Nerve fibres. Coloured scanning electron micrograph (SEM) of myelinated nerve fibres (axons, purple) in a nerve cell (neurone). The neurone is composed of numerous fibres separated by layers of connective tissue (endoneurium, orange). The fibres carry electrical nerve impulses away from the neurone cell body, towards other nerve cells, the muscles or organs. Each fibre is surrounded by a fatty insulating layer known as a myelin sheath (pink in cross- section), which increases the transmission speed of the nerve signals. Nerves in the body serve to collect, interpret and relay information. Magnification unknown.