[In a wire and in a nerve, charge moves. But in a wire, the wave – OK, we’re thinking waves here – moves like a bee flying in a squiggly line. The bee is actually moving. In a nerve, however, the wave is more like people doing the wave in a stadium. The wave moves, but no one has to get out of their seat. However, it has to be more like the flying bee for magnets to enter the picture.]
Beth-- your explanation of the transmission of impulses through a nerve cell was fascinating… but the above description falls short of clarifying things for me. If energy is moving through a medium, there is by definition a wave. Is the bee in the wire a wave, or an electron? 'cuz one moves, the other doesn’t.
In an alternating current, electrons are alternately pushed and pulled within the wire. The flowing charge is a wave, analogous to an acoustic wave, or a P-wave. As with all waves, there is no net transfer of matter (electrons, in this case).
A changing electric field (whether a direct current or an alternating current) will generate a magnetic field, and a magnetic field will change an electric field. The bees don’t have to move, just the charge. In your description of a nerve cell, a pulse is moved from one end of the cell to the other, creating a changing electric field and, therefore, a magnetic field.
How the cell is affected by an external magnetic field is much more complex however, since the cell is not a simple copper wire with free valence electrons. My point is not to disagree with you about the susceptibility of nerve impulses to external magnetic fields, therefore, but to clarify the difference between moving charge, moving electrons, and moving waves…