I don't understand this definition of "action potential" (1 Viewer)

[peppermint_stix]

okay this is regarding the "threshold" dot point..i have the definition of it, but when i was reading through the section on why not all stimuli generate an action potential, i had trouble understanding/relating this to the dotpoint.

"each stimulus produces either a full action potential or none at all. Each action potential is a separate event. Therefore, a cell cannot produce another action potential until the previous one is complete"

 

[babydoll_]

OK, well for example.
If I jabbed your leg with a pin, you would either:
a/ feel pain (full action potential for pain), OR
b/ feel nothing (none at all).

The cells receiving the pain, would not be able to feel more pain, until the previous pain is removed (completed). Does that make sense?

 

[jesshika]

why wouldn't the you feel nothing at all ??




Some stimuli don't create an action potential because
(a) the stimulus doesn't reach the level required to initiate a nervous impluse i.e. the threshold which is about -69mV
(b) the cell is still depolarized (positive charged outside) and for the neuron to conduct the next stimuli it needs to be repolarized ...
hope that helpsss

 

[bobbie212]

action potential is the potential difference across the plasma membrane of a neuron needed to generate a nerve impulse. so msg;s can be transported around the body

 

[iambored]

okay this is regarding the "threshold" dot point..i have the definition of it, but when i was reading through the section on why not all stimuli generate an action potential, i had trouble understanding/relating this to the dotpoint.

"each stimulus produces either a full action potential or none at all. Each action potential is a separate event. Therefore, a cell cannot produce another action potential until the previous one is complete"

ok well threshold must be met for the nerve to fire action potential. therefore the nerve must get enough stimulus, which means it will reach threshold and fire action potential.

when the cell fires, it's called the "all or none law" - so it either fires, or doesn't fire. it can't half fire, or three quarters fire (considering this, if, for example, pain is weaker, it doesn't mean it's half-firing, it means the rate of firing is lower. if it's stronger, the rate of firing is faster and there is more firing.)

when the cell fires, there is like a refractory period, or something like that, and during that time the cell cannot fire again - it needs some time to recover before firing again