Lecture Notes: The Role of Bile in Digestion
What is Bile?
- Bile is a digestive juice.
- Production and Storage:
- Produced in the liver.
- Stored in the gallbladder.
Major Functions of Bile
- Involved in fat digestion and absorption in the intestinal tract.
- Emulsifies fat to aid in digestion.
Digestion Process
- Fat Ingestion:
- Fat does not dissolve in water.
- Requires a different digestion process compared to proteins or carbohydrates.
- Fat in the Digestive System:
- Fat clumps together and forms large fat droplets.
- When reaching the small intestine, bile is released.
- Role of Bile in the Small Intestine:
- Bile mixes with large fat droplets.
- Contains bile salts that emulsify fat, breaking it into smaller droplets.
- Action of Pancreatic Lipase:
- Breaks fat into free fatty acids and monoglycerides.
- These are small enough to pass through the epithelial cell layer of the villi.
Absorption
- Villi:
- Tiny finger-like projections on the interior of the small intestinal wall.
- Contain blood capillaries and lymph capillaries.
- Fat Absorption:
- Fats absorbed into lymph capillaries.
- Transported to liver via lymphatic duct and circulatory system.
Additional Roles of Bile
- Removal of Bilirubin:
- Bilirubin is a substance made when old blood cells are broken down.
- Cholesterol Removal:
- Some cholesterol is converted to bile acids and eliminated in feces.
Bile is essential for the digestion and absorption of fats and plays a role in removing certain substances from the body, demonstrating its critical function in maintaining digestive health.