Final answer:
The excitation-contraction coupling in cardiac muscle involves various steps, including action potential propagation, calcium ion influx, and calcium binding. However, calcium binding to calmodulin in the cytosol is not a part of this process.
Step-by-step explanation:
The excitation-contraction coupling in cardiac muscle involves several steps. A) An action potential travels along transverse tubules (T-tubules) to reach the sarcoplasmic reticulum (SR) membrane. B) Calcium channels in the plasma membrane open, allowing calcium ions (Ca++) to enter the cell. C) Calcium channels in the SR open, allowing calcium ions to enter the cytosol. D) Calcium binds to calmodulin in the cytosol. E) Calcium opens calcium channels in the SR.