Source: Neuron; Creative Commons: http://commons.wikimedia.org/wiki/File:Neuron0.jpg Knee-jerk Reflex; Creative Commons: http://en.wikipedia.org/wiki/File:Patellar-knee-reflex.png
An automatic movement of the body that occurs as a response to stimuli.
The glial cells that compose the myelin sheath in the peripheral nervous system.
An insulating layer that surrounds axons neurons in the CNS and PNS and allows action potentials to propagate more quickly.
A nerve is a bundle of axons of neurons.