What are the determinants of membrane potential?

Membrane potentials in cells are determined primarily by three factors: 1) the concentration of ions on the inside and outside of the cell; 2) the permeability of the cell membrane to those ions (i.e., ion conductance) through specific ion channels; and 3) by the activity of electrogenic pumps (e.g., Na+/K+-ATPase and …

What determines the membrane potential of a neuron?

A resting (non-signaling) neuron has a voltage across its membrane called the resting membrane potential, or simply the resting potential. The resting potential is determined by concentration gradients of ions across the membrane and by membrane permeability to each type of ion.

What regulates membrane potential?

As explained above, the potential at any point in a cell’s membrane is determined by the ion concentration differences between the intracellular and extracellular areas, and by the permeability of the membrane to each type of ion.

What causes membrane potential to change?

Potassium ions (K+) are at a high concentration inside of neurons. The membrane potential can change over time, allowing signals to be transmitted. These changes in membrane potential are caused by particular ion channels opening and closing, and thereby changing the conductance of the membrane to the ions.

What is the primary determinant of the resting membrane potential?

K+ movement is the primary determinant of the resting potential. It is found in much higher concentration inside the cell (150mM) than outside the cell (5mM).

How do neurons alter their membrane potential?

The nucleus of a neuron is located in the cell body. In neurons, stimuli can alter this potential difference by opening sodium channels in the membrane. For example, neurotransmitters interact specifically with sodium channels (or gates). So sodium ions flow into the cell, reducing the voltage across the membrane.

What triggers depolarization?

Depolarization is caused when positively charged sodium ions rush into a neuron with the opening of voltage-gated sodium channels. Repolarization is caused by the closing of sodium ion channels and the opening of potassium ion channels.

What triggers an action potential?

Action potentials are caused when different ions cross the neuron membrane. A stimulus first causes sodium channels to open. Because there are many more sodium ions on the outside, and the inside of the neuron is negative relative to the outside, sodium ions rush into the neuron.