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A : Presence of myelin sheath increases the rate of conduction of nerve fibre B : Ionic channels are absent ib the area covered by myelin sheath therefore, depolarization occurs only at nodes of Ranvier, resulting in saltatory or jumping conduction. (See the image to answer)

A : Presence of myelin sheath increases the rate of conduction of nerve fibre
B : Ionic channels are absent ib the area covered by myelin sheath therefore, depolarization occurs only at nodes of Ranvier, resulting in saltatory or jumping conduction.
 
(See the image to answer)

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Grade:12th pass

1 Answers

Simran Vinaik
askIITians Faculty 1230 Points
4 years ago
There are gaps callednodes of Ranvierbetween the schwann cells which are the onlyplaces wheredepolarisationcanoccur(due to Na+ entering the cell). This means that thedepolarisationjumps from onenodeto the next every 0.5 milliseconds via saltatory conduction, whichincreasesthespeedof conduction.Both Assertion and reason are correct so mark 1.

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