Membrane Potentials and Action Potentials

Vocabulary flashcards about membrane and action potentials.

Membrane Potential

Electrical potential difference across a cell membrane.

Diffusion Potential

Potential difference that develops across a membrane due to diffusion of ions.

Nernst Potential

The diffusion potential across a membrane that exactly opposes the net diffusion of a particular ion through the membrane.

Goldman Equation

An equation used to calculate the diffusion potential when the membrane is permeable to several different ions.

Resting Membrane Potential

The membrane potential of a cell in a quiescent or non-excited state.

Electrochemical Driving Force

The force that tends to cause movement of an ion across the membrane, determined by the difference between the membrane potential and the equilibrium potential of the ion.

Sodium-Potassium Pump

An active transport mechanism that pumps sodium ions out of the cell and potassium ions into the cell.

Action Potential

Rapid changes in the membrane potential that spread rapidly along the nerve fiber membrane.

Depolarization

The process by which the membrane potential becomes less negative.

Repolarization

The process by which the membrane potential returns to its resting state.

Voltage-Gated Sodium Channel

A sodium channel that opens or closes in response to changes in the membrane potential.

Voltage-Gated Potassium Channel

A potassium channel that opens or closes in response to changes in the membrane potential.

Activation Gate

The gate near the outside of the voltage-gated sodium channel that is closed in the normal resting membrane.

Inactivation Gate

The gate near the inside of the voltage-gated sodium channel that closes a few 10,000ths of a second after the activation gate opens.

Voltage Clamp Method

A method used to measure the flow of ions through specific channels by controlling the membrane potential.

Membrane Potential

Electrical potential difference across a cell membrane.

Diffusion Potential

Potential difference that develops across a membrane due to diffusion of ions.

Nernst Potential

The diffusion potential across a membrane that exactly opposes the net diffusion of a particular ion through the membrane.

Goldman Equation

An equation used to calculate the diffusion potential when the membrane is permeable to several different ions.

Resting Membrane Potential

The membrane potential of a cell in a quiescent or non-excited state.

Electrochemical Driving Force

The force that tends to cause movement of an ion across the membrane, determined by the difference between the membrane potential and the equilibrium potential of the ion.

Sodium-Potassium Pump

An active transport mechanism that pumps sodium ions out of the cell and potassium ions into the cell.

Action Potential

Rapid changes in the membrane potential that spread rapidly along the nerve fiber membrane.

Depolarization

The process by which the membrane potential becomes less negative.

Repolarization

The process by which the membrane potential returns to its resting state.

Voltage-Gated Sodium Channel

A sodium channel that opens or closes in response to changes in the membrane potential.

Voltage-Gated Potassium Channel

A potassium channel that opens or closes in response to changes in the membrane potential.

Activation Gate

The gate near the outside of the voltage-gated sodium channel that is closed in the normal resting membrane.

Inactivation Gate

The gate near the inside of the voltage-gated sodium channel that closes a few 10,000ths of a second after the activation gate opens.

Voltage Clamp Method

A method used to measure the flow of ions through specific channels by controlling the membrane potential.

Absolute Refractory Period

Period during which another action potential cannot be elicited, even with a strong stimulus.

Relative Refractory Period

A period immediately following the absolute refractory period when a stronger than normal stimulus is needed to elicit an action potential.

Saltatory Conduction

The jumping of action potentials from one node of Ranvier to the next in myelinated nerve fibers.

Increase in stimulus strength required to produce action potentials; occurs