Pacemaker cells have a resting potential that is the same as ventricular myocytes. true or false?

Pacemaker cells have a resting potential that is the same as ventricular myocytes. true or false?

• A. True
• B. False
• C. Not sure
• D. Depends on age

Answer: (B)

Pacemaker cells do not sit at the same resting potential as ventricular myocytes. Ventricular myocytes have a stable resting membrane potential around -85 to -90 mV, kept hyperpolarized mainly by a strong IK1 current. In contrast, pacemaker cells (like those in the SA node) do not have a fixed resting potential; they exhibit automaticity with a diastolic depolarization, starting from a less negative maximum diastolic potential around -60 to -50 mV. This gradual depolarization is driven by depolarizing currents, especially the funny current (If) through HCN channels, and it brings the membrane to threshold to fire an action potential. Because of this difference, the statement is false.

Pacemaker cells do not sit at the same resting potential as ventricular myocytes. Ventricular myocytes have a stable resting membrane potential around -85 to -90 mV, kept hyperpolarized mainly by a strong IK1 current. In contrast, pacemaker cells (like those in the SA node) do not have a fixed resting potential; they exhibit automaticity with a diastolic depolarization, starting from a less negative maximum diastolic potential around -60 to -50 mV. This gradual depolarization is driven by depolarizing currents, especially the funny current (If) through HCN channels, and it brings the membrane to threshold to fire an action potential. Because of this difference, the statement is false.