AEMCA Practice Exam

What are the three openings into the right atrium?

1. Mitral valve, tricuspid valve, aorta

2. Superior vena cava, inferior vena cava, coronary sinus

3. Pulmonary veins, aorta, superior vena cava

4. Left atrial appendage, left ventricle, inferior vena cava

The correct answer is: Superior vena cava, inferior vena cava, coronary sinus

The right atrium of the heart receives blood from three main structures: the superior vena cava, inferior vena cava, and coronary sinus. The superior vena cava is responsible for collecting deoxygenated blood from the upper body, including the head, neck, arms, and upper torso. The inferior vena cava serves a similar function but collects blood from the lower parts of the body, such as the legs and lower abdomen. Meanwhile, the coronary sinus is a collection of veins that empties directly into the right atrium, carrying deoxygenated blood from the heart muscle itself. Together, these three openings facilitate the efficient return of deoxygenated blood to the heart, ensuring that the right atrium has a continuous supply of blood before it is pumped into the right ventricle and eventually to the lungs for oxygenation. The other options do not accurately depict the openings into the right atrium, as they include structures that either do not connect directly to the right atrium or relate to different chambers of the heart or systemic circulation.