If the pacemaker cells in the SA node become more permeable to potassium ions,
A)the heart rate will increase.
B)the heart rate will decrease.
C)the membrane will depolarize.
D)the membrane will hyperpolarize.
E)both heart rate will decrease and membrane will hyperpolarize.

Question

Quizplus · Accepted Answer

When the pacemaker cells in the SA node become more permeable to potassium ions, it leads to an increased efflux of K+ from the cells. This results in hyperpolarization of the membrane, making it more negative and thus further from the threshold for depolarization. As a consequence, the rate of reaching the threshold for action potentials slows down, which decreases the heart rate. Therefore, both the heart rate will decrease and the membrane will hyperpolarize.

If the Pacemaker Cells in the SA Node Become More