Action Potentials & Ion Movements

These flashcards cover key vocabulary terms related to action potentials and ion movements in neurons, providing definitions to aid in understanding the physiological concepts discussed in the lecture.

Extracellular Fluid (ECF)

Fluid outside the cells, primarily comprised of sodium ions.

Intracellular Fluid (ICF)

Fluid inside the cells, primarily comprised of potassium ions.

Resting Membrane Potential

The electrical charge difference across the membrane of a neuron when it is not transmitting a signal, typically at -70 mV.

All-or-None Principle

The principle that an action potential will fire at full strength once the threshold is reached, regardless of the strength of the stimulus.

Depolarization

The process during an action potential where the membrane potential becomes more positive, usually due to the influx of Na+ ions.

Repolarization

The phase in an action potential where the membrane potential returns to a more negative value, primarily due to the efflux of K+ ions.

Hyperpolarization

The state where the membrane potential becomes more negative than the resting potential, typically due to K+ channels remaining open.

Gated Channels

Ion channels that open and close in response to stimuli, helping regulate the movement of specific ions across the membrane.

Sodium-Potassium Pump

A cellular mechanism that uses ATP to transport sodium ions out of the cell and potassium ions into the cell, maintaining concentration gradients.

Refractory Period

The period during which a neuron cannot generate another action potential, divided into absolute and relative refractory periods.