MEDICAL PHYSIOLOGY

Detailed explanation-1: -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-2: -The resting membrane potential of a neuron is about-70 mV (mV=millivolt)-this means that the inside of the neuron is 70 mV less than the outside. At rest, there are relatively more sodium ions outside the neuron and more potassium ions inside that neuron.

Detailed explanation-3: -Na+ is more concentrated outside than inside the cell.

Detailed explanation-4: -For a typical neuron at rest, sodium, chloride, and calcium are concentrated outside the cell, whereas potassium and other anions are concentrated inside.

Detailed explanation-5: -Because there are many more sodium ions on the outside, and the inside of the neuron is negative relative to the outside, sodium ions rush into the neuron. Remember, sodium has a positive charge, so the neuron becomes more positive and becomes depolarized. It takes longer for potassium channels to open.