[Anatomical characteristics of the veins of the midbrain in vertebrates].

The venous bed has been studied in brain preparations of some Vertebrata (fishes, amphibia, reptiles, birds) with injection of the vessels. It has been noted that together with the morphological regularity in the structure of the midbrain portions, certain structural principles of its blood bed are kept. The venous outflow reflects the intermediate position of the midbrain: some blood in the animals studied flows from the midbrain into the basilar vein system, another portion of the blood flows into a tributary of the future central vein. Anatomical peculiarities of the midbrain veins in the animals studied demonstrate that it is the functional activity that determines the circulation in this part of the brain.