Resting Membrane Potential

Resting Membrane Potential

The membrane potential of an excitable cell when it is at rest

Resting Membrane Potential: Cause

A small buildup of negative ions inside the cell and positive ions outside the cell creates a separation of charge across the membrane, producing the resting membrane potential.

Resting Membrane Potential: Charge Distribution

The inside of the membrane is relatively negative, while the outside is relatively positive.

Membrane Potential

The voltage difference between the inside and outside of a biological cell that’s often measured in millivolts (mV).

Membrane Potential: Difference

The greater the difference in charge across the membrane, the larger the membrane potential

Resting Membrane Potential: Neuron Range

In neurons, the resting membrane potential usually ranges from −40 to −90 mV.

Resting Membrane Potential: Typical Value

A typical resting membrane potential of a neuron is about −70 mV.

Resting Membrane Potential: Meaning of Negative Sign

The negative sign means the inside of the neuron is electrically negative relative to the outside.

Membrane Potential: Polarized Cell

A cell with a membrane potential is described as polarized because there is a difference in electrical charge between the inside and outside of the cell.

Membrane Potential: Polarized Cell: Body Cells

The membrane potential of different types of body cells can range from about +5 mV to −100 mV.

Resting Membrane Potential: Three Major Factors

• Unequal distribution of ions in the ECF and cytosol

• Inability of most anions to leave the cell

• Electrogenic nature of the Na+ –K+ ATPases