Scanning electron microscopy of the rat bile canalicular-ductular junction.

Scanning electron microscopy revealed two types of bile canalicular-ductular junctions in rats. 1. Several bile canaliculi converged to enter the terminal bile ductule by direct continuity, forming an ampulla just before the junction. The ampulla was about 2.5x6 micrometers, whereas the canalicular diameter was about 1.5 micrometer just before the ampulla and the ductular diameter was 1.2--4.0 micrometers. The ampulla was mainly walled by several hepatocytes and partly by a few ductular cells. The hepatocytes abutted on the bile ductular cells. 2. Bile canaliculi connected directly to the bile ductule as a side branch without forming the ampullary dilation. In this case, a part of the bile ductular canal was formed by the hepatocytes at the junction of the bile canaliculus with the bile ductule. This study confirmed the light microscopy observation of Lettule and McIndoe.