Axon
Axons send impulses down their body. Impulses jump between exposed areas on the axon not covered by the myelin sheath called the nodes of Ranvier. The myelin sheath is made by glial cells. Axons are covered in spots in myelin sheath made by oligodendrocytes in the central nervous system (CNS), or Schwann cells in peripheral nervous system (PNS). Neurons are made up of two regions: the cell body and dendrites as one region and axonal body as another. The axonal region of neurons consists of the axon hillock which receives an action potential from the neuron which generates an action potential from the initial segment. The axonal initial segment (AIS) separates the main part of the axon from the rest of the neuron and also initiates action potentials. The AIS is unmyelinated and has a certain plasticity to it which allows for adaptability and the fast conduction of nerve impulses, which is achieved by a large concentration of voltage gated sodium channels in the initial segment where the action potential is initiated.