NHA Phlebotomy Certification Practice Exam

Which type of blood vessels carry deoxygenated blood to the heart?

1. Arteries

2. Alveoli

3. Capillaries

4. Veins

The correct answer is: Veins

Veins are the blood vessels responsible for carrying deoxygenated blood back to the heart. This is a crucial function in the circulatory system, as the veins collect blood that has already delivered its oxygen and nutrients to the tissues and is returning to be re-oxygenated in the lungs. The structure of veins, which includes valves to prevent backflow and a thinner muscular wall compared to arteries, facilitates this return of blood. They are generally located closer to the surface of the body and have a greater capacity to hold blood, making them efficient conduits for deoxygenated blood. In contrast, arteries carry oxygenated blood away from the heart to deliver it to organs and tissues. Alveoli are structures in the lungs where gas exchange occurs, and capillaries are the smallest blood vessels that connect arterioles and venules, allowing for the exchange of oxygen, carbon dioxide, nutrients, and waste between blood and tissues. Therefore, veins are specifically designated for transporting deoxygenated blood back to the heart, making them the correct answer to the question.