Fig. The plasma membranes of the epithelial cell (black arrow) and of the oligodendroglial process forming the myelin sheeth (inset, red arrow). The resolution of the three-layered membrane differs according to features of the embedding media (epithelium in polyester resinVestopal, nervous tissue in epoxy resin Durcupan). L - secondary lysosome. Scale = 200 nm. (Mouse, kidney tubule and cerebellar cortex). Download the high resolution image; Download the high resolution image (inset).