EXTERNAL RESPIRATION: UNLOADING CO2 cO Carbon dioxide diffuses along its partial pressure P 2=4co gradient, from the cO blood into the alveolus. until equilibrium is reache PCOg= 45 am Hg PCO2=40 mm Hg Equilbrium is reached within the first four tenths of the capillary 出自8 Graph Pressure gauge Time(seconds) 0.25 05 075