Osmosis video - Excitability and refractory periods

Excitability is the ability of a neuron to fire an action potential (spike of electricity). The refractory period is a period of time immediately following an action potential during which the neuron cannot fire another action potential. The refractory period is important because it favors unidirectional propagation of action potential along an axon, and limits the rate at which impulses can be generated.