Fick’s First Law of Diffusion and Lung Gas Exchange *EXPLAINED*

Fick’s First Law of Diffusion states that the rate of gas exchange across a membrane is directly proportional to the surface area of the membrane, the concentration gradient of the gas, and the diffusion coefficient of the gas in the membrane. In the context of lung gas exchange, this law explains how oxygen and carbon dioxide are able to diffuse across the thin respiratory membrane in the alveoli. The large surface area of the alveoli, the steep concentration gradient between the alveolar air and the blood, and the high diffusion coefficients of oxygen and carbon dioxide all contribute to efficient gas exchange in the lungs. This law is crucial for understanding how gases are exchanged in the lungs to facilitate respiration and maintain proper oxygen levels in the blood.