Which of the following would increase heart rate?
A) increased sympathetic stimulation of SA node
B) decreased parasympathetic stimulation of nodal fibers
C) increased levels of norepinephrine and/or epinephrine
D) faster depolarization of the pacemaker potential
E) all of the above

Question

Quizplus · Accepted Answer

All of the above choices can cause an increase in heart rate. Increased sympathetic stimulation of the SA node and decreased parasympathetic stimulation of nodal fibers both result in a faster rate of depolarization of the pacemaker potential, which leads to an increased heart rate. Additionally, an increase in levels of norepinephrine and/or epinephrine can also stimulate the SA node and increase the heart rate.

Which of the Following Would Increase Heart Rate