Olfactory receptor neuron
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218448011
2008-06-10T18:19:50Z
Archelon
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fix broken sentence (assuming 'glomeruli' has not become a verb)
'''{{Infobox_neuron
|neuron_name = Olfactory receptor neuron
|image_neuron = Riechschleimhaut.svg
|caption_neuron = Labels in German. "Zellen" = "[[cell (biology)|cell]]","riech" = "smell", "Riechnerv" = [[olfactory nerve]], "cillien" = [[cilia]].
|location = [[olfactory epithelium]] in the [[nose]]
|function = Detect traces of chemicals in inhaled air ([[olfaction|sense of smell]])
|neurotransmitter = [[Glutamate]]
|morphology = Bipolar sensory receptor
|afferents = None
|efferents = [[Olfactory bulb]]
|GraySubject = 223
|GrayPage = 996
}}
[[Image:Gray772.png|thumb|right|200px|Plan of olfactory neurons.]]
An '''olfactory receptor neuron,''' also called an '''olfactory sensory neuron,''' is the primary [[transduction (physiology)|transduction]] cell in the [[olfactory system]].
==In vertebrates==
Humans have about 40 million olfactory receptor neurons. In vertebrates, olfactory receptor neurons reside on the [[olfactory epithelium]] in the [[nasal cavity]]. These cells are bipolar [[neuron]]s with a [[dendrite]] facing the interior space of the nasal cavity and an [[axon]] that travels along the [[olfactory nerve]] to the [[olfactory bulb]].
===Structure===
Many tiny hair-like [[cilia]] protrude from the olfactory receptor cell's dendrite into the [[mucus]] covering the surface of the olfactory epithelium. The surface of these cilia is covered with [[olfactory receptor]]s, a type of [[G protein-coupled receptor]]. Each olfactory receptor cell [[Gene expression|expresses]] only one type of olfactory receptor, but many separate olfactory receptor cells express olfactory receptors which bind the same set of odors. The axons of olfactory receptor cells which bind the same odors converge to form [[glomerulus (olfaction)|glomeruli]] in the [[olfactory bulb]].
===Function===
A given olfactory receptor can bind to a variety of odor molecules with varying affinities. The activated olfactory receptor in turn activates the intracellular G-protein GOLF ({{Gene|GNAL}}), and [[adenylate cyclase]] and production of [[Cyclic AMP]] opens [[ion channel]]s in the [[cell membrane]], resulting in an influx of [[sodium]] and [[calcium]] ions into the cell. This influx of positive ions causes the neuron to depolarize, generating an [[action potential]].
===Regeneration ===
Individual olfactory receptor neurons are replaced approximately every 40 days by [[neural stem cell]]s residing in the olfactory epithelium. The regeneration of olfactory receptor cells, as one of the only few instances of adult [[neurogenesis]] in the [[central nervous system]], has raised considerable interest in dissecting the pathways for neural development and differentiation in adult organisms.
==In insects==
In [[insect]]s, olfactory receptor neurons typically reside on the [[antenna (biology)|antenna]]. Much like in vertebrates, axons from the sensory neurons converge into glomeruli in the [[antennal lobe]].
==See also==
* [[Chemoreceptor]]
* [[Sensory receptor]]
==External links==
* {{eMedicineDictionary|olfactory+receptor+cells}}
* {{Dorlands|c_18|12224417}}
{{Olfactory_system}}
{{Nervous tissue}}
[[Category:Chemoreceptor cells]]
[[category:Olfactory system]]
[[Category:Neurons]]
[[Category:Signal transduction]]
[[de:Riechschleimhaut]]
[[ja:嗅覚受容神経]]