This article overlaps thematically with [[smelling mucous membrane]] {{#if: | and [[{{{3}}}]]}} {{#if: | and [[{{{4}}}]]}}. Help to define or combine the articles better from each other. You find a guidance for the use of the collecting main and a list of the past multiple entries under Wikipedia: Article to the same topic. Askthere expresses you, before you remove the component.Density 20:08, 27. November 2005 (CET)

the smell (lat. Olfactus=Geruch, olfaktorische perception) is the interpretation of the excitations, which are supplied by the chemoreceptors in the smell organ to the brain of the respective organism. In certain areas of Switzerlandalso the word “Gout” is used, which means also taste at the same time.

In addition, smelling or odoriferous substances serves organisms for the identification of food, kind comrade and enemies, plays with the social behavior (sex-ripe of females) or with orientation and communication (smell marks) a role.

Humans know thousands ofIdentify to smells and in the memory kept. Smell, the sense of smell for smell perception depend on genetic programs, perception processes and learning in the brain.

Table of contents

procedure of smelling

the smell molecules reach the smelling mucous membrane from air (regio olfactoria). This is in the roof of the nasal cavity and is on each side approx.Piece of cent largely (in former times it was large piece of Pfennig). The smelling cells (primary sensory cells) are in the smelling epithelium and rise up with 5-20 small Zytoplasma - extensions (Stereozilien) in the Mukus, a Schleimschicht, which covers the smelling epithelium. Become the smell receptors, in thatDiaphragm of these cilia find by a smell molecule excited, develops with sufficiently high concentration of the smell molecules a Aktionspotenzial at the axon hill of the smelling cell. This is away-led by the filter plate Lamina cribrosa into the smelling piston. In the smelling piston first and only synaptic interconnecting of the sense of smell finds, beforethe information the appropriate brain centers reach.Mitralzellen take over an integrating over a set of smelling cells, it is common to which that they are excited by the same smell molecules. Each Mitralzelle represents thus a certain smell. From the smelling piston the nerve strands (axons) run now in Tractus olfactorius to the primary olfaktorischen Kortex (brain cortex), to the piriformen Kortex, to the Tuberculum olfactorium and to the Nucleus corticalis the Amygdala. Exist further connections to the hypothalamus and (partially after interconnecting in the mediodorsalen core of the Thalamus) to the orbito frontal Assoziationskortex (seat of the personality)

The smelling function protects the breath organs and the entire organism against harmful influences, e.g. poisonous (usually badly smelling) gases (exception: Carbon monoxide is odorless!). Pleasant smells release secretion reflexes, e.g. „one “with smell after leaking rem meal “the water runs in the mouth together”. On the other hand bad smells nausea can cause. There is thus a close relationship between smell feeling and the unconsciously working part of the nervous system (vegetative nervous system), which all internal functions in the organism steers, e.g. Organ functions, hormone production, entire “feeling “and psychological feeling. Here however smelling has only to a partInfluence on these functions.

Aufgrund der molekularen Vorgänge in den Riechzellen (G-Proteingekoppelte Rezeptoren öffenen TRPM5-Ionenkanäle via ACIII, cAMP hoch -> ) These sensory cells adapt Ca++ influx, depolarization within some minutes (1. CaMKinasen reduce the sensitivity of the channel, 2. Activation of a Ca/Na Antiporters).

The Mukus contains further some enzymes (CYP450), which possibly disturbing molecules during the smell feeling deactivates, as well as transportation proteins, those for a better transportthe smell molecules by the Mukus to the cilia ensure.

It is remarkable that smelling cells regenerate within 60 days from basal cells and old smelling cells go via Apoptose to reason. Basal cells are neural main cells, from whose existence one did not know long time anything.

Smelling pool of broadcasting corporations Axel and Linda bend received to 2004 the Nobelpreis for its work on the sense of smell. see also: olfaktorische perception

of smell organs

all vertebrate animals pronounced smell organs and thus also a more or less developed sense of smell possess. Contrary to air-breathing animals, has itself with constantly in the water living personsAnimals no smell, but a taste feeling develops. Both feelings have many thing in common.Fish have however a clearly trained smell organ, so that one can presuppose a smell feeling with them. Direct observations over it were not made however yet.

Chickens and sparrow-like birds possess a blunt sense of smell, onethe sharper climbing birds, particularly the parrots, the robbery - and water birds. The sump birds have the sharpest sense of smell.

