What is Nostril?
[[File:Nostrils_by_David_Shankbone.jpg|thumb|Human nostrils]] A '''nostril''' (or '''naris''', pl. ''nares'') is one of the two holes of the [[nose]], from the point where they [[wikt:bifurcate|bifurcate]] to the external opening. In [[bird]]s and [[mammal]]s, they contain branched bones or [[cartilages]] called [[turbinate]]s, whose function is to warm air on inhalation and remove moisture on exhalation. [[Fish]] do not breathe through their noses, but they do have two small holes used for [[olfaction|smelling]] which may be called nostrils. In [[human]]s, the nasal cycle means that during the course of a day, the nostrils will switch over approximately every four hours or so, meaning that only one nostril is used at any one time.<ref>[http://www.webmd.com/content/article/4/1680_51935.htm?lastselectedguid=%7B5FE84E90-BC77-4056-A91C-9531713CA348%7D Nasal Obstruction]</ref> == References == <references/> [[Category:Nose]]