ABSTRACT
The central nervous system is made up of the brain and the spinal cord. The brain can be described as having three major parts: the brainstem, the cerebellum and the cerebral cortex. The brainstem is the lowest part of the brain, which tapers into the spinal cord. The cerebellum – meaning 'little brain' – is a cauliflower-like structure that sits under the cerebral cortex. The cerebral cortex is the largest part of the brain, dedicated to the highest levels of thinking, moving and acting, and makes up seven-tenths of the entire nervous system in humans. Brain tissue is made up primarily of nerve cells – or neurons – and supporting cells called glial – meaning glue – cells. Each cell also has a single thinner and potentially very long fibre called an axon, which transmits. The ends of axons do not actually touch dendrites, as there are minute gaps, called synapses, over which these chemical or electrical messages must travel.
