Gallbladder

Definition

The gallbladder is a small, pear-shaped organ located beneath the liver that stores and concentrates bile, which is produced by the liver. Bile plays a critical role in the digestion and absorption of fats in the small intestine, aiding in the emulsification of lipids and facilitating their breakdown into absorbable molecules.

5 Must Know Facts For Your Next Test

1. The gallbladder can hold about 30-50 milliliters of bile, which becomes concentrated as it is stored, increasing its effectiveness in fat digestion.
2. When fatty foods enter the small intestine, the release of cholecystokinin triggers the gallbladder to contract and release bile into the duodenum.
3. The bile released from the gallbladder contains bile salts, cholesterol, bilirubin, and other substances that aid in lipid digestion and absorption.
4. If the gallbladder is removed (a procedure called cholecystectomy), bile flows directly from the liver to the small intestine, but digestion of fats may be less efficient.
5. Gallstones can form in the gallbladder due to imbalances in bile composition, leading to potential blockage and inflammation if not treated.

Review Questions

• How does the gallbladder's function relate to lipid digestion in the small intestine?
  • The gallbladder plays a crucial role in lipid digestion by storing and concentrating bile produced by the liver. When fatty foods enter the small intestine, hormones like cholecystokinin signal the gallbladder to release bile. This bile contains bile salts that emulsify fats, breaking them down into smaller droplets that lipase enzymes can act upon for effective absorption of fatty acids and glycerol.
• Discuss the hormonal regulation of bile release from the gallbladder during digestion.
  • The release of bile from the gallbladder is primarily regulated by the hormone cholecystokinin (CCK). When food, particularly fats, enters the small intestine, CCK is secreted into the bloodstream. This hormone stimulates the gallbladder to contract and release concentrated bile into the duodenum, facilitating lipid digestion. Other hormones like secretin also play a role by promoting bile production in the liver.
• Evaluate the implications of gallbladder removal on lipid digestion and absorption.
  • Removing the gallbladder can significantly affect lipid digestion because it disrupts the storage and concentrated release of bile. While bile continues to be produced by the liver, it flows directly into the small intestine without being concentrated. This leads to less efficient emulsification of dietary fats, often resulting in poor fat absorption and digestive issues such as diarrhea or steatorrhea. Individuals may need to adjust their diets to manage these changes effectively.

Related terms

Bile: A digestive fluid produced by the liver that helps emulsify fats and aids in their absorption in the small intestine.

Cholecystokinin (CCK): A hormone released by the small intestine in response to food intake, stimulating the gallbladder to contract and release bile into the digestive tract.

Lipase: An enzyme that breaks down dietary fats into fatty acids and glycerol, working alongside bile to facilitate lipid digestion.