THE SENSE OF SMELL The nose is normally mistakenly assumed to be the organ of smell reception. It is not. The primary function of the nose is to regulate the temperature and humidity of inspired air, thereby protecting the delicate linings of the lungs. This is achieved by the breathed air passing through narrow passageways formed by three nasal turbinates in each nostril. The turbinates are covered by spongy vascular cells which can expand or contract to open or close the nasal pathways. The olfactory receptors, innervated by the 1st cranial nerve, are located at the top of the nose. There...