Breathing and gas exchange

Category A - full version without watermark 1024x576 (check terms and conditions at The version with watermark is for free to embed. Breathing takes oxygen in and carbon dioxide out of the body. Breathing is only part of the processes of delivering oxygen to where it is needed in the body and removing carbon dioxide waste. The process of gas exchange occurs in the alveoli by passive diffusion of gases between the alveolar gas and the blood passing by in the lung capillaries. Once in the blood the heart powers the flow of dissolved gases around the body in the circulation.