Olfactory nerve
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220250161
2008-06-18T23:32:08Z
Eeekster
5583074
Reverted edits by [[Special:Contributions/68.192.77.22|68.192.77.22]] ([[User talk:68.192.77.22|talk]]) to last version by ClueBot
{{Infobox Nerve |
Name = {{PAGENAME}} |
Latin = nervus olfactorius |
GraySubject = 196 |
Image = Gray771.png |
Caption = |
Innervates = |
BranchFrom = |
BranchTo = |
MeshName = Olfactory+Nerve |
MeshNumber = A08.800.800.120.640 |
}}
The '''olfactory nerve''', or '''cranial nerve I''', is the first of twelve [[cranial nerve]]s. The specialized [[olfactory receptor neuron]]s of the olfactory nerve are located in the olfactory [[mucosa]] of the upper parts of the [[nasal cavity]]. The olfactory nerves do not form two trunks like the remaining cranial nerves, but consist of a collection of many sensory nerve fibers that extend from the olfactory epithelium to the [[olfactory bulb]], passing through the many openings of the Cribriform plate of the Ethmoid bone; a [[sieve]]-like structure.
[[Olfactory receptor neuron]]s continue to be born throughout life and extend new axons to the [[olfactory bulb]]. Olfactory ensheathing glia wrap bundles of these axons and are thought to facilitate their passage into the central nervous system.
The sense of [[olfaction|smell]] (olfaction) arises from the stimulation of the olfactory receptors by activation from gas molecules that pass by the nose during respiration. The resulting electrical activity is [[transduction (physiology)|transduced]] into the olfactory bulb which then transmits the electrical activity to other parts of the [[olfactory system]] and the rest of the [[central nervous system]] via the olfactory tract.
The olfactory nerve is the shortest of all the twelve cranial nerves and only one of two cranial nerves (the other being the [[optic nerve]]) that do not join with the [[brainstem]].
==Testing the Olfactory nerve==
To test the function of the olfactory nerve, doctors block one of the patient's nostrils and place a pungent odor (such as damp coffee essence) under the open nostril. The test is then repeated on the other nostril.
==Lesions of the Olfactory nerve==
Lesions to the Olfactory nerve often lead to a reduced ability to taste and smell. However, ammonia can still be detected by the pain fibers of the Trigeminal nerve. They can occur because of blunt trauma, such a coup-contra-coup damage, meningitis and tumors of the frontal lobe.
==Additional images==
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==See also==
* [[Anterior olfactory nucleus]]
==External links==
* {{YaleCranialNerves|1|1}}
* {{NormanAnatomy|cranialnerves}} ({{NormanAnatomyFig|I}})
{{Cranial nerves}}
{{Olfactory_system}}
[[Category:Central nervous system]]
[[Category:Olfactory system]]
[[Category:Cranial nerves]]
[[ar:عصب شمي]]
[[de:Nervus olfactorius]]
[[fr:Nerf olfactif]]
[[hr:Njušni živci]]
[[it:Nervo olfattivo]]
[[lt:Uoslės nervas]]
[[nl:Nervus olfactorius]]
[[ja:嗅神経]]
[[no:Nervus olfactorius]]
[[pl:Nerw węchowy]]
[[pt:Nervo olfatório]]
[[fi:Hajuhermo]]
[[th:เส้นประสาทรับกลิ่น]]
[[zh:嗅神經]]