be increased
Features of post-hepatic jaundice (cholestatic jaundice)
Obstruction to flow of bilirubin from liver
Mainly increased conjugated bilirubin
Faeces are pale
Urine is dark
Gallstones
Cancer of pancreas
Causes of liver injury
Infection
Drugs
Toxins
Tumours
AIDs
Classification liver damage by site:
Hepatocellular disease
Cholestatic disease
Features of hepatocellular disease
Direct damage to liver cells
Causes include:
- alcohol
- hepatitis
- toxins e.g. NSAIDs
