t the peak of the action potential, which is greater, inward current or outward

[evomase]

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At the peak of the action potential, which is greater, inward current or outward current?

 

[PingPongPro]

Leading up to the peak of an action potential, the inward current of Na+ has the greatest effect. After it reaches the peak, Na+ channels close, and K+ open, and potassium flows out.

 

[evomase]

What about at the peak of the action potential? Is the current greater inward or outward?

 

[PingPongPro]

Well... that's kind of a bad question because the peak is the exact point when the Na+ channels are closing and K+ channels are opening. At the exact peak of an action potential there wouldn't be any current because the flow in and out would be equal. A positive slope indicates that the Na+ ions are flowing in and the negative slope indicates the K+ is moving out. At the exact peak, the slope would be 0 because there is no net in/out. Remember the change in potential is due to the change in ion concentration (intracellular/extracellular).

Like throwing a ball straight up in the air, the exact moment that ball is at its apex, there is no net velocity.

 

[evomase]

that does make a lot of sense. thank you so much!