MEDICAL PHYSIOLOGY

Detailed explanation-1: -The difference in the number of positively charged potassium ions (K+) inside and outside the cell dominates the resting membrane potential. The resting membrane potential is a result of different concentrations of Na+ and K+ ions inside and outside the cell.

Detailed explanation-2: -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-3: -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.

Detailed explanation-4: -Na+ is attracted to the inside of neurons at rest by two forces. First, the high concentration of Na+ outside the cell pushes it into the cell down the concentration gradient. Second, the electrical gradient, due to the negative charge within the neuron, tends to pull the positively charged ion inside in the cell.

Detailed explanation-5: -The sodium and chloride ion concentrations are lower inside the cell than outside, and the potassium concentration is greater inside the cell. These concentration differences for sodium and potassium are due to the action of a membrane active transport system which pumps sodium out of the cell and potassium into it.