olfactory nerve

(redirected from CN I)
Also found in: Dictionary, Thesaurus, Legal, Encyclopedia, Wikipedia.
Related to CN I: Cranial nerves, trigeminal nerve, CN V

olfactory

 [ol-fak´tŏ-re]
pertaining to smell.
olfactory nerve the first cranial nerve; it is purely sensory and is concerned with the sense of smell. The nerve cell bodies are situated in the olfactory area of the mucous membrane of the nose. The nerve fibers lead upward through openings in the ethmoid bone, connect with the cells of the olfactory bulb, and then pass inward to the cerebrum. See Appendix 2-5.

olfactory nerve

n.
Either of the first pair of cranial nerves that conduct impulses from the mucous membranes of the nose to the olfactory bulb.

olfactory nerve

one of a pair of nerves associated with the sense of smell. They are composed of numerous fine filaments that ramify in the mucous membrane of the olfactory area. The fibers of the olfactory nerve are nonmedullated and unite into fasciculi that form a plexus under the mucous membrane and rise in grooves or canals in the ethmoid bone. The fibers pass into the skull and form synapses with the dendrites of the mitral cells. The area in which the olfactory nerves arise is situated in the most superior part of the mucous membrane that covers the superior nasal concha. The olfactory sensory endings are modified epithelial cells and the least specialized of the special senses. The olfactory nerves connect with the olfactory bulb and the olfactory tract, which are components of the part of the brain associated with the sense of smell. Also called first cranial nerve, nervus olfactorius.
enlarge picture
Olfactory nerve
Enlarge picture
RIGHT OLFACTORY NERVE

olfactory nerve

A sensory nerve with neuronal cell bodies located in the olfactory epithelium (a yellowish-brown thickened patch of epithelium found along the upper back walls of the nasal cavity). Axons from the receptor cells join into approximately 20 small nonmyelinated bundles (the olfactory nerves). These nerves pass into the skull through holes in the cribriform plate of the ethmoid bone and terminate in the ipsilateral olfactory bulb in spherical synaptic structures called glomeruli.
Synonym: first cranial nerve See: cranial nerveillustration
See also: nerve

olfactory nerve,

n first cranial nerve. See nerve, olfactory. See odor.

olfactory

pertaining to the sense of smell.

olfactory bulb
the bulblike extremity of the olfactory tract on the rostral surface of the frontal lobe of each cerebral hemisphere; it is lodged against the cribriform plate through which the olfactory nerves pass.
olfactory glands
in the mucosa of the nasal olfactory region; branched tubuloalveolar glands secreting serous fluid; cleanse the mucosal surface, dissolve odor-producing substances.
olfactory hair
modified cilia projecting from olfactory cells in the mucosa of the nasal olfactory area.
olfactory mucosa
specialized olfactory cells in a region of nasal mucosa covering ethmoturbinates, turbinates and nasal septum.
olfactory nerve
the first cranial nerve made up of about 20 bundles and concerned with the sense of smell. The cell bodies are situated in the olfactory mucous membrane of the nose. Nerve fibers lead upward through openings in the cribriform plate of the ethmoid bone and connect with the cells of the olfactory bulb. From there the fibers pass inward to the cerebrum. See also Table 14.
olfactory neuroblastoma
rare neoplasm, commonest in pups and kittens, characterized by local invasion of surrounding bone.
olfactory pit
primordia of the nasal cavities commencing as pits in the olfactory placodes of the embryo. The pits deepen and finally open into the oral cavity as the choanae; the external orifices become the nostrils. Called also nasal pit.
olfactory system
includes the olfactory part of the nasal mucosa, the olfactory nerves and the olfactory bulbs of the cerebrum.
olfactory tract
a band of white nerve fibers visible on the ventral surface of the brain running caudally from the olfactory bulbs.
olfactory tractotomy
surgical removal or transection of the olfactory tracts to produce an anosmia may be performed in cats as a means of controlling spraying and inappropriate urination.