9.2.6 The Liver: Bile & Lipase

• Lipase


  Enzyme produced by the pancreas that breaks down lipids into fatty acids and glycerol
• Lipids


  • Large, insoluble molecules
  • Fatty acids and glycerol are smaller, soluble molecules that can be absorbed by the small intestine into the bloodstream
• Bile


  Alkaline substance made by the liver, stored in the gallbladder and released into the small intestine at the duodenum
• Functions of bile


  • Neutralizes stomach acid to make an optimum pH for the enzymes in the small intestine
  • Emulsifies lipids from larger fat globules to smaller lipid droplets, increasing the surface area to help lipase break down the lipids into fatty acids and glycerol much faster
• Bile does not break down lipids into fatty acids and glycerol, it just breaks them into smaller fat droplets
• Other roles of the liver

  • Deamination - Removal of the nitrogenous part of excess amino acids to make urea, which is toxic and is excreted in urine
  • Alcohol detoxification - The breakdown of alcohol
  • Breakdown of hormones - Hormones travel around the body in the blood and are broken down by the liver
  • Glycogen storage - Glucose molecules join together to make glycogen, which is broken down when glucagon (a hormone) is released when blood glucose concentration decreases