Fig. 3.07. The wall of the venule. L - lumen, E - endothelium, M - smooth muscle cell, C - collagen fibres in the perivascular space of Virchow-Robin. Inset: collagen fibres cut transversally and longitudinally. Scale = 2 µm. (Rabbit, neocortex.) Download the high resolution image; Download the high resolution image (inset).