How the Flow of blood and gas exchange?

The flow of blood in the body is facilitated by the pumping action of the heart, which carries oxygenated blood from the lungs to the rest of the body and returns deoxygenated blood to the lungs for reoxygenation. Gas exchange occurs primarily in the alveoli of the lungs, where oxygen from the air diffuses into the bloodstream and carbon dioxide is released from the blood into the air to be exhaled.