NHA Phlebotomy Certification Practice Exam

Which structure is the first to receive deoxygenated blood returning from the body?

1. Left Atrium

2. Right Atrium

3. Right Ventricle

4. Vena Cave

The correct answer is: Right Atrium

The structure that is the first to receive deoxygenated blood returning from the body is the right atrium. Blood from the systemic circulation returns to the heart via two large veins called the superior and inferior vena cavae, which empty directly into the right atrium. Once the right atrium fills with deoxygenated blood, it contracts and sends this blood into the right ventricle, which then pumps it to the lungs for oxygenation. The left atrium, on the other hand, receives oxygenated blood from the lungs, not deoxygenated blood from the body. The right ventricle is significant in the pathway of blood flow but is not the first structure to receive the returning deoxygenated blood. The vena cavae are the vessels that transport the deoxygenated blood to the heart, not a chamber of the heart itself. Thus, the right atrium is the correct structure for receiving deoxygenated blood first in the circulatory pathway.