Fig. The myelin sheath terminates by widened rims of myelin loops and the ensheathed axon (A) becames naked in the region of the node of Ranvier (R). Note intercellular septate-like dark strips between oligodendroglial and axonal plasma membranes in the inset. Scale = 500 nm. (Rat, thalamic ventrobasal nucleus.) Download the high resolution image; Download the high resolution image (inset).