Question

Which of the following do you think contribute to the inability of cardiac muscle to be tetanized?

a) Presence of intercalated discs
b) Lack of calcium ions
c) Absence of striations
d) Slow conduction of action potentials

Answer 1

The inability of cardiac muscle to be tetanized is primarily due to the slow conduction of action potentials and the sustained depolarization plateau resulting from the influx of calcium ions through voltage-gated calcium channels.

Step-by-step explanation:

The inability of cardiac muscle to be tetanized is primarily due to the slow conduction of action potentials.

Cardiac muscle cells have a longer action potential with a sustained depolarization plateau compared to skeletal muscle. This plateau is produced by the influx of calcium ions through voltage-gated calcium channels in the sarcolemma of cardiac muscle fibers.

The calcium ions are essential for cardiac muscle contraction. Without the calcium influx, the myosin heads cannot form cross-bridges with actin, preventing sustained contraction.