NERVOUS
NEUROGLIA
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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The action potential is produced by the sudden entry of NA ions into the cytoplasm.
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Propagation of the action potential along the microtubules of the axon constitutes the nerve impulse.
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Nervous impulse of a neuron does not originate in the initial segment of the axon, but in the dendrite.
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None of the above
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Detailed explanation-1: -Action potentials are caused when different ions cross the neuron membrane. A stimulus first causes sodium channels to open. Because there are many more sodium ions on the outside, and the inside of the neuron is negative relative to the outside, sodium ions rush into the neuron.
Detailed explanation-2: -If the cell body gets positive enough that it can trigger the voltage-gated sodium channels found in the axon, then the action potential will be sent. Depolarization-makes the cell less polar (membrane potential gets smaller as ions quickly begin to equalize the concentration gradients) .
Detailed explanation-3: -This starts with the opening of voltage-gated Na+ channels in the neuron membrane. Because the concentration of Na+ is higher outside the cell than inside the cell by a factor of 10, ions will rush into the cell, driven by both the chemical and electrical gradients.