Liver Function and Laboratory Diagnosis of Liver

• What is the largest organ of the gastrointestinal tract?

  Liver
• What is a key ability of the liver regarding its cells?

  It can regenerate cells after injury
• What is the weight range of a normal liver?

  1. 2-1.5 kg
• Where is the liver located in the body?

  Underneath and attached to the diaphragm
• How is the liver divided anatomically?

  Into left and right lobes
• Which lobe of the liver is larger?

  The right lobe is approximately 6x larger
• What are the two main sources of blood supply to the liver?

  Hepatic artery and portal vein
• What type of blood does the hepatic artery supply?

  Oxygen-rich blood
• What percentage of blood supply does the portal vein provide?

  About 75%
• What is the average blood flow to the liver per minute?

  1500 mL per minute
• What are the structural units of the liver responsible for metabolic functions?

  • Lobules
• What are the two types of cells found in the liver?

  Hepatocytes and Kupffer cells
• What functions do hepatocytes perform?

  Metabolic, endocrine, and secretory functions
• What is the role of Kupffer cells in the liver?

  They are active phagocytes
• What are the major functions of the liver?

  • Excretion/Secretion
  • Metabolism
  • Detoxification
  • Storage
• What are the three systems that comprise normal liver function?

  • Hepatocytic System
  • Biliary System
  • Reticuloendothelial System
• What does the hepatocytic system deal with?

  Metabolic reactions and protein synthesis
• What is the primary function of the biliary system?

  Metabolism of bilirubin and bile salts
• What does the reticuloendothelial system concern itself with?

  Immune system and heme production
• What is the major heme waste product removed by the liver?

  Bilirubin
• What is bile composed of?

  Bile acids, salts, pigments, and cholesterol
• How much bile does the liver produce per day?

  3L per day
• How much bile is excreted by the liver per day?

  1L per day
• What is the lifespan of red blood cells (RBC)?

  120 days
• What happens to hemoglobin after RBC destruction?

  It is broken down into heme and globin
• What is transferrin's role in iron transport?

  It binds iron and transports it to the liver
• What is the process of converting heme to unconjugated bilirubin?

  Heme is converted to unconjugated bilirubin in 2-3 hours
• What happens to unconjugated bilirubin in the liver?

  It is conjugated and becomes conjugated bilirubin
• What enzyme is responsible for the conjugation of bilirubin?

  Uridyldiphosphate glucoronyl transferase (UDPGT)
• What is the fate of conjugated bilirubin after being secreted from liver cells?

  It goes to bile canaliculi and hepatic ducts
• What happens to conjugated bilirubin in the intestine?

  It is converted to mesobilirubin by intestinal bacteria
• What is urobilinogen?

  A colorless product formed from mesobilirubin
• What percentage of urobilinogen is oxidized to urobilin/stercobilin?

  80%
• What color does urobilin give to stool?

  Brown
• What are the reference values for bilirubin levels?

  • 0 - 0.2 mg/dL Conjugated Bilirubin
  • 0.2 – 0.8 mg/dL Unconjugated Bilirubin
  • 0.2 – 1 mg/dL Total Bilirubin
• How does the liver utilize carbohydrates?

  It uses glucose for energy and circulation
• What role do lipids play in liver metabolism?

  They gather free fatty acids from the diet
• What is the liver's role in protein metabolism?

  It synthesizes proteins except immunoglobulins
• What is the first pass mechanism in detoxification?

  Substances must pass through the liver first
• What are the two mechanisms of detoxification in the liver?

  Bind to inactivate or chemically modify compounds