Oligodendrocyte. Coloured Scanning Electron Micro- graph (SEM) of an oligodendrocyte cell. This cell forms the myelin sheaths (concentric layers of membrane) around nerve fibres in the central nervous system. The myelin provides nutrients, structural support and insulation, allowing axons to conduct impulses more quickly. The branching processes connect the cell body to the myelin sheaths. One oligodendrocyte may be responsible for the myelination of up to 50 nerve fibres. Oligodendrocytes are destroyed in the disease Multiple sclerosis, causing demyelination of the nerves. Symptoms include vision & speech defects, and paralysis. Magnification: x965 at 5x7cm size.