Resting Membrane Potential and Action Potentials

Flashcards covering key concepts related to resting membrane potential and action potentials.

Resting Membrane Potential (RMP)

The voltage difference across the membrane of a cell at rest, typically around -70 mV in neurons.

Depolarization

A change in membrane potential that makes it more positive, typically occurring when sodium ions enter the cell.

Repolarization

The return of the membrane potential to resting levels after depolarization, usually involves potassium ions exiting the cell.

Hyperpolarization

An increase in membrane potential making it more negative than the resting membrane potential, often due to potassium ion efflux.

Action Potential

A rapid change in membrane potential that propagates along the axon, characterized by a peak of around +30 mV.

Threshold Potential

The critical level to which a membrane potential must be depolarized to initiate an action potential, typically around -55 mV.

Absolute Refractory Period

The period during which a second action potential cannot be initiated regardless of the strength of the stimulus.

Relative Refractory Period

The period following the absolute refractory period where a second action potential can occur only with a stronger stimulus.

Myelin Sheath

A fatty insulating layer around some axons that increases the speed of action potential propagation.

Voltage-Gated Channels

Protein channels that open or close in response to changes in membrane potential, crucial for action potential generation.

Tetrodotoxin (TTX)

A potent sodium channel blocker derived from pufferfish that prevents action potentials.

Tetraethylammonium (TEA)

A potassium channel blocker that results in prolonged action potentials by inhibiting repolarization.

Graded Potential

Small changes in membrane potential that do not reach the threshold for action potentials and can vary in magnitude.

Na+/K+ Pump

A pump that restores resting membrane potential by moving sodium ions out of the cell and potassium ions into the cell.

Neuron

The basic cellular unit of the nervous system that transmits signals; composed of dendrites, cell body, and axon.