Question

ant Score: 10% Resources C Give Up? O Hint Check Answer of 10 Use the Action Potential Transmission tab of the Membrane Potentials interactive to help you answer the question. What would happen to the action potential transmission if voltage-gated sodium (Na+) channels in the initial axon segment were abnormally far apart from one another? The action potential would propagate more quickly than normal because saltatory conduction enables the depolarization signal to jump between voltage-gated Na+ channels. The action potential would propagate at a normal rate because only the concentration of neurotransmitter, not channel density, affects the strength of the depolarization signal. The action potential would not propagate at all because the depolarization signal dissipates before the closest voltage-gated Na* channels reach threshold. The action potential would propagate more slowly than normal because the weaker depolarization signal causes voltage-gated Nachannels to only open intermittently.

Answer 1

Option c is the right answer, no action potential will propagal because depolarization signal will disappiate before it reach to voltage gated Na channel.

Explanation-

The axon initial segment (AIS) is the site of initiation of action potential, located at the proximal axon. This part has high density of various ion channels ( Na, K and Ca etc ) . voltage-gated Na+ channels present about 5 to 50 fold higher in axon inital segment than in the distal part of axon or dendrites. This lowers the threshold membrane potential required for action potential initiation . If these channels located far from each other then threshold membrane potential required for generation of action potential will increase. And due to far located channels this threshold would not be achieved and no action potential.