It has control over the involuntary processes, such as growth, nutrition, etc.
The Cerebro-Spinal System attends to all the seeing, hearing, tasting, smelling, feeling, etc.

It sets things in motion; it is used by the Ego to think--to manifest consciousness.

It is the instrument with which the Ego communicates with the outside world.

This system may be likened to a telephone system, with the brain as the central office, and the spinal column and nerves as cable and wires respectively.
The brain is a great mass of nerve tissue, and consists of three parts, viz., the Cerebrum or brain proper, which occupies the upper, front, middle and back portion of the skull; the Cerebellum, or "little brain," which fills the lower and back portion of the skull; and the Medulla Oblongata, which Is the broadened commencement of the spinal cord, lying before and in front of the Cerebellum.
The Cerebrum is the organ of that part of the mind which manifests itself in intellectual action.

The Cerebellum regulates the movements of the voluntary muscles.