Action potentials in contractile cardiac muscle cells
A) are much faster than action potentials in skeletal muscle.
B) have no plateau phase.
C) involve voltage-gated calcium ion channels.
D) have sodium ion channels that open and cause repolarization.
E) have all of these characteristics.

Question

Quizplus · Accepted Answer

Action potentials in contractile cardiac muscle cells involve voltage-gated calcium ion channels. None of the other choices are true; action potentials in cardiac muscle cells are slower than in skeletal muscle, do have a plateau phase, and have sodium ion channels that open and cause depolarization, not repolarization.

Action Potentials in Contractile Cardiac Muscle Cells