jalegris at xympatico.ca
Fri Nov 21 09:44:21 EST 2003
r norman wrote:
> The orginal post, snipped away for being non-sensical, did refer to
> the nervous system as supplying "electricity" to the body. However
> silly that notion was, it is still true that electricity involves far
> more than the movement of electrons -- that is how electric current is
> manifested in metallic conductors. Bioelectricity was known since
> Galvani's time.
> Electrical forces are at work between any two charged bodies. The
> energetics of ions moving across a membrane depend on their charge and
> the electrical potential, the voltage, as much as they do on
> concentrations and diffusion. The longitudinal flow of ions down
> axons is almost entirely a response to electrical forces.
> Yes, the real, physical, measurable electric currents that flow during
> nerve activity are "electricity".
Longitudinal flow of ions?? There are fast and slow tranport systems for
moving proteins, vesicles, and other chemicals down (and up) the axon,
but if you are talking about action potentials, the net movement of ions
is perpendicular to the axon, not along it. The action potential is the
only thing that "flows" along the axon in that sense, and it is a wave
of depolarization and associated electrical fields, not an ionic
current. If there was a longitudinal flow of ions down the axon there
would have to be a mechanism for supplying them at one end and for
getting rid of them at the other. No such mechanism exists to my knowledge.
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