a Capillaries EXtensive branching Respiratory bronchiole of alveoli produces Alveolus Alveolar duct lots of surface area Alveolus for exchange between Alveolus air and blood Alveolar air Type ll cell Basement Alveolar and capillary walls are thin permitting rapid Interstitium diffusion of gases ype I cell Alveolar airExtensive branching of alveoli produces lots of surface area for exchange between air and blood. Alveolar and capillary walls are thin, permitting rapid diffusion of gases