The period during the cardiac cycle when cells cannot respond to a stimulus, no matter how strong, is called the _____ period.
A) depolarized
B) supranormal
C) relative refractory
D) absolute refractory

Question

Quizplus · Accepted Answer

During the absolute refractory period, the cell will not respond to further stimulation. This means that the myocardial working cells cannot contract and the cells of the electrical conduction system cannot conduct an electrical impulse-no matter how strong the stimulus. As a result, tetanic (sustained) contractions cannot be provoked in cardiac muscle. On the ECG, the absolute refractory period corresponds with the onset of the QRS complex to the peak of the T wave. Depolarized is the electrical activity coming back to a baseline level, to the isoelectric line. Supranormal is the electrical potential of the cell. Relative refractory is when the cell requires a stronger than normal stimulus to produce a contraction.

The Period During the Cardiac Cycle When Cells Cannot Respond