Why are gray matter and white matter contained in human nervous system named so ?

Gray matter consists of neuron cell bodies, dendrites, and unmyelinated axons. In the brain, it is located externally, while in the spinal cord it is internal. White matter consists of bundles of axons that ARE myelinated, giving it the whitish appearance for which it is named. In the brain, it is located internally, and in the spinal cord, it is external. (Opposite from gray matter). White matter is responsible for learning, emotions, processing sensory information, etc.