Gas exchange is a process in biology where gases contained in an organism and atmosphere transfer or exchange. In human gas-exchange, gases contained in the blood of human bodies exchange with gases contained in the atmosphere. Human gas-exchange occurs in the lungs. In unicellular organisms the respiratory surface and gas-exchange is governed by Fick's law. In humans and mammals, respiratory gas exchange is carried out by mechanisms of the heart and lungs. Ventilation is the process of air movement into and out of the lungs. Once air enters the lungs, diffusion of O2 and CO2 occurs in the alveoli. The oxygenated blood is then perfused throughout the body where gas exchange occurs in the capillary beds.
Read more about Gas Exchange: Pulmonary Physics, Interchange, Diffusion, Control of Respiration
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