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    Hi there, TSR

    I'm just wondering about all the different potentials in AQA unit 5.

    So what's the difference between action potential, generator potential and resting potential?

    I understand that action potential and resting potentials are related but how does generator potential fit into it?

    Many thanks.
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    A resting potential is found when a neurone is not sending a signal. The resting potential is polarised at -65 mv.

    A Action Potential is found when a node of Ranvier in a neurone is depolarised and is therefore sending a signal. Here the voltage across the membrane becomes +40 mv. This is how impulses are transmitted down a neurone. When this reverses it becomes hyper-polarised, which is called the refractory period, before it settles down again at a resting potential.

    A generator potential is what starts the chain of Action Potentials off, for example in the sensory cells of the eye. The changes in light energy cause the membranes there to change polarity , which produces a generator potential that starts a series of Action Potentials.
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    (Original post by Aillias)
    Hi there, TSR

    I'm just wondering about all the different potentials in AQA unit 5.

    So what's the difference between action potential, generator potential and resting potential?

    I understand that action potential and resting potentials are related but how does generator potential fit into it?

    Many thanks.
    As above. Note that the generator potential is not at the node of ranvier (as one may erroneously assume from the above post, which is otherwise very good), but it occurs at the dendrites (or the axon hillock).


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    (Original post by Tristian Fox)
    A resting potential is found when a neurone is not sending a signal. The resting potential is polarised at -65 mv.

    A Action Potential is found when a node of Ranvier in a neurone is depolarised and is therefore sending a signal. Here the voltage across the membrane becomes +40 mv. This is how impulses are transmitted down a neurone. When this reverses it becomes hyper-polarised, which is called the refractory period, before it settles down again at a resting potential.

    A generator potential is what starts the chain of Action Potentials off, for example in the sensory cells of the eye. The changes in light energy cause the membranes there to change polarity , which produces a generator potential that starts a series of Action Potentials.
    So essentially, an action potential is when the impulse gets going and the generator potential is when the action potential is being triggered.

    I'm just confused as to where action potential and generator potential occurs. So, action potentials only occurs at nodes of ranvier, and generator potentials only occurs at the receptor cells? But, how come, when neurotransmitters crosses the snyaptic cleft, my aqa textbook just says that this generates an action potential in the post synaptic neurone? Shouldn't it be it generates a generator potential, which then triggers an action potential? Or am i going into too much detail, detail, which i don't need to know for my exams?

    Sorry for any confusion, but my textbook is simply put, crap.
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    (Original post by Aillias)
    So essentially, an action potential is when the impulse gets going and the generator potential is when the action potential is being triggered.

    I'm just confused as to where action potential and generator potential occurs. So, action potentials only occurs at nodes of ranvier, and generator potentials only occurs at the receptor cells? But, how come, when neurotransmitters crosses the snyaptic cleft, my aqa textbook just says that this generates an action potential in the post synaptic neurone? Shouldn't it be it generates a generator potential, which then triggers an action potential? Or am i going into too much detail, detail, which i don't need to know for my exams?

    Sorry for any confusion, but my textbook is simply put, crap.
    Yes I think you are going into too much detail.

    Just know that the post synaptic membrane is itself a receptor, and that a generator potential is the stimulus just great enough to stimulate an action potential.
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    (Original post by byebyebadman)
    Yes I think you are going into too much detail.

    Just know that the post synaptic cleft is itself a receptor, and that a generator potential is the stimulus just great enough to stimulate an action potential.
    This may get confusing for OP, though, as the post synaptic membrane has receptors embedded into it.


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    (Original post by ash92:))
    This may get confusing for OP, though, as the post synaptic membrane has receptors embedded into it.


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    That's why I said the OP was probably getting into too much detail.

    All you need to know is that a generator potential is the requisite stimulus to activate an action potential in the post synaptic neuron.
 
 
 
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