Where does the blood flow to after gas exchange has happened in alveoli?

After gas exchange has occurred in the alveoli of the lungs, the oxygen-rich blood flows back to the heart via the pulmonary veins. The pulmonary veins carry the oxygenated blood from the lungs to the left atrium of the heart. From the left atrium, the blood then flows into the left ventricle, which pumps it out to the rest of the body through the aorta.