formation
Last reviewed 01/2018
Bile first comes into existence after secretion into the biliary canaliculi of the liver; the formation of individual components within hepatocytes is considered in their respective subsection.
Bile salts largely determine the passage of other components into the canaliculi. They pass outwards from the hepatocyte by facilitated diffusion aided by a protein membrane carrier. It is proposed that phospholipids and cholesterol are packaged into vesicles by the hepatocyte; the vesicles then fuse with the membrane. Within the membrane, bile salts, phospholipid and cholesterol probably converge to form micelles before further transit.
Aside from this passage movement, bilirubin, ions, hormones and drugs pass from cell to canaliculus by the action of specific, active membrane transport.
With the accumulation of solute within the canaliculi, water follows by osmosis.
Bile is further modified during transit along the biliary tree and during storage in the liver.