Function of Bile (WJEC GCSE Biology)

Function of Bile

• Bile is an alkaline substance produced by cells in the liver

• Before being released into the small intestine, bile is stored in the gall bladder

• Bile travels from the liver and gall bladder to the small intestine via a small tube called the bile duct

Organs that are involved in bile production and secretion diagram

Bile is produced in the liver and stored in the gall bladder

• Bile has two main roles:

  1. Neutralising the hydrochloric acid from the stomach

     • The alkaline properties of bile allow for this to occur

     • This neutralisation is essential as enzymes in the small intestine have a higher (more alkaline) optimum pH than those in the stomach

  2. Breaking apart large drops of fat into smaller ones (and so increasing their surface area)

     • This is known as emulsification

• The more alkaline conditions and larger surface area allows the lipase enzymes to chemically break down the fat (lipid) molecules into glycerol and fatty acids at a faster rate

The process of emulsification diagram

Bile breaks large fat droplets into smaller ones with a larger surface area