Nostril

The nostril is the external opening of the olfactive body of the animal , by which initially the air inspired passes, which is heated by the air expired, or refreshed in the areas very hot (In all the cases, the nasal zone behaves like a exchanging thermics).

Functions

The nostrils are active elements for several functional and anatomical systems:
  • Sense of smell
  • filtration of the air, gâce to an internal pilosity and the mucus secreted by Gland S allowing to imprison certain foreign bodies (which can be expelled by a sneeze Réflex E).
  • thermoghygrometric regulation of the air, sometimes playing (at the Emperor penquin for example) a true part of heat exchanger. The nostrils appear of a colder color on the photographs taken in the infra-red one. It should be noted that the tobacco, cafeine and the vasoconstrictive ones accentuate the cooling of this zone by decreasing their blood irrigation.
  • préhention in certain cases (Fourmilier S, éléphantidé S).

Particular cases:

- nostrils of the Suidé S (Wild boar, Peccary.) and of some digger animals (Mole) while being being very sensitive, consist of very solid fabrics and regenerating itself quickly. The Sanglier can thus plow the grounds and effectively excavate them to find its food there.
- Transformed into horn, the system nose-nostril of the elephant allows him proter of food to the mouth and to pump water of which it can be sprinkled, or to make “tuba” when it swims.

Anatomy and anatomical position

The nostrils are elements of flesh, which are pressed on the wing cartilages (wings of the nose). They contain muscular fabrics making it possible to dilate them or to close them (more or less according to the species).
On speaks about “osseous nostril” to indicate the hole which in the skeleton corresponds to the external nostril. At the Cetacea S (one speaks about vent) and reptiles amphibious, the nostrils often went back to the top of the head during the evolution, and they can be closed hermetically to prevent water from entering the lungs (Apnée).

The nostrils are generally close to the brain, but in certain animals (elephant, and perhaps certain dinosaurs, it can be distant about it). It is highly developed in the monkey nasic (Nasalis larvatus).

In the primates

The character “nostrils” presents 3 states:
  • Nostrils with a Rhinarium. It is the case of the Strepsirhinien S.
  • Narines without Rhinarium (with a Nez). It is the case of the Haplorhinien S.
    • drawn aside Narines, opened on the sides. It is the case of the Platyrhiniens.
    • brought closer Nostrils, opened towards bottoms. It is the case of the Catarhiniens.

At the Man

The nostrils are more or less broad or thick, narrowest at the populations of the white skin and broadest among Australian aboriginals. It often was and is again with the fashion of the Piercing, bored or decorated jewels, bone, Tatouage. Certain people (inuits) rub the nostrils to greet themselves

In the other animals

At the Poisson, an external nostril puts in contact the olfactive bag with outside.

At the Tétrapodes, there exists in more the choane , or nostril interns , in contact with the pharynx, which is the posterior opening of the nasal fossae which puts these last in communication with the Poumon S, conferring on the olfactive body a respiratory function .

Pathologies

At the time of the colds, seizes up, etc the nostrils can be irritated or present symptoms of Inflammation.
Des close symptoms is possible in the presence of devaporized and/or polluted air.

The nostrils can be the seat of cracks, ulcerations, crusts, buttons of Acné, black spots, Impetigo or buttons of fever due to the Herpès (small bouquet of yellowish blisters which burns and/or itches, oozes before being encrusted and to disappear (banal, but recurring and contagious lesion).

Certain specialized flies (ex: Lucilia will bufonivora ) lay in the nostrils of reptiles, Amphibians and mammals (exceptionnement at the Man); Their larvae (Maggot S) develop in the nasal fossae, before emerging via the nostrils.

Rem: Certain drugs are delivered via the nostrils (drops, aerosols.)
Certaines therapies washes the nasal fossae by means of thermal spring by making it enter by a nostril and leave by the other.

See too

External bonds

  • Document on the position of the nostrils of certain dinosaurs

Simple: Nostril

Random links:Domaize | ATC codes C01 | Saint-Brice (Seine-et-Marne) | List Peruvian newspapers | War of the Communities of Castille | Michael_Appleby_(Nouvelle_Zélande)