Liver Function Flashcards
Why is the liver resilient?
It can regenerate cells destroyed by short time injury or disease
Name the two types of liver cells
Hepatocytes and Kuppfer cells
What is the bile canaliculi?
The small spaces between hepatocytes that form intrahepatic ducts where excretory products of the cells can drain
What are the role of Kuppfer cells?
Macrophage cells that line sinusoids - act as phagocytes to engulf bacteria, debris and toxins
List the 5 major functions of the liver
- Metabolic
- Synthetic
- Storage
- Detoxification
- Excretory/digestive
Give examples of metabolic functions of the liver
Carbohydrate metabolism - releases glucose by breaking down glycogen, stores glycogen
Protein metabolism - plasma proteins
Lipid metabolism and cholesterol
Give an example of the synthesis function of the liver
Synthesises plasma proteins (albumin, clotting factors, c-reactive proteins)
Give examples of the storage function of the liver (what does it store)
Iron, amino acids, glycogen, some vitamins (A, D, B12) and temporary lipid storage
Give examples of the detoxification function of the liver
Detoxifies GIT metabolites, drugs, alcohol and paracetemol
Give an example of the excretory/digestive function of the liver
Degrades bilirubin and removes excess cholesterol through bile
What is bilirubin?
A bile pigment derived from the breakdown of red blood cells
How is bilirubin transported to the liver?
By attaching to albumin in plasma (blood)
Define total bilirubin.
The sum of conjugated + unconjugated bilirubin
Define jaundice and what symptoms occur
A condition of increased serum bilirubin levels and it’s deposition in the skin, mucous membranes and sclera (White of the eye) - characterised by yellow colouring (icterus)
What are the 3 types of jaundice
- Pre hepatic jaundice - problem occurs before the liver
- Hepatic jaundice - problem occurs in liver
- Post hepatic jaundice - problem occurs after liver
What is prehepatic jaundice and what is it caused by
Occurs prior to liver metabolism - caused by malaria, sickle cell disease or haemolytic disease of the newborn
What is intrahepatic jaundice and what are the 3 types
Problem resides in the liver due to 1) hepatocelluar damage, 2) inherited hyperbilirubinemia, or 3) Neonatal physiological jaundice in newborn
Define neonatal physiological jaundice
Transient (short term) immaturity of the liver = delay in being able to produce the UDPG transferase enzyme for conjugation of bilirubin
Prehepatic jaundice will lead to what pathophysiological states?
Increased plasma bilirubin
Increased unconjugated bilirubin
Increased urine urobilinogen
Posthepatic jaundice will lead to what pathophysiological states?
Increased conjugated bilirubin Increase plasma bilirubin Increased plasma GGT and ALP Decreased urine urobilinogen Positive urine bilirubin
Define posthepatic jaundice
Partial or complete obstruction of the biliary tree preventing flow of conjugated bilirubin into bile canaliculi therefore unable to reach the gut (stools are clay coloured due to bilirubin not reaching gut)
What are the 3 types of liver function tests?
- Function - albumin, clotting, bilirubin
- Damage - enzyme assays
- Cholestasis - enzyme assays
What are the different tests to measure liver function?
- tests that measure hepatic cellular ability
- tests that measure nitrogen metabolism
- tests that measure bilirubin metabolism
What molecules are tested for in hepatic cellular ability tests
albumin - decreased in chronic liver disease (not useful for acute due to its long half life)
prothrombonin time - increased in liver disease due to inadequate production of clotting factors or inadequate absorption of vitamin K from intestine due to disruption of bile flow
lipids - hepatic disorders often disrupt lipoprotein metabolism (not liver specific)
