What would probably happen if a long neuron had one continuous myelin sheath down the length of the axon with no nodes of Ranvie
r? A. The action potential would be propagated nearly instantaneously to the synapse. B. There could be no action potential generated at the axon hillock. C. The signal would fade because it is not renewed by the opening of more sodium channels. D. Only potassium could move across the membrane, but not sodium.
The signal would fade because it is not renewed by the opening of more sodium channels
Myelin sheaths protect nerve axons from damage. These sheaths are a lipid-rich stretch of the plasma membrane formed in the peripheral nervous system (PNS) by Cell bodies and in the central nervous system by oligodendrocytes (CNS). The myelin sheath is periodically broken all along length of the axon by specific areas known as nodes of Ranvier, which are needed for action potential propagation along the axon. The Ranvier nodes are critical in the speed and timing of impulse transport from one neuron to another, and variations in size or activity have the potential to compromise a neuron's efficacy, resulting in the emergence of neurological diseases.
