Anatomy of the respiratory system

Nose breathing is typically through the nose. This confers two advantages, there is improved ltration by vibrissae hairs and humidi cation of inspired gas because the nasal septum and the turbinates greatly increase the surface area of muscosa available for evaporation and the turbulent ow improves contact. The consequence is increased resistance to ow such that at higher ows (>35 l/min) oral breathing is required.