Neuron has three basic parts: the dendrites, the cell body, and the axons. some neurons have a fatty layer covering called around their axons. this layer isn’t continuous, and the gaps are called . the action potential jumps through these gaps to the transmission.

A neuron comprises three fundamental components, that is, the cell body, dendrites, and axons. Some of the neurons exhibit a fatty layer covering known as the Schwann cells enveloping their axons. This layer is not continuous, and the gaps are known as the nodes of Ranvier. The jumping of the action potential takes place via these gaps to elevate the speed of the transmission.  

The Schwann cells are the glial cells, which mainly offer myelin isolation from the axons of the vertebrate PNS. It prevails only at the PNS, while oligodendrocytes perform this function in the CNS, they form the myelin sheath surrounding a single axon.  

The gap between the two Schwann cells is known as the Ranvier's nodes. These nodes are the essential locations of ion exchange between the extracellular fluids and the axon. This alignment permits saltatory conduction of the high-speed action potential that provides speed at certain occasions of more than one hundred meters in a second, and at the same time saves energy as well.  

i think its control and coordinate because im pretty sure thats what tissue does and the joints are what control movement and then your skeletal/ bones provides portection. hope that .

friedrich meischer discovered it in white blood cell