15.3 passage of an action potential

Question 1

what is meant by saltatory conduction?

Answer 1

action potentials jump from node to node & only occurs at Node of Ranviers

Question 2

how is the myelin sheath used in a myelinated axon?

Answer 2

fatty sheath of myelin acts as an insulator & prevents action potentials from forming

Question 3

continuing from depolarisation of the axon membrane, how is an action potential passed in an unmyelinated axon?

Answer 3

3- influx of Na+ ions open Na+ voltage-gated channels further along the axon & causes depolarisation
4- behind the new region of depolarisation, Na+ voltage-gated channels close & K+ voltage-gated channels open
-> depolarisation moves along membrane