Membrane Potentials and Action Potentials

These flashcards cover key vocabulary related to membrane potentials and action potentials important for understanding cellular excitability in biological systems.

Membrane Potential

The uneven ion distribution across the plasma membrane that creates an electrical gradient.

Resting Membrane Potential

Difference in charges across the membrane in an unstimulated or undisturbed cell.

Cytoplasmic Side

The side of the plasma membrane that is slightly negative compared to the extracellular side.

Concentration Gradient

Difference in ion concentrations across the membrane that affects the flow of ions.

Electrical Gradient

Difference in electrical charge across the plasma membrane affecting ion movement.

Depolarization

Membrane potential becomes less negative (more positive).

Hyperpolarization

Membrane potential becomes more negative.

Action Potential

The rapid rise and fall of the membrane potential resulting from the opening and closing of ion channels.

Ligand-Gated Channels

Channels that open in response to the binding of a specific molecule (ligand).

Voltage-Gated Channels

Channels that open or close in response to changes in membrane potential.

Na+/K+ Pump

Active transport mechanism that moves sodium ions out of the cell and potassium ions into the cell.

Mechanically-Gated Channels

Channels that open or close in response to stretching or pulling forces.

Negatively Charged Molecules

Large molecules inside the cell that exert attractive force on cations.

Skeletal Muscle Cell

Cell type with a typical resting membrane potential of about -85 mV.