Question

When a neuron is activated by a stimulus, its plasma membrane will change until it reaches a membrane potential of about 40 mV. What is special about this value

Answer 1

Answer: It is approximately the membrane potential at which the electrochemical gradient for Na+ is zero.

Explanation:

The charge in plasma membrane occurs with diffusion and electric fields.

For example, if there are two solutions, let's assume solution X and Solution Y are separated by a porous barrier (to diffuse in equal proportions).

The fundamental principle of diffusion states that solution from a high concentration diffuses to a lower concentration.

For instance, if the X solution contains 40 sodium ions and 40 chloride ions, the Y solution only has 30 sodium and 30 chloride ions. Due to the diffusion, these two solutions will mix and reach a steady-state.

The like charges repel, and opposite charges attract.