As a result of the long refractory period generated by __________, cardiac muscle can not exhibit __________. A) the influx of calcium ions, tetanus (tetanic contractions) B) the out flow of K⁺, tetanus (tetanic contractions) C) the influx of Na⁺, tetanus (tetanic contractions) D) the influx of Ca⁺⁺, recruitment E) the out flow of K⁺, recruitment

Question

Quizplus · Accepted Answer

The influx of calcium ions generates a long refractory period in cardiac muscle, which prevents the muscle from exhibiting tetanus (tetanic contractions). The options involving outflow of potassium (K+) or influx of sodium (Na+) do not generate a significant refractory period in cardiac muscle. The option involving influx of calcium ions and recruitment does not make sense, as recruitment refers to the recruitment of more motor units in skeletal muscle, which does not apply to cardiac muscle.

As a Result of the Long Refractory Period Generated by __________