Bile

Describe the physiology of bile and its metabolism

Bile is a dark green solution produced by the liver to facilitate absorption of fat and fat-soluble vitamins (ADEK) through emulsification. Bile is:

• Produced by the liver at the rate of 1L per day
• Concentrated in the gallbladder
• Important in the absorbance of lipid and fat-soluble vitamins
• Formed from:
  • Water
  • Protein
  • Bilirubin
  • Bile salts
    The sodium and potassium salts of bile acids. Bile acids:
    • Are are produced from cholesterol
    • Are amphipathic, and act as emulsifiers of lipid
      Break up large fat globules into smaller micelles, which can then be absorbed.
    • Major bile acids include:
      • Cholic acid
      • Chenodeoxycholic acid
    • Are absorbed in the terminal ileum, and recycled by the portal circulation
  • Lipids
  • Electrolytes

References

1. Hall, JE, and Guyton AC. Guyton and Hall Textbook of Medical Physiology. 11th Edition. Philadelphia, PA: Saunders Elsevier. 2011.
2. Kam P, Power I. Principles of Physiology for the Anaesthetist. 3rd Ed. Hodder Education. 2012.