Movement of particles across a membrane from areas of high concentration to low concentration
Gases move from areas of high pressure to low pressure Total pressure of air includes the partial pressure of each gas in the air
Partial pressure of oxygen is higher in alveoli air than in capillary blood Which way will oxygen diffuse? Partial pressure of carbon dioxide is higher in capillary blood than in alveoli air Which way will carbon dioxide diffuse?
Blood flow (to body tissues) Alveolus Diffusion of O 2 P CO 2 = 40 mm Hg P O 2 = 104 mm Hg Capillary Alveolar wall Blood flow (from body tissues) P CO 2 = 40 mm Hg P O 2 = 104 mm Hg P CO 2 = 45 mm Hg P O 2 = 40 mm Hg