What is the typical membrane potential of a neuron at rest?

The typical membrane potential of a neuron at rest is around -70 mV, which is referred to as the resting membrane potential. This value is primarily determined by the distribution of ions across the neuronal membrane, particularly sodium and potassium ions. At rest, there is a higher concentration of potassium ions inside the neuron compared to the outside, while sodium ions are more concentrated outside.

The resting potential is maintained by the sodium-potassium pump, which actively transports potassium ions into the cell and sodium ions out of the cell. This action, along with the relatively higher permeability of the membrane to potassium compared to sodium, creates a negative charge inside the neuron in relation to the outside environment. Thus, -70 mV is established as a stable state to ensure that neurons are primed for action potentials when they receive appropriate stimuli.

Values such as +40 mV or 0 mV do not reflect the typical resting potential, as they indicate depolarized states. A membrane potential of -90 mV could indicate a hyperpolarized state, but this is not the standard resting potential for most neurons.