Question

Why does the outer part of the cerebrum appear grey & whereas the inner part appears white?

Answer 1

Hint: The cerebrum is the uppermost part of the brain which contains two hemispheres split by a falx cerebri of dura mater.
Grey matter contains the cell bodies, dendrites, and axon terminals of neurons so have synapses. White matter is made of axons connecting different parts of grey matter to each other.

Complete answer: Grey matter is mostly found on the brain's outer surface, or cortex. White matter is buried deep in the brain.
1. Grey matter is mostly neuron cell bodies and non-neuron brain cells called glial cells.
These glial cells provide nutrients and energy to neurons.
2. Grey matter helps transport glucose into the brain, clean the brain of excess chemicals, and may even affect the intensity of the neurons' communications.
3. These cells are not surrounded by white myelin, so they take on the natural grayish color of the neurons and glial cells. In a living person, it actually looks pinkish-brown, because it has so many tiny blood vessels called capillaries
4. The white matter of the brain is made up primarily of axon tracts, the long, spindly appendages of some brain cells. These tracts transmit the electrical signals that the brain cells, called neurons, use to communicate.
5. They're wrapped in a fatty layer called myelin, which insulates the axons and allows them to conduct signals quickly.

Note: The spinal cord, which transmits nerve impulses to and from the rest of the body, has the opposite arrangement. It has grey matter at its core with the insulating white matter on the outside.