LFTs Flashcards
- List some functions of the liver.
Intermediary metabolism Protein synthesis Xenobiotic metabolism Hormone metabolism Bile synthesis Reticulo-endothelial system
- Define intermediary metabolism.
Enzyme-catalysed processes within cells that extract energy from nutrient molecules and use that energy to construct cellular components.
- List some examples of processes that count as intermediary metabolism.
Glycolysis Glycogen storage Gluconeogenesis Amino acid synthesis Fatty acid synthesis
- List some metabolic consequences of liver failure.
Reduction in blood sugar due to a lack of glycogen Lactic acidosis (reduced ability to metabolise lactic acid) Increased ammonia (no longer able to process amino acids)
- What are the main stages of xenobiotic metabolism in the liver?
Chemical modification (e.g. redox, acetylation by CYP450 enzymes)
Conjugation (glucuronidation or sulphation)
Excretion
- Outline the roles of the liver regarding hormone metabolism.
Vitamin D hydroxylation Steroid hormones (conjugation and excretion) Peptide hormones (catabolism)
- What are the constituents of bile?
Water Bile acids/salts Bilirubin Phospholipids Cholesterol Proteins Drugs and metabolites
- What are the functions of bile?
Excretion
Micelle formation
Digestion
- Describe the metabolism and excretion of bilirubin.
Red cells are broken down to produce haem, iron and globin
Heme breaks down to form bilirubin
Bilirubin is bound to albumin in plasma
This unconjugated bilirubin travels to the liver where it becomes glucuronidated
The conjugated bilirubin is released into the bile
- What are the roles of Kupffer cells?
Clearance of infection and lipopolysaccharide (LPS) Antigen presentation Immune modulation (e.g. cytokine production)
- What are the main markers of liver synthetic function?
Albumin
Prothrombin time
- Where is ALT and AST found?
Within the cytoplasm of hepatocytes
- What is the function of ALT and AST?
Catalyse the transfer of alanine and aspartate to the alpha-keto group of alpha-ketoglutarate, thereby producing pyruvate and oxaloacetate
- Other than the liver, where else is ALT and AST found?
Muscle, kidney, bone, pancreas
- Describe the rise in ALT and AST seen in alcoholic liver disease.
AST: ALT > 2:1 in alcoholic liver disease
- What is the role of gamma-glutamyl transferase?
Catalyses the transfer of gamma-glutamyl groups between peptides
- Where is GGT found?
Hepatocytes and epithelium of small bile ducts
NOTE: also found in kidney, pancreas, spleen, heart, brain and seminal vesicles