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    hi guys, just wondering if someone can explain to me why an increased diamater increases the speed of conduction in a neurone? i understand why myelin helps increase the speed (action potential jumps from node to node instead of having to go down the whole axon), but how does diameter help?

    also, when they say diameter does it mean this:

    the diameter down the length of the axon

    dendrites<------------------------> synapse

    OR

    the diameter/width of the axon
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    Hey,

    Large diameter axons have low internal resistance while the greater the number of open channels in the membrane, the lower the membrane resistance. High internal resistance and low membrane resistance will result in slow propagation of the action potential.

    A commonly used analogy for the spread of these local currents is a leaky garden hose. Water pushing down the hose follows the path of least resistance; thus, if the diameter is narrow and there are many holes, water leaks out limiting the distance it can travel down the core of the hose. There are two solutions to getting water further down the hose. Either, increase the diameter of the hose thereby making the core a lower resistance pathway, or patch up the holes in the hose with tape thereby preventing leakage.

    Hope that helps
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    (Original post by snake2010)
    Hey,

    Large diameter axons have low internal resistance while the greater the number of open channels in the membrane, the lower the membrane resistance. High internal resistance and low membrane resistance will result in slow propagation of the action potential.

    A commonly used analogy for the spread of these local currents is a leaky garden hose. Water pushing down the hose follows the path of least resistance; thus, if the diameter is narrow and there are many holes, water leaks out limiting the distance it can travel down the core of the hose. There are two solutions to getting water further down the hose. Either, increase the diameter of the hose thereby making the core a lower resistance pathway, or patch up the holes in the hose with tape thereby preventing leakage.

    Hope that helps
    thanks a lot. so an axon with a low internal resistance and a high membrane resistance is the most desirable axon for the purpose of increasing speed of conduction?
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    the diameter/width of the axon

    is correct.
 
 
 
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