This medium magnification EM shows a portion of a neuron cell body, with a large nucleus and a portion of two glial cells (an astrocyte and an oligodendrocyte) with smaller nuclei. To the right, the image is filled with axons and dendrites with little or no intercellular space. This arrangement is characteristic of the central nervous system (CNS). The darkly stained membranes are those of myelinated axons. Small structures within the axons and dendrites are mitochondria.