Bile is a fluid secreted from the liver and stored in the gall bladder. It is secreted into the small intestine where it helps in the digestion of fats/lipids.

Bile is a yellowish-greenish fluid secreted from the liver. It contains bile salts that help in the digestion of fats/lipids. After production in the liver, the bile is moved to the gall bladder where it is stored. Whenever food reaches the small intestine, the bile is secreted from the gall bladder to the small intestine. In the small intestine, bile helps to breakdown large fat/lipid molecules into smaller molecules by the process of emulsification. When exposed to water mixed with fat, such as in the small intestine, the bile salts congregate around a fat droplet with their hydrophobic side pointing towards the fat and their hydrophilic side pointing towards the water. This helps their digestion by lipase enzyme by increasing their surface area.

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Key Points

• Bile is secreted from the liver into the gall bladder from where it is secreted into the small intestine.

• The bile helps to emulsify the large fat molecules to smaller molecules so that they can be digested by lipase in the small intestine.

• Bile, which is alkaline, also has the function of neutralizing any excess stomach acid in the small intestine.

Key Terms

emulsification: breakdown of large fat molecules into smaller molecules

bile: a fluid produced by the liver to digest the fats in the small intestine.

bile salts: made of bile acids that are conjugated with glycine or taurine. They are produced in the liver, directly from cholesterol

liver: a large organ in the body that stores and metabolizes nutrients, destroys toxins, and produces bile. It is responsible for thousands of biochemical reactions.

lipase: enzymes in the pancreatic juices that break down lipids.

gall bladder: the small sac-shaped organ beneath the liver, in which bile is stored after secretion by the liver and before release into the intestine

hydrophobic: water-fearing, the molecule does not interact well with water

hydrophilic: water liking, the molecule interacts well with water