Where does the left atrium receive blood from?

The left atrium receives blood from the lungs. This blood is oxygen-rich, having been freshly oxygenated in the alveoli of the lungs. It enters the left atrium via the four pulmonary veins, two from each lung. This process is a key part of the circulatory system, ensuring that oxygenated blood is delivered to the heart before being pumped into the left ventricle and then out to the rest of the body.

The other options represent different sources of blood for various heart chambers. The body primarily sends deoxygenated blood to the right atrium, the right atrium directly receives blood from systemic circulation, and the left ventricle pumps blood out to the aorta, but does not send blood back to the left atrium. Understanding the flow of blood through these chambers is essential for comprehending how oxygen and nutrients are delivered throughout the body.