The Vascularization of the Anuran Brain: The Choroid Plexus of the Fourth Ventricle

Abstract

AbstractThe angioarchitecture of the choroid plexus of the fourth ventricle of the toad, Bufo bufo (L.) has been studied by scanning electron microscopy of vascular corrosion casts. The results agree with the findings of Gaupp (1898) and show a wholly venous supply of the plexus. The drainage is exerted via venae choroideales rhombencephali. We discern three distinct but continuous zones. They are from dorsal to ventral a) the vascular reticulum within the tela choroidea, b) transverse orientated vascular nets within the ventricular folds (10–15) of the tela choroidea and c) vascular loops within the choroidal villi. — In the present paper we also discuss the method we used. Its advantages are powerful representation, striking information concerning the microvascular patterns and some hints to the statics caused by them, the possibility of tracing arteries through capillaries to veins over a long distance and the demonstration of vascular routes between important functional regions. Evasation, caused by to high injection pressures, no evidence for the direction of blood flow, no fully convincing surface patterns of the casts which clearly indicate arteries or veins (arterioles or venoles) and no reliable reflection of the physiological state of the animal are shortcomings, which demand a careful interpretation of the results.