AEMCA Practice Exam

What is the primary role of the coronary sinus?

1. To regulate heart rate

2. To drain blood from the heart muscle

3. To supply oxygenated blood to the heart

4. To control electrical impulses in the heart

The correct answer is: To drain blood from the heart muscle

The primary role of the coronary sinus is to drain blood from the heart muscle. The coronary sinus is a large vein located on the posterior side of the heart, which collects deoxygenated blood from the coronary veins that drain the myocardium (heart muscle). After the heart muscles have utilized the oxygen and nutrients from the blood, the deoxygenated blood returns through the coronary veins to the coronary sinus, which then empties the blood into the right atrium of the heart. This process is essential for maintaining the efficiency of the heart's functioning, as it ensures that the heart muscle can continuously receive refreshed blood while eliminating waste materials from cellular metabolism. In contrast, the other roles mentioned in the options do not pertain to the function of the coronary sinus. For instance, while the heart rate is influenced by electrical impulses generated by the sinoatrial node, this action does not involve the coronary sinus. Additionally, the supply of oxygenated blood to the heart is performed by the coronary arteries, rather than the coronary sinus.