Action potential questions?

Posted on 2015-11-19 06:13:00 in Chemistry by MEKAY

Why does Na+ enter the cell during the action potential?

1. Because the Na+ channels are open and only let Na+ move from outside to inside.
2. Because the action potential pulls positive ions into the cell while Na+ and K+ channels are open.
3. Because Na+ channels are open and allow Na+ ions to move down the length of the axon to produce neurotransmitter at the axon terminal.
4. Because Na+ channels are open and there is a higher concentration of Na+ outside of the neuron than inside.

Which statement below is TRUE about the voltage-gated Na+ channels during the action potential?

1.The voltage-gated Na+ channels are open the entire time that the neuron is depolarized (when Vm is above resting potential).
2. The voltage-gated Na+ channels open after the voltage-gated K+ channels.
3. The voltage-gated Na+ channels open to restore Vm to the resting potential after the action potential peak.
4. The voltage-gated Na+ channels are open when Vm is rapidly increasing during the action potential.

What is the role of myelin in neurons?

1. To change the direction that Na+ and K+ move through ion channels during the action potential.
2. To increase the speed that action potentials travel down the neuron.
3. To prevent the neuron from generating action potentials.
4. To cause multiple sclerosis when present and intact, as it blocks action potential movement and must be removed by the immune system.

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