The CNS has two kinds of tissue: grey matter and white matter, Grey matter, which has a pinkish-grey color in the living brain, contains the cell bodies, dendrites and axon terminals of neurons, so it is where all synapses are. White matter is made of axons connecting different parts of grey matter to each other.
The grey area in Figure 1 shows the location of grey matter in the middle of the
spinal cord and the white matter surrounding it.
The pink areas in Figure 2 show the grey matter of the cerebral cortex on the outer
surface of the cerebral hemispheres. The grey areas show grey matter inside the hemispheres and in
the front end of the brain stem.