Final answer:
Deoxygenated blood from the myocardium is collected by the coronary sinus, which then empties into the right atrium of the heart, assisting in the cardiac cycle.
Step-by-step explanation:
The deoxygenated blood from the myocardium flows into a thin-walled vein called the coronary sinus, which empties into the right atrium. The right atrium is an essential component of the heart's circulatory system, serving as the receiving chamber for blood that is returning from the systemic circulation. There are two other major veins that drain into the right atrium: the superior and inferior venae cavae, which carry blood respectively from above and below the diaphragm. The coronary sinus collects deoxygenated blood from the myocardium through the coronary veins, thus playing a crucial role in the cardiac cycle.