Membrane Potential

Membrane Potential

The difference in the electrical potential between the inside and outside of the cell.

Separation of Charges

The difference of positive and negative ions in extracellular fluid (ECF) and intracellular fluid (ICF).

Extracellular Fluid (ECF)

The fluid outside the cell.

Intracellular Fluid (ICF)

The fluid inside the cell.

Resting Membrane Potential

The membrane potential of a cell at rest, typically around -70 mV.

Describe Sodium’s concentration

An ion that is more concentrated in the ECF than in the ICF.

Describe Potassium concentration

An ion that is more concentrated in the ICF than in the ECF.

Describe Anionic Proteins

A negatively charged protein that is concentrated in the ICF and impermeable to the plasma membrane.

Sodium-Potassium Pumps

Mechanisms that maintain the concentration gradients of Na+ and K+ across the plasma membrane.

Relative Permeability

A measure of how easily an ion can move across the membrane; K+ has higher relative permeability than Na+.

Equilibrium Potential for K+

approximately -90 mV.

Equilibrium Potential for Na+

approximately +60 mV.

Polarization

A state where the membrane potential has a charge different from 0 mV.

Depolarization

The process of the membrane potential becoming more positive, moving closer to 0 mV.

Repolarization

The process of returning to the resting membrane potential, becoming more negative after depolarization.

Hyperpolarization

A state where the membrane potential becomes more negative than the resting membrane potential.