Air normally enters the nose where it is:
|2.||Filtered from large particles|
These three functions are performed as the air passes over ridges named the
Superior, middle and inferior conchea and also as the air passes through the folds between the conchea termed the superior, middle and inferior meatus.
All these structures are highly vascularised and moistened by copious amount of mucus. This rich blood supply causes the air to be warmed to almost body temperature. As hot air can contain a higher amount of moisture, the air is also humidified to almost 100% as it passes through the nose.
Apart from heating and moistening the air, the conchea produce turbulence in the incoming air. This turbulence would induce any large particles including dust and bacteria, to stick to the mucus. Thus the air is also filtered as it is passing through the nose. This function is complimented by the presence of hairs at the entrance of the nose that trap the very large particles.
Apart from the "airconditioning" function, the nose accommodates the sense of smell, through the presence of special neuroepithelium . These sensory nerve endings are stimulated by chemicals that dissolve in the moist coating. Vocal sounds are also produced in the nasal cavity thus aiding in vocalisation.