A physician has ordered the measurement of a cardiac patient's electrolyte levels as part of the client's morning blood work
Which of the following statements best captures the importance of potassium in the normal electrical function of the patient's heart?
A)
Potassium catalyzes the metabolism of ATP, producing the gradient that results in electrical stimulation.
B)
Potassium is central to establishing and maintaining the resting membrane potential of cardiac muscle cells.
C)
The impermeability of cardiac cell membranes to potassium allows for action potentials achieved by the flow of sodium ions.
D)
The reciprocal movement of one potassium ion for one sodium ion across the cell membrane results in the production of an action potential.
Ans:
B
Feedback:
The selective permeability of cell membranes to potassium, and its near-impermeability to sodium ions, produces the resting membrane potential of cardiac cells. Potassium does not catalyze the metabolism of ATP, and sodium and potassium ions do not move across the cell membrane in a 1:1 ratio.
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