Factors that affect the velocity of pulmonary gas exchange Thickness of respiratory membrane呼吸膜 a Surface area of respiratory membrane The diffusion coefficient扩散系数 of the gas a The pressure difference of the gas between the two sides of the membraneFactors that affect the velocity of pulmonary gas exchange ◼ Thickness of respiratory membrane呼吸膜 ◼ Surface area of respiratory membrane ◼ The diffusion coefficient 扩散系数of the gas ◼ The pressure difference of the gas between the two sides of the membrane