Neuroscience: Membrane Potential

Membrane Potential

Difference in electrical charge between inside and outside of a neuron.

Plasma membrane

Separates cell's interior from its environment.

Development of Membrane Potential

Due to grouping of ions on either side of the membrane.

Sodium Ions (Na+)

Positively charged, more prevalent outside the neuron.

Chloride Ions (Cl-)

Negatively charged, more prevalent outside the neuron.

Potassium Ions (K+)

Positively charged, more prevalent inside the neuron.

Organic Anions

Negatively charged, more prevalent inside the neuron.

Resting Membrane Potential

Inside of the neuron is more negative (around -70 millivolts).

Sodium-Potassium Pump

Transport protein that pumps three sodium ions out and two potassium ions into the cell.

Effect of Sodium-Potassium Pump

More positive ions are removed than added, maintaining the negative membrane potential.

Potassium Movement

Movement through ion channels allows K+ to exit until equilibrium is reached, stabilizing the resting membrane potential at about -65 to -70 mV.