Tetanic Muscle Contractions Don't Occur in a Normal Cardiac Muscle

Question

Tetanic muscle contractions don't occur in a normal cardiac muscle because
A) cardiac muscle tissue contracts on its own.
B) neural stimulation is lacking.
C) the refractory period lasts until the muscle relaxes.
D) the refractory period ends before the muscle reaches peak tension.
E) potassium channels outnumber sodium channels.

Accepted Answer

In cardiac muscle, the refractory period (a period when the muscle cannot be stimulated) lasts until the muscle relaxes, which prevents tetanic contractions. Tetanic contractions occur when the muscle is stimulated repeatedly before it has a chance to relax, leading to sustained contraction without relaxation.