00:01
How do we get an action potential? is it when, a, a neuron that reaches threshold potential, b, gated sodium channels close, c, sodium potassium pumps stop working, or d, gated potassium channels open? so an action potential, we have a resting membrane potential, which is negative, then we get a change to that potential, then we get depolarization, and then afterwards we get repolarization.
00:30
Remember this is all or nothing.
00:33
We either get an action potential or we don't.
00:36
Then this is based on threshold potential.
00:39
If there is a disturbance to membrane potential, but it doesn't reach the threshold, then there won't be an action potential.
00:46
If it does reach with threshold, then it's a positive feedback loop and we get fall depolarisation.
00:53
So what happens if we do reach with threshold potential? do we get closure of gated sodium channels? no.
01:00
We get a positive feedback loop and we get opening of them.
01:01
That's how we get the depolarization...