Which of the following choices lists a correct sequence of events following the depolarization of transverse tubules in excitation-contraction coupling in cardiac muscle?
A) calcium release into cytosol, calcium ion influx through sarcolemma, actin and myosin attach, thin filaments slide toward the middle of sarcomeres
B) actin and myosin attach, thin filaments slide toward the middle of sarcomeres, calcium release into cytosol
C) calcium release into cytosol, actin and myosin attach, calcium ion influx through sarcolemma, thin myofilaments slide toward the middle of sarcomeres
D) calcium release into cytosol, actin and myosin attach, thin filaments slide toward the middle of sarcomeres, calcium ion influx through sarcolemma
E) calcium ion influx through sarcolemma, calcium release into cytosol, actin and myosin attach, thin myofilaments slide toward the middle of sarcomeres

Question

Quizplus · Accepted Answer

In cardiac muscle, depolarization of transverse tubules leads to calcium ion influx through the sarcolemma, which then triggers calcium release into the cytosol. This increase in calcium concentration allows actin and myosin to attach, leading to the sliding of thin myofilaments toward the middle of sarcomeres.

Which of the Following Choices Lists a Correct Sequence of Events