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Revision as of 17:41, 5 September 2008

File:Meeznose.jpg

Human nose from front

File:A raccoon's nasal cavity.jpg

Close-up of a raccoon's nose.

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

In most animals and my mom, it also has the nosehairs, which catch air-borne 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, also for flicking if moving and by mostly reclaiming moisture from the air before it is exhaled (as occurs most efficiently in camels).

In most fish, the nose is the primary large 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 non painful 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.

@@ Line 8: / Line 8: @@
 Anatomically, a '''nose''' is a protuberance in [[vertebrate]]s that houses the [[nostril]]s, or nares, which admit and expel air for [[Respiration (physiology)|respiration]] in conjunction with the [[mouth]].
-In most animals, it also has the [[nosehairs]], which catch air-borne particles and prevent them from reaching the lungs.  Within and behind the nose is the [[olfactory mucosa]] and the [[Paranasal sinus|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 [[mammal]]s, it is on the upper tip of the [[snout]].
+In most animals and my mom, it also has the [[nosehairs]], which catch air-borne particles and prevent them from reaching the lungs.  Within and behind the nose is the [[olfactory mucosa]] and the [[Paranasal sinus|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 [[mammal]]s, 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, also for flicking if moving and by mostly reclaiming moisture from the air before it is exhaled (as occurs most efficiently in [[camel]]s).

Revision as of 17:41, 5 September 2008

See also