Organization of the Vascular Supply to the Brain of the Toad Bufo-Marinus

Abstract

The vasculature of the brain of the cane toad, Bufo marinus, was studied by means of scanning electron microscopy of vascular corrosion casts. The sole arterial supply to the brain is from branches of the internal carotids. The forebrain is supplied by several branches from the rostra1 ramus of the carotids; the caudal ramus gives rise to a single branch which supplies the mesencephalon and cerebellum. The caudal rami fuse to form a single basilar artery which supplies the medulla. The vascular supply to the choroid plexus of the third ventricle is arterial; the vascular supply to the choroid of the fourth ventricle is entirely venous. Microvascular geometry in the toad brain is specific to the region of the brain examined, ranging from simple long capillaries with few anastomotic connections to much shorter, highly convoluted capillaries with many anastomotic connections.