Structures of pulmonary ventilation 1. Respiratory muscle Primary muscles of respiration: external intercostals(iJ 间外肌)& diaphragm(膈肌) air enters r leaves ribcage moves ribcage moves up and out down and in lungs expand lungs get smaller diaphragm moves down diaphragm moves up Inhalation ExhalationStructures of pulmonary ventilation 1. Respiratory muscle Primary muscles of respiration: external intercostals (肋 间外肌)& diaphragm（膈肌）