How many chambers does the heart have?

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

Answer: (C)

The heart uses four chambers to keep blood flow organized and to keep oxygen-poor and oxygen-rich blood separate. The two upper chambers are the atria, which receive blood, and the two lower chambers are the ventricles, which pump blood onward. Blood returning from the body enters the right atrium, moves to the right ventricle, and is sent to the lungs to be oxygenated. Oxygenated blood returns to the left atrium, passes into the left ventricle, and is pumped out to the rest of the body. This four-chamber setup ensures a one-way flow and proper separation of the two blood streams. If there were only two chambers, the separation wouldn’t be achieved; with fewer than four, a chamber would be missing, and with more, you’d have extra structures that aren’t present in normal anatomy.