olfactory organ

Thesaurus

Noun

olfactory organ - the organ of smell and entrance to the respiratory tract; the prominent part of the face of man or other mammals; "he has a cold in the nose"noseneb, snout - a long projecting or anterior elongation of an animal's head; especially the noserostrum, snout - beaklike projection of the anterior part of the head of certain insects such as e.g. weevilsturbinal, turbinate, turbinate bone - any of the scrolled spongy bones of the nasal passages in man and other vertebrateschemoreceptor - a sensory receptor that responds to chemical stimuliarteria ethmoidalis, ethmoidal artery - a branch of the ophthalmic artery supplying structures in and around the nasal capsuleupper respiratory tract - the nose and throat and tracheanasal cavity - either of the two cavities lying between the floor of the cranium and the roof of the mouth and extending from the face to the pharynxinternasal suture, sutura internasalis - the suture between the two nasal boneshooter, schnoz, schnozzle, snoot, snout, nozzle, honker, beak - informal terms for the noseconk - informal term for the nosehawk nose - a nose curved downward like the beak of a hawkproboscis - the human nose (especially when it is large)bridge - the hard ridge that forms the upper part of the nose; "her glasses left marks on the bridge of her nose"pug nose - a short nose; flattened and turned up at the endhooknose, Roman nose - a nose with a prominent slightly aquiline bridgeanterior naris, nostril - either one of the two external openings to the nasal cavity in the noseface, human face - the front of the human head from the forehead to the chin and ear to ear; "he washed his face"; "I wish I had seen the look on his face when he got the news"

Olfactory Organ

olfactory organ

[äl′fak·trē ‚ȯr·gən] (physiology) Any of the small chemoreceptors in the mucous membrane lining the upper part of the nasal gravity which receive stimuli interpreted as odors.

Olfactory Organ

the organ in man and animals that receives chemical stimuli that are interpreted as smells. The sense of smell is technically known as olfaction.

In man the olfactory organ is the superoposterior area of the nasal cavity, including part of the nasal septum and the two turbinate bones, which protrude from the lateral walls of the cavity. The entire olfactory organ is covered by the olfactory epithelium, whose surface area is about 5 cm². In many macros-matics—mammals with highly developed olfaction—the olfactory area of the nose is enlarged because of the presence of supplementary turbinate bones in the bony wall of the nasal cavity. In reptiles and some mammals the nasal septum contains the vomeronasal organ, or Jacobson’s organ, in addition to the principal olfactory organs. In fish the olfactory organs are represented by paired nasal depressions or by nasal pouches, which are located on the head adjacent to the mouth. These olfactory organs include numerous connective-tissue membranes that are covered with olfactory epithelium. In insects the olfactory sen-silla—sensitive structures that are located mainly on the antennae—serve as olfactory organs. In a number of mollusks the osphradia serve as olfactory organs.

The spindle-shaped olfactory receptor cells, which are located in the olfactory organs, are the functional units of the olfactory apparatus. The rabbit has about 100 million such cells; man, about 10 million; and the male silkworm, about 40,000. Two outgrowths emerge from each olfactory receptor cell. The long, thin central outgrowth joins with the olfactory nerve; the second outgrowth extends to an external surface of the olfactory organ. In vertebrates the second outgrowth surfaces on the olfactory epithelium with a club-shaped thickening. Bundles of flagella that are from 0.25 to 0.3 microns thick and a few tenths of a micron long extend from these thickenings. In birds and reptiles the olfactory receptors are also equipped with short, finger-like outgrowths called microvilli.

In the olfactory sensilla of insects, each receptor cell has one flagellum. Outgrowths extend from each flagellum toward openings in the cuticle, which is the external protective layer of epidermis that covers the sensilla. In terrestrial and aquatic vertebrates and in insects the olfactory flagella are immersed in mucus that is secreted by glandular cells. This mucus is the interstitial medium into which molecules of odorous substances enter from the air or from water. It is assumed that the initial interaction of the receptor cells with the molecules of odorous substances occurs in the flagella of the olfactory receptors.

REFERENCES

Vinnikov, la. A., and L. K. Titova. Morfologiia organa obonianiia. Moscow, 1957.
Ivanov, V. P. “Ul’trastrukturnaia organizatsiia khemoretseptorov nasekomykh.” Trudy Vsesoiuznogo entomologicheskogo obshchestva, 1969, vol. 53.
Bronshtein, A. A. “Strukturnaia organizatsiia perifericheskikh otdelov oboniatel’nogo analizatora i oboniatel’noi lukovitsy.” In Fiziologiia sensornykh sistem, part 2. Leningrad, 1972.

A. V. MINOR

olfactory organ

Olfactory Organ

olfactory organ

Olfactory Organ

REFERENCES

olfactory organ

olfactory neuroepithelium

olfactory organ

Synonyms for olfactory organ

noun the organ of smell and entrance to the respiratory tract

Synonyms

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