MEDICAL PHYSIOLOGY

Detailed explanation-1: -A neuron is at rest when it is not sending an an electrical signal. During this time, the inside of the neuron is negative relative to the outside.

Detailed explanation-2: -A neuron at rest is negatively charged: the inside of a cell is approximately 70 millivolts more negative than the outside (−70 mV, note that this number varies by neuron type and by species).

Detailed explanation-3: -Neurons actually have a pretty strong negative charge inside them, in contrast to a positive charge outside. This is due to other molecules called anions. They are negatively charged, but are way too big to leave through any channel. They stay put and give the cell a negative charge inside.

Detailed explanation-4: -However, the movement of only the cation from the inside of the cell to the outside of the cell leaves behind a negative anion, and thus the inside of the cell becomes more negative, while the outside of the cell becomes more positive. This generates an electrostatic gradient that builds up over time.

Detailed explanation-5: -Key Points. When the neuronal membrane is at rest, the resting potential is negative due to the accumulation of more sodium ions outside the cell than potassium ions inside the cell.