Nose



Anatomically, a nose is a protuberance in vertebrates that houses the nostrils, or nares, which admit and expel air for respiration.

In mammals
In most mammals, it also houses the nosehairs, which catch airborne particles and prevent them from reaching the lungs. Within and behind the nose is the olfactory mucosa and the sinuses. Behind the nasal cavity, air next passes through the pharynx, shared with the digestive system, and then into the rest of the respiratory system. In humans, the nose is located centrally on the face; on most other mammals, it is on the upper tip of the snout.

As an interface between the body and the external world, the nose and associated structures frequently perform additional functions concerned with conditioning entering air (for instance, by warming and/or humidifying it) and by mostly reclaiming moisture from the air before it is exhaled (as occurs most efficiently in camels).

In most mammals, the nose is the primary organ for smelling. As the animal sniffs, the air flows through the nose and over structures called turbinates in the nasal cavity. The turbulence caused by this disruption slows the air and directs it toward the olfactory epithelium. At the surface of the olfactory epithelium, odor molecules carried by the air contact olfactory receptor neurons which transduce the features of the molecule into electrical impulses in the brain.

In cetaceans, the nose has been reduced to the nostrils, which have migrated to the top of the head, producing a more streamlined body shape and the ability to breathe while mostly submerged. Conversely, the elephant's nose has become elaborated into a long, muscular, manipulative organ called the trunk.



Human nose
The visible part of the human nose is the protruding part of the face that bears the nostrils. The shape of the nose is determined by the ethmoid bone and the nasal septum, which consists mostly of cartilage and which separates the nostrils.

Associated health risks
Because of the special nature of the blood supply to the human nose and surrounding area, it is possible for retrograde infections from the nasal area to spread to the brain. For this reason, the area from the corners of the mouth to the bridge of the nose, including the nose and maxilla, is known to doctors as the danger triangle of the face.

Shapes of the human nose
Human noses can take many different shapes; every individual has in fact a uniquely shaped nose. Several attempts have been made towards a classification of noses. The following examples are from Nasology by Eden Warwick (pseudonym of George Jabet). This 19th century tract associated nose shapes with character traits in a way akin to phrenology, in a somewhat ironical way, as the booklet was intended to mock the popular but highly controversial subject of phrenology.
 * Class I: The Roman, or Aquiline nose, which is rather convex, but undulating as its name aquiline imports. (See: Hooknose)
 * Class II: The Greek or Straight nose, which is perfectly straight
 * Class III: The African, or Wide-nostrilled nose, wide at the end, thick and broad, gradually widening from below the bridge. The other noses are seen in profile, but this one in full face.
 * Class IV: The Hawk nose, which is very convex, and preserves its convexity like a bow. It is thin and sharp
 * Class V: The Snub nose
 * Class VI: The Turn-up or Celestial nose, with a continuous concavity from the eyes to the tip

Culture
Some people choose to get rhinoplasty to change the aesthetic appearance of their nose. Nose piercings are also common, such as nostril, septum or bridge.

In New Zealand, nose pressing ("hongi") is a traditional greeting.

People famous for their noses

 * John Barrymore known as "The Great Profile"
 * Cyrano de Bergerac
 * Jimmy Durante
 * W.C. Fields
 * Michael Jackson known for having multiple plastic surgery on his nose.
 * Major Kovatzov in Nikolai Gogol's novel The Nose.
 * Barry Manilow known for his large nose, often parodied ,
 * Jack Nicholson in the film Chinatown (1974) by Roman Polanski