If we were able to artificially alter the membrane permeability of pacemaker cells so that sodium influx is more rapid,________.
A) tetanic contraction would occur due to the short absolute refractory period of cardiac muscle
B) threshold is reached more quickly and heart rate would increase
C) potassium channels compensate and no change in heart rate would occur
D) heart rate would decrease, but blood pressure would rise due to the excess sodium present

Question

Quizplus · Accepted Answer

If sodium influx is increased, threshold would be reached more quickly and the heart rate would increase. This is because pacemaker potentials and subsequent action potentials are generated by the influx of calcium and sodium ions.

If We Were Able to Artificially Alter the Membrane Permeability