AP PSYCHOLOGY

Detailed explanation-1: -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: -They are the first channels to open in response to changes in voltage, allowing positively charged sodium ions to accumulate in the interior of the cell.

Detailed explanation-3: -Depolarization is caused by a rapid rise in membrane potential opening of sodium channels in the cellular membrane, resulting in a large influx of sodium ions. Membrane Repolarization results from rapid sodium channel inactivation as well as a large efflux of potassium ions resulting from activated potassium channels.

Detailed explanation-4: -Action potentials are caused when different ions cross the neuron membrane. A stimulus first causes sodium channels to open.

Detailed explanation-5: -Depolarization of the plasma membrane due to opening of gated Na+ channels. (a) Resting neurons non gated K+ channels are open, but the more numerous gated Na+ channels are closed. The movement of K+ ions outward establishes the inside-negative membrane potential characteristic of most cells.