With the best smell perceptions the house dog , the nose of the Dackels possesses possesses about 125 million, those of the Schäferhunds about 220 million smelling sensory cells. Those Smelling mucous membrane of the shepherd dog has a surface of approx. 150 cm ², those of humans approx. 5 cm ² with approximately 5 million smelling sensory cells. Although the shepherd dog possesses 44 times more smelling sensory cells than humans, it can smell thereby about 1 million time better. This could by measurementswith a Olfaktometer to be proven (see. Drö 1984: 108 f.).

With most mammals the smell organ is far more developed than with humans, who must be ranked among the Mikrosmaten.

feeling, Wittern, Flehmen

it gives mammals those feels. Air becomes,in order to follow a trace, purposefully aspirated (proximity effect). These are above all robbery and rodents. Wiederkäuer, Dickhäuter and Einhufer wittern. Smells are transferred by wind currents (action at a distance).

A special development of the smell organ with many mammals permits purposeful Wittern with the mating. This happens through “Flehmen “, either by the nose (hamster, mouse), or by the muzzle (horse, moose) takes place.

The smell feelings can be only heavily described. One differentiates it according to the materials, by which they are caused. They become frequent also afterthese designates.

the smelling mucous membrane a certain humidity, caused in the Schleimdrüsen, must exhibit smell disturbances for the smell feeling. Light catarrhal inflammations of the nose mucous membrane (cold) disturb the smell feeling whole substantially. If one lies on the back, the nasal cavities fill with water. Thusthe smell ability is completely waived. Also with dry nose the smell is strongly reduced.

strength of the smell

the strength smell feeling, caused by different materials is very different. The more highly the concentration of a smelling off in inhaled air, the more strongly is thatFeel. Already an extraordinary small quantity cause a smell feeling. Thus bromine is smelled still in a concentration of 33 mg bromine in 1 m ³ air. Moschus is still noticed, if the nose still less than 1/2.000.000 mg of a wine-mental Moschusextrakts is dargeboten; from hydrogen sulfide becomesstill less than a millionth in air clearly perception. The sense of smell of many animals is still clearly more finely developed. With the duration of a smell impression gradually the smelling mucous membrane fatigues. If we are longer time in a smelling air, then the smell perception finally disappearsfor the steady smell (so-called.phasische Perzeption), without thereby the ability for the perception of other smells decreases. The designation of the smells as pleasant or unpleasantly, which is purely individual and arbitrary, is based partially on conceptions, which refer to the smell feeling. These conceptionschange already with the physiological body conditions. The hungry one z. B. a meal smells extremely pleasantly into the nose, while with the satisfying thereby aversion is excited.

physical definition of the smell

smell is measured by again developed equipment, that the name Rhisometercarries (out altgr. rhis = nose).

The unit of the smell is 1 novel. The unit of the smell is the object smell constant divided by was away in meters.

A list of object smell constants is at present still revised.

The unit of the smell strength certainly by Professor. Dr.Novel cellar, that the coming into co-operation with Professor. Michael Naef developed.

The normal smell humans is with approximately 1 nano novel (in was away from a meter).



to social meanings of the smell

some smells stand in high cultural reputation,e.g.Weihrauch. The production of perfumes is its own industry.

Redensartlich are “smell” - metaphors frequently, if indefinite refusal is expressed, e.g.: I cannot smell it or (anciently) he stand in a bad Ruch. See in addition also Gestank.

physiological measurement

As unit of the smell the Olf was suggested. As a Olf the pollution is indicated, which produces an adult person with 1,8 m ² for skin surface in sitting activity with a hygiene condition of 0,7 baths (every 36 hours a shower/a bath) per day.

See also: Crimp Building syndrome

work on []



  • Cloquet, Osphresiologie or theory of the smells, of the sense of smell etc. (Weimar 1824)
  • Julius amber, the five senses (Leipzig 1875)
  • v. Vintschgau, physiology of the sense of smell (in Hermanns “manual of the physiology”, that. 1880)
  • Chop, a smelling and smell organ (Wiesbaden 1885).


  • Catherine Rouby, Benoist Schaal, Andri Holley, Danihle Dubois, Remi Gervais: Olfaction, key, and Cognition Cambridge University press, 2002, ISBN 0521790581
  • Tim C. Pearce, Susan S. Schiffman, H. Troy et al. Nail (publishers): Handbook OF Machine Olfaction. Electronics Nose Technology, Wiley VCH,2002, ISBN 3527303588
  • Jürgen Raab: Sociology of the smell, Uvk, 2001, ISBN 3896699806
  • Renate Cervinka, Ernst Neudorfer: Psychometri collection of the smelling nuisance. Dangerous materials - keeping clean of air 65 (6), S. 271 - 274 (2005), ISSN 0949-8036
  • Hannah Monyer: In the jungle of the smells in: Ruperto Carola 3/2005(a magazine of the University of Heidelberg)


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