A Patient Being Evaluated for Cardiac Pathology Asks the Nurse

A patient being evaluated for cardiac pathology asks the nurse why sodium, calcium, and potassium are so important in his diet. What is the nurse's best response?

A) "The action potentials of the heart muscle cells are dependent upon the diffusion of sodium, potassium and calcium across the cell membrane."
B) "Because you are on potassium supplements, it is important to monitor electrolytes."
C) "Heart rate is affected by the oxygen levels in your body, which involves the attachment of oxygen molecules to these electrolytes."
D) "It is the pacemaker of your heart that is responsible for the heart beat."