What is the function of the left atrium?

• A. The left atrium receives oxygenated blood from the lungs.
• B. The left atrium pumps blood to the body.
• C. The left atrium receives deoxygenated blood from the body.
• D. The left atrium delivers blood to the ventricles.

Answer: (A)

The left atrium’s job is to receive oxygenated blood from the lungs. Blood returns from the lungs via the pulmonary veins into the left atrium, and then moves through the mitral valve to the left ventricle to be pumped to the body. This chamber is the receiving reservoir for oxygen-rich blood, unlike the right side, which handles deoxygenated blood from the body.