Neurones. Coloured transmission electron micrograph (TEM) of a section through the cell bodies (purple), of neurones (nerve cells). The cell body is in the grey matter of the brain. Grey matter consists of supportive nerve cells called neuroglia, cell bodies and fine processes called dendrites and axons. Extending from the cell bodies are long, thin processes known as axons. The axon is responsible for carrying impulses (messages) away from the cell body, while dendrites carry impulses towards it. The surrounding material is the brain's grey matter. Magnification: x500 when printed at 10 centimetres wide.