QUESTION 30 A neuron is more likely to undergo an action...

QUESTION 30 A neuron is more likely to undergo an action potential when A. voltage gated sodium channels have been pharmaceutically blocked and are closed B. the neuron is depolarizing and approaching the threshold voltage C. the neuron is hyperpolarizing D. the neuron is in a refractory period E. the neuron's potassium leak channels are the only open channels

Transcript

00:01 Okay, in order to answer this question, let's talk about the reaction potential.

00:04 Normally, your cell at rest is, it has high levels of potassium here and low levels of potassium in the extracellular.

00:12 And about the sodium levels, you have a lower levels on the inside of the cell, and you have higher levels of sodium outside.

00:20 Okay, this is what happens at the west.

00:22 And what about the voltage of your cell? well, your voltage of your cell or your neuron is like going to be approximately minus 70.

00:30 Milliboules.

00:31 This is the wasting memory potential.

00:34 Okay.

00:35 And what if there is a stimulus and this neuron wants to undergo an action potential? well, first, the voltage has to rise up to a value of minus 60 millivols that is a threshold potential.

00:46 This is a threshold potential.

00:48 If the voltage does not get to that threshold potential, then nothing is going to happen in action potential is not going to cure.

00:54 But if it gets to that threshold potential, then many voltage voltage, voltage, gated, sodium channels are going to open and there is going to be like a lot of influx of sodium ions inside of the cell.

01:14 It means down the concentration gradient because sodium is higher outside and lower inside.

01:18 So, sodium is going to get inside of a cell and this is going to guise the voltage of the cell like up to plus 30 milliboles because this sodium is positively charged.

01:30 So you're getting your pulling, you're pulling, you're going to, you're in positive charges.

01:34 So this is going to be going to make the voltage on the cell electropositive.

01:38 Now, at some moment, this voltage -gated solar channels are going to close and voltage -gated potassium channels are going to open.

01:46 And remember that potassium is higher here and lower here, so down the concentration gradient potassium is going to move in this direction...

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