Major Areas of the Brain

The human brain is part of the central nervous system (CNS). Three large regions are easy to identify on a side view of the brain: the cerebrum, the cerebellum and the medulla oblongata.The cerebrum is the largest part of the brain. It is divided into left and right cerebral hemispheres, joined by a band of nerve fibres called the corpus callosum. Its thin, highly folded outer layer, the cerebral cortex, is grey matter made of neurone cell bodies. The folding gives a large surface area for a great many neurones. The cerebrum controls conscious activities: thought, language, reasoning, memory, interpreting sensory information and starting voluntary movement. Each hemisphere mainly controls the opposite side of the body.The cortex is divided into four lobes. The frontal lobe is involved in planning, decision making and voluntary movement (it contains the motor cortex). The parietal lobe processes touch, temperature and pain. The occipital lobe contains the visual cortex. The temporal lobe processes sound and is involved in language and memory.The cerebellum lies at the back of the brain, below the cerebrum. It coordinates muscle movement, balance and posture, so that movements are smooth and accurate. It receives information from the eyes, the balance organs of the inner ear and stretch receptors in muscles.The medulla oblongata is at the base of the brain, where it joins the spinal cord. It controls automatic (non-conscious) functions, including the centres that regulate breathing rate and heart rate.