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<\/a>Axons can be either covered by myelin (myelinated<\/strong>) or bare (unmyelinated<\/strong>). Myelin is found in both the CNS and PNS; however, its composition and means of production are different. <\/p>\n\n\n\n Myelin sheaths are not continuous. They contain gaps which are called nodes of Ranvier<\/strong> (seen above)<\/p>\n\n\n\n Both in the PNS and CNS, myelin is produced by special supporting cells belonging to the family of neuroglial cells<\/strong>.<\/p>\n\n\n\n We’ll cover the myelination process and differences in each of the neuroglial articles.<\/p>\n\n\n<\/span>\n Nerve conduction can be either continuous<\/strong> (river-like flow of action potential across the cell membrane), as the classical type we’ve all been taught in high-school biology, or saltatory<\/strong> (“jumping”) conduction.<\/p>\n\n\n<\/span>\n In axons containing myelin sheaths, the action potential only occurs in the nodes of Ranvier — where the axon membrane is exposed.<\/p>\n\n\n\n This is preferable impulse conduction, since the signal travels much faster, because the action potential only happens in segments, without having to depolarize and repolarize the entire cell membrane.<\/p>\n\n\n\nMyelin in the PNS and CNS<\/h3>\n<\/span>\n\n\n
Conduction<\/h3>\n<\/span>\n\n\n
Saltatory conduction<\/h4>\n<\/span>\n\n\n