Ion Movement

K⁺

Ion with high concentration in a neuron at rest (20:1) and an equilibrium potential of -75 mV

Na⁺

Ion with low concentration in a neuron at rest (1:10) and an equilibrium potential of 65 mV

Cl^-

Ion with low concentration in a neuron at rest (1:12)

Organic anions

Ion only present inside in a neuron at rest (1:0)

Open ion channels

Ion channels open at all times

Open K⁺ channels

Open channels with a large number in neurons

Open Na⁺ channels

Open channels with a very small number in neurons

Voltage-gated ion channels

Channels that open or close at a specific membrane potential

Voltage-gated Na⁺ channels

Ion channels that open at a membrane potential of -55 mV

Voltage-gated K⁺ channels

Ion channels that open as the membrane potential increases

Ligand-gated ion channels

Ion channels that open when a specific chemical binds to it

Mechanical ion channels

Ion channels that open from physical force

Sodium-Potassium pump

Exchange of 2 Na+ ions for 3 K+ in the neuron using an ATP molecule

Membrane potential

Intracellular charge minus the extracellular charge of a neuron

Equilibrium potential

Balanced electrochemical gradient resulting in no net movement of a single ion

Resting potential

Membrane potential of -65 to -70 mV

Action potential

Neuron depolarization

Depolarization

Membrane potential increasing

Repolarization

Membrane potential decreasing

Hyperpolarization

Membrane potential decreasing to below the resting potential