Biology · Neurobiology

The explanations for increased conduction velocity of action potentials in a myelinated nerve fibre (MNF) as compared to that of a non-myelinated fibre (NNF) of the same diameter are suggested below: A. Much higher number of ions traverse a unit length of an MNF membrane compared to that of an NNF during conduction of action potential. B. The energy expenditure required to maintain ionic gradients after conduction of action potential in an MNF is higher than that of an NNF. C. The action potentials of MNF exhibit saltatory conduction where depolarization hops from node to node. D. The relative refractory period is not significantly extended in an MNF compared to an NNF. E. The axolemma at the internodes under the myelin sheath lacks active voltage-gated Na+ and K+ channels. F. MNFs are metabolically less efficient than NNFs. Choose the option containing statements that accurately describe the features of MNF vs NNF: