The membrane potential of most cells . The membrane potential of most cells . is determined primarily by sodium is negative, except when there is a change in membrane permeability to ions results in a net negative electrical charge in the body is negative at all times

is negative, except when there is a change in membrane permeability to ions

Explanation:

Membrane potential is voltage that result from differences in Ion concentration of cellular membrane.

Many Ions such as potassium(K+), Sodium(Na+)and chlorine(cl-) has many gradient across the membrane this gives the potential energy. If the membrane is permeable it gives rise to intake of potassium, leading to diffusion of positive charged Ion down the gradient outside the cell leading to a concentration of uncompensated net negative charge.

Hence, the membrane potential is mostly negative except there is a change in members permeability to Ion

it is called the mitotic spindle