The physiological concentration of monovalent salt ions (primarily sodium, potassium, and chloride) in the human body is on the order of 0.15 molar (0.15 moles per liter or 150 moles per meter cubed). Let's assume that ions only within one nanometer (1x10-9 m) of the membrane cell wall participate in creating the resting and action potentials, which is also a few hundredths of a volt but with opposite polarity (during a pulse the potential outside the axon is temporarily smaller than the potential inside the axon). Considering your answer to the previous problem: a. Are very many of the ions transferred across the member to change the potential during a nerve pulse?
b. And what does this tell us about the change in concentration of the salt ions near the cell wall with respect to physiological concentrations?