MEDICAL PHYSIOLOGY

Detailed explanation-1: -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-2: -There is a higher concentration of potassium ions on the inside of the cell than on the outside. Each potassium ion (on either side of the membrane) is balanced by an anion, so the system as a whole is electrically neutral.

Detailed explanation-3: -The sodium and chloride ion concentrations are lower inside the cell than outside, and the potassium concentration is greater inside the cell.

Detailed explanation-4: -Since there is resistance to the passage of Na+ across the neuronal membrane, an active pump is able to maintain the higher concentration of Na+ outside the neuron. K+ is found in higher concentrations inside the neuron at rest.

Detailed explanation-5: -The inside of the neuron is more negatively charged than the outside. Figure 4.1. For a typical neuron at rest, sodium, chloride, and calcium are concentrated outside the cell, whereas potassium and other anions are concentrated inside. This ion distribution leads to a negative resting membrane potential.