Why can't tetany of the heart occur?
A) there are no distinct motor units in the heart.
B) there is inadequate oxygen supply via the coronary circulation to metabolically support a sustained contraction.
C) the refractory period in cardiac muscle lasts almost as long as the duration of the resultant contraction.
D) the heart contracts with maximal force every beat so it is impossible to increase the strength of cardiac contraction.
E) vagal stimulation slows down the heart rate to prevent summation of contractions.

Question

Quizplus · Accepted Answer

The refractory period in cardiac muscle lasts almost as long as the duration of the resultant contraction, meaning that the heart cannot be stimulated to contract before it has completely relaxed, preventing tetany of the heart.

Why Can't Tetany of the Heart Occur