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    How come the natural resting potential of nerves in the human bodies is a negative value (usually -70mV)? Surely, it would be more stable to have the resting potential as 0V? Nerve impulses and action potentials could still be generated in a similar way so how come we start with negative potentials?
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    Perhaps because if our nerves are able to rest we die?

    (Original post by Hoofbeat)
    How come the natural resting potential of nerves in the human bodies is a negative value (usually -70mV)? Surely, it would be more stable to have the resting potential as 0V? Nerve impulses and action potentials could still be generated in a similar way so how come we start with negative potentials?
    Hi
    I am not an expert on neurones, but this is from my understanding

    (The negative value is possible because energy is continually being expended in the Na+/K+ pump - if you removed the source of ATP eventually the resting potential would vanish and it would just be 0V like you say - but I think you know that already )

    If you had it as 0V, how would you have the action potentials actually working? Like, when you opened the voltage-gated channels...if you had no potential difference and no chemical gradient.........nothing would happen, wouldnt it? (if you have thought of a way round this Id like to hear it )

    Rosie
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    (Original post by crana)
    Hi
    I am not an expert on neurones, but this is from my understanding

    (The negative value is possible because energy is continually being expended in the Na+/K+ pump - if you removed the source of ATP eventually the resting potential would vanish and it would just be 0V like you say - but I think you know that already )

    If you had it as 0V, how would you have the action potentials actually working? Like, when you opened the voltage-gated channels...if you had no potential difference and no chemical gradient.........nothing would happen, wouldnt it? (if you have thought of a way round this Id like to hear it )

    Rosie
    yep, i can c where u arrive at...just ....y it is -ve, not +ve??? i know i'm terrible....
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    For nerve impulses to be transmitted charges need to move and in order for them to move there must be a potential difference.

    (Charge would not flow around an electrical circuit if there wasn't a difference in potential.)
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    (Original post by Hoofbeat)
    How come the natural resting potential of nerves in the human bodies is a negative value (usually -70mV)? Surely, it would be more stable to have the resting potential as 0V? Nerve impulses and action potentials could still be generated in a similar way so how come we start with negative potentials?
    A nerve pulse travels in a very specific way. Nerve cells have, while resting an electric potential across their membrane. When they are stimulated by an electric impulse, receptors in the membrane opens allowing ions to pass through and cancel out the difference in electric potential. This sudden change of electric potential is detected by a nearby nervecell and so the process is reapeated. Because it takes longer time to build up this difference in electric potential, than it takes to open the gates and cancel it out, nerve cells keep the voltage across teh membrane high until a signal is received, and so a sudden pulse can travel very quickly through the nerve.
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    (Original post by Toto)
    yep, i can c where u arrive at...just ....y it is -ve, not +ve??? i know i'm terrible....
    Its a matter of definition. You can try it with a voltmeter and a battery. Take a normal 1,5V cell and measure the potential across it. Depending on how you connect it to the voltmeter you get either +1.5V or -1.5V. This is because electric potential is a difference. The electric potential at a point can only be defiend as compared to some 0. If you chose the negative end to be 0 then then the positive has a 1.5V greater electric potential thus +1.5V. However, if you define 0 to be at the positive end then the negative end has a voltage which is 1.5V less than this, thus -1.5V. Sometimes, one defines 0 to be at infinity. This often simplifies mathematical analysis, but the electric potential is still measured between two points, even if one of these points happens to be far away. Thus it is meaningless to say that a wire carries an electric potential of 10 000V. The propper statement would be that the electric potential between the earth and the wire is 10 000V.
 
 
 

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