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 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.
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.