The grey matter is the major component of the central nervous system. It consists of neurons bodies, dendrites, non-myelinated axons and myelinated axons, glial cells and capillaries. Grey matter contains neurons bodies, in contrast to white matter, which does not and mostly contains myelinated axon tracts. In living tissue, grey matter actually has a grey-brown color which comes from capillary blood vessels and neuronal cell bodies.
The grey matter is the cerebral cortex and the long H-like bundle found at the center of the spinal cord.