Ii-alveoli zifumile ukuze zivumele i-oksijini ukuba ihambe isuke kwimiphunga ihamba kwangazo ii-alveoli iye kungena kwimithambo yegazi engoonobuyisa nakwii-cells zegazi elibomvu. I-Carbon dioxide idlula ivela egazini iye kungena kwii-alveoli. I-oksijini ithi yakubaninzi egazini ihambe ibuyele entliziyweni ize ke yona i-carbon dioxide ekwi-alveoli ityhilizelwe ngaphandle kwemiphunga ibe ngumoya esiwuphefumlela ngaphandle.