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Unformatted text preview: Transmission of Nerve Impulses The transmission of a nerve impulse along a neuron from one end to the other occurs as a result of electrical changes across the membrane of the neuron. The membrane of an unstimulated neuron is polarizedthat is, there is a difference in electrical charge between the outside and inside of the membrane. The inside is negative with respect to the outside. Polarization is established by maintaining an excess of sodium ions (Na + ) on the outside and an excess of potassium ions (K + ) on the inside. A certain amount of Na + and K + is always leaking across the membrane through leakage channels, but Na + /K + pumps in the membrane actively restore the ions to the appropriate side. The main contribution to the resting membrane potential (a polarized nerve) is the difference in permeability of the resting membrane to potassium ions versus sodium ions. The resting membrane permeability of the resting membrane to potassium ions versus sodium ions....
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- Spring '10