How many chambers does the heart have?

• A. Two
• B. Three
• C. Four
• D. Five

Answer: (C)

Four chambers organize the heart into two functional pumps. The upper chambers are atria that receive blood, and the lower chambers are ventricles that pump it out. On the right side, the atrium collects deoxygenated blood from the body and passes it to the right ventricle, which sends it to the lungs for oxygen. On the left side, the atrium collects oxygenated blood from the lungs and passes it to the left ventricle, which distributes it to the rest of the body. This setup keeps the two blood streams separate and ensures one-way flow through the heart with the help of valves. If there were only two chambers, the system wouldn’t be able to separate oxygen-rich from oxygen-poor blood efficiently; three chambers still mix blood in a single ventricle, and five would add an extra chamber that humans don’t have. So, having four chambers is the correct count.