7.2 Human Nutrition – The Alimentary Canal: Bile

This section focuses on the function of bile and its crucial role in fat digestion within the alimentary canal.

What is Bile?

Bile is a fluid produced by the liver and stored in the gallbladder.

Function of Bile

The primary function of bile is to aid in the digestion and absorption of fats.

Role in Fat Digestion

Fats are hydrophobic, meaning they do not mix with water. The digestive system relies on enzymes that require a watery environment to function effectively. Bile overcomes this challenge through a process called emulsification.

Emulsification: Bile salts, which are a key component of bile, have both hydrophobic and hydrophilic regions. The hydrophobic regions interact with the fat molecules, while the hydrophilic regions interact with the surrounding water. This process breaks down large fat globules into smaller droplets, increasing the surface area available for digestive enzymes (lipases) to act upon.

This increased surface area significantly enhances the efficiency of fat digestion by lipases. Lipases are enzymes that specifically break down triglycerides (the main component of fats) into glycerol and fatty acids.

Summary Table

Component	Function
Bile Salts	Emulsifies fats, breaking down large globules into smaller droplets.
Bile	Facilitates the absorption of fat-soluble vitamins (A, D, E, K).

Without bile, fat digestion would be much less efficient, leading to poor absorption of fats and fat-soluble vitamins.

Further Learning

Consider researching the composition of bile and the specific chemical nature of bile salts for a deeper understanding.