Nerve fibre. Transmission electron micrograph (TEM) of a section through a sciatic nerve,showing a node of Ranvier and myelinated and unmyelinated nerve fibres (axons). Myelin (brown) is a fatty insulating sheath composed of schwann cells that surrounds the axon and increases the speed of the nerve signal. Nodes of Ranvier are areas of exposed axon,with a high concentration of sodium channels. Instead of travelling continuously along the length of the axon,the impulse jumps between these nodes in a process called saltatory conduction. This allows the impulse to travel over long distances. Magnification: x10,000 when printed 10 centimetres wide | |
Lizenzart: | Lizenzpflichtig |
Credit: | Science Photo Library / Gschmeissner, Steve |
Bildgröße: | 5120 px × 3418 px |
Modell-Rechte: | nicht erforderlich |
Restrictions: | - |