It is the largest part (about two third) of the human brain. It contains slightly more than half of the ten billion neurons of human nervous system. The cerebrum consists of two cerebral hemisphere joined by a curved thick band of nerve fibres, called corpus callosum. The outer layer of the cerebrum , known as cerebral cortex , is formed of grey matter and white matter. Physiologically the cerebral cortex is the highest level in the whole nervous system. Specific regions of cerebral cortex include the following areas: motor area (control voluntary movements), sensory are(heat, cold, pain, touch, light, pressure and muscle cells), auditory area, visual area, olfactory area(taste and smell) and speech area. The functions of the cerebral cortex are
Functions of Cerebrum
- All voluntary movements are controlled by the cerebrum.
- The motor areas in the frontal lobe of the brain transmit impulses which initiate activities in the muscles and glands.
- Association between various sensations and movements are controlled by association areas, in the frontal lobe.
- The area of the cerebral cortex to which the sensory signals are projected is called the somaesthetic cortex. In man, this area lies mainly in the parietal lobes. This area is the seat for perception of sensations like pain, touch and temperature.
- The visual area and auditory area, in the cerebral cortex is the centre of vision and hearing.