Neuroscience: Action Potentials and Ionic Mechanisms Quiz

The repolarization phase follows the depolarization phase in the action potential (AP) of neurons.

The depolarization phase typically lasts less than 1 ms, while the repolarization phase lasts 1-2 ms.

A slight hyperpolarization beyond the resting membrane potential is common in many neurons.

A sudden increase in membrane permeability to Na+ and K+ ions causes the AP.

Depolarizing stimuli lead to opening of voltage-sensitive Na+ channels and Na+ influx, initiating the depolarization phase.

The influence of sodium (ENa+) is short-lived as membrane permeability to potassium (EK+) increases, allowing potassium to leave and restoring dominance of EK+.

The membrane potential at which inward Na+ current equals outward K+ current is called threshold (Vth).

When Na+ ions enter the cell unbalanced by K+ ions, net positive charge is deposited and more Na+ channels open in a regenerative cycle.

The decrease in Na+ current during the AP is due to the inactivation gate of Na+ channels shifting into an occluding position after the channel opens.

Cl- ions may have an effect on the AP since Cl- channels are open at the resting potential and during the AP, and ECl is at the resting membrane potential in many neurons.

The membrane can be modeled as an equivalent circuit with electromotive forces (EMF), resistances (R), and capacitance (C), illustrating passive membrane properties.

An action potential can be described as a transient decrease in resistance in the Na+ arm followed by a transient decrease in resistance of the K+ arm.

Threshold potential is not a fixed value and can be affected by factors such as changes in the magnitudes of inward Na+ and outward K+ currents.

Accommodation is a process where significant numbers of Na+ channels become inactivated, decreasing the neuron's sensitivity to depolarization and affecting the threshold potential.

The repolarization phase follows the depolarization phase in the action potential (AP) of neurons.

The depolarization phase typically lasts less than 1 ms, while the repolarization phase lasts 1-2 ms.

A slight hyperpolarization beyond the resting membrane potential is common in many neurons.

A sudden increase in membrane permeability to Na+ and K+ ions causes the AP.

Depolarizing stimuli lead to opening of voltage-sensitive Na+ channels and Na+ influx, initiating the depolarization phase.

The influence of sodium (ENa+) is short-lived as membrane permeability to potassium (EK+) increases, allowing potassium to leave and restoring dominance of EK+.

The membrane potential at which inward Na+ current equals outward K+ current is called threshold (Vth).

When Na+ ions enter the cell unbalanced by K+ ions, net positive charge is deposited and more Na+ channels open in a regenerative cycle.

The decrease in Na+ current during the AP is due to the inactivation gate of Na+ channels shifting into an occluding position after the channel opens.

Cl- ions may have an effect on the AP since Cl- channels are open at the resting potential and during the AP, and ECl is at the resting membrane potential in many neurons.

The membrane can be modeled as an equivalent circuit with electromotive forces (EMF), resistances (R), and capacitance (C), illustrating passive membrane properties.

An action potential can be described as a transient decrease in resistance in the Na+ arm followed by a transient decrease in resistance of the K+ arm.

Threshold potential is not a fixed value and can be affected by factors such as changes in the magnitudes of inward Na+ and outward K+ currents.

Accommodation is a process where significant numbers of Na+ channels become inactivated, decreasing the neuron's sensitivity to depolarization and affecting the threshold potential.