Microvascularization of the canine hepatic ducts

The angioarchitecture of the proximal and distal segments of the hepatic duct in the dog was investigated by means of vascular corrosion casts under a scanning electron microscope. The results of observations indicated a change of the pattern of vascularization of the hepatic duct along with the increasing distance of the hepatic duct from the liver and increasing diameter of the duct. In the proximal hepatic duct, the main blood vessels run along the duct as a pair of supplying arteriole and voluminous collecting venule, while in the distal segments of the hepatic duct on the opposite margin of the duct two vascular triads were observed, composed of two venules and one medial arteriole. On the surface of both segments of the hepatic duct, there are well-anastomosed outer venous plexuses. In the distal segments of the hepatic duct, the outer venous plexus accompanies a fine outer arterial rete. Observations of the intramural network indicate the presence of single terminal arterioles running to mucosa and supplying a subepithelial capillary network. Differences were observed in the blood drainage from the mucosa, as in the proximal segment of the hepatic duct single post-capillary venules are found, while in the distal segment in the mucosa a well-developed mucosal venous plexus is formed. In the well-developed venous system of the hepatic duct no valves were observed.