Definition
- Bile secretion is the formation of bile by hepatocytes and its modification by bile duct and gall bladder epithelium, comprising bile acid-dependent canalicular flow and bicarbonate-rich ductular secretion.
Bile secretedabout 1 litre daily
Bile Salt Actions
- Bile salts are amphipathic and have a detergent action on lipids.
- Bile salts, together with lecithin, solubilize cholesterol in bile, preventing cholesterol precipitation and gallstone formation.
- Bile salts are themselves the most important choleretic: they stimulate further bile secretion.
Mechanism of Bile Secretion
- Canalicular flow: bile acids and the Na+-K+ ATPase of hepatocytes drive bile flow into the canaliculi.
- Ductular secretion: bile duct epithelial cells actively secrete a bicarbonate (HCO3−) and chloride (Cl−) rich fluid into the lumen.