Fig. 3.11. Blood capillary with fenestrated endothelium and a wide perivascular space. They are typical in circumventricular organs. L - lumen, blue arrow - endothelial pore, red arrow - basal lamina, P - perivascular space, F - fibrocyte. Inset: blood capillary with the wide perivascular space. Scale = 200 nm. (Rat, area postrema.) Download the high resolution image; Download the high resolution image (inset).