Cell Physiology II: Ions, Action Potential, & Electrolyte Imbalance

These flashcards cover key vocabulary and concepts related to cell physiology, particularly focusing on fluid compartments, action potentials, and electrolyte balance.

Extracellular Fluid (ECF)

Fluid found outside cells, including plasma and interstitial fluid.

Intracellular Fluid (ICF)

Fluid found inside cells, making up about 40% of total body weight.

Transmembrane Potential

The voltage difference across a cell membrane, typically around -70mV at resting state.

Passive Channels

Channels that are always open and allow ions to pass through based on concentration gradients.

Active Channels

Channels that open or close in response to stimuli, regulating ion flow.

All-or-None Principle

An action potential is triggered if a stimulus exceeds a certain threshold, regardless of the intensity of the stimulus.

Refractory Period

A period during which a neuron cannot fire another action potential, divided into absolute and relative phases.

Hypernatremia

Condition characterized by high sodium levels in the blood.

Hyponatremia

Condition characterized by low sodium levels in the blood.

Hyperkalemia

Condition characterized by high potassium levels in the blood.

Hypokalemia

Condition characterized by low potassium levels in the blood.

Sodium-Potassium Exchange Pump

A mechanism that uses ATP to transport sodium out of and potassium into cells, maintaining concentration gradients.

Action Potential

A short-lived change in transmembrane potential that propagates along nerve cells.

Depolarization

The process in which the membrane potential becomes more positive due to the influx of Na+ ions.

Repolarization

The return of the membrane potential to its resting state following depolarization, primarily due to K+ exiting the cell.

Equilibrium Potential

The membrane potential at which the net flow of a particular ion across the membrane is zero.