00:01
So in this question, we're going to be looking at an action potential and a change in an action potential and trying to figure out the cause of that change.
00:08
So first, i'm going to draw a rough sketch of what the normal action potential looks like, something like that.
00:15
And then i will draw the one that changes a little bit, which is just a change in this area right here.
00:22
Ok, so to first understand how this change came to be, let's first talk about what each of these phases of the action potential mean.
00:29
Me.
00:30
So and i should have drawn this area here coming a little bit more out here because what this here is called the resting potential or the resting phase.
00:40
So here's where the cell membrane is polarized meaning that there's a voltage difference across it.
00:45
The inside of the cell is negatively charged compared to the outside of the cell and this happens around negative 70 millivolts.
00:53
This increase right here is called depolarization and this is when a stimulus triggers the opening of voltage -gated sodium channels which rush into the cell making the interior more positive and this depolarizes the membrane which increases our potential to reach about plus 30 millivolts here and i'll write minus 70 millivolts here okay and then now this area is what we'd call repolarization okay so after reaching its peak the sodium channels will close and voltage -gated potassium channels open potassium ions move out of the cell which restores our negative charge, again making the membrane potential more negative...