Casts of hepatic blood vessels: a comparison of the microcirculation of the penguin, Pygoscelis adeliae, with some common laboratory animals.

Latex casts of the hepatic blood vessels of the penguin, Pygoscelis adeliae, and of some common laboratory animals were compared. There was general similarity between the different species, but the portal venous and hepatic arterial systems of the penguin were simpler than those of other species. Measurements were made of the volume and length of portal veins and it appears that the portal venous system is capable of being a more efficient blood reservoir in the penguin than in other species studied. The peribiliary plexus was especially well formed in the penguin and was drained by long veins which usually joined portal venous branches. Some of the long veins drained directly into the hepatic venous tree: these translobular veins were more prominent than in mammals. Anastomoses between hepatic artery and portal vein were not present in penguins, and the supply to the sinusoids appeared to be separate. The morphology of small hepatic veins of all the species appeared to be similar.