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Rhinophore

A rhinophore is one of a pair of chemosensory club-shaped, rod-shaped or ear-like structures which are the most prominent part of the external head anatomy in sea slugs, marine gastropod opisthobranch mollusks such as the nudibranchs, sea hares (Aplysiomorpha), and sap-sucking sea slugs (Sacoglossa).

A pair of rhinophores on the head of Goniobranchus coi
Right rhinophore of Acanthodoris pilosa

Etymology edit

The name relates to the rhinophore's function as an organ of "smell". Rhino- means nose from Ancient Greek ῥίς rhis and from its genitive ῥινός rhinos. "Phore" means "to bear" from Neo-Latin -phorus and from Greek -phoros (φορος) "bearing", a derivative of phérein (φέρειν).

Function edit

Rhinophores are scent or taste receptors, also known as chemosensory organs situated on the dorsal surface of the head. They are primarily used for distance chemoreception and rheoreception (response to water current).[1]

The "scents" detected by rhinophores are chemicals dissolved in the sea water. The fine structure and hairs of the rhinophore provide a large surface area so that chemical detection is maximized.[2] This allows the nudibranchs to stay close to their food source (for example species of sponges) and to find mates. In the sea hare Aplysia californica, the rhinophores are able to detect pheromones.[1]

Protection edit

To protect the prominent rhinophores against nibbling by predators, including fish, most species of dorid nudibranchs are able to withdraw their rhinophores into a pocket beneath the skin.[2]

Structure edit

 
Rhinophores of Aplysia californica

In reproductively mature Aplysia adults, the rhinophore is about 1 cm in length.[1] The neuroanatomical organization includes a rhinophore groove where most of the sensory cells appear to be concentrated. Its sensory epithelium contains sensory neurons that project axons back to rhinophore ganglia and dendrites that end in either a surface-exposed cilium or a small protuberance.[1]

 
A low-power scanning electron microscopy (SEM) micrograph showing the rhinophore tip of Aplysia californica
Scale bar is 300 μm.
rg - rhinophore groove
tip - rhinophore tip.
 
A medium-power SEM image showing the cilia-bearing epithelium within the rhinophore groove
Scale bar is 100 μm.
f - folds
 
A high-power SEM image showing cilia extending from a common pore: Also evident are pores lacking obvious bunched cilia.
Scale bar is 10 μm.
ci - numerous long cilia

Comparison with oral tentacles edit

In A. californica, the oral tentacles, which are situated in a more ventral position, are possibly involved in contact chemoreception and mechanoreception.[1]

References edit

This article incorporates CC-BY-2.0 text (but not under GFDL) from reference.[1]

  1. ^ a b c d e f Scott F Cummins, Dirk Erpenbeck, Zhihua Zou, Charles Claudianos, Leonid L Moroz, Gregg T Nagle & Bernard M Degnan. 2009. Candidate chemoreceptor subfamilies differentially expressed in the chemosensory organs of the mollusc Aplysia. BMC Biology 2009, 7:28. doi:10.1186/1741-7007-7-28.
  2. ^ a b Rhinophore in nudibranchs 2007-10-21 at the Wayback Machine. Sea Slug Forum, accessed 8 July 2009.

Further reading edit

  • Wertz A., Rössler W., Obermayer M. & Bickmeyer U. (6 April 2006) "Functional neuroanatomy of the rhinophore of Aplysia punctata". Frontiers in Zoology 3: 6. doi:10.1186/1742-9994-3-6

rhinophore, rhinophore, pair, chemosensory, club, shaped, shaped, like, structures, which, most, prominent, part, external, head, anatomy, slugs, marine, gastropod, opisthobranch, mollusks, such, nudibranchs, hares, aplysiomorpha, sucking, slugs, sacoglossa, p. A rhinophore is one of a pair of chemosensory club shaped rod shaped or ear like structures which are the most prominent part of the external head anatomy in sea slugs marine gastropod opisthobranch mollusks such as the nudibranchs sea hares Aplysiomorpha and sap sucking sea slugs Sacoglossa A pair of rhinophores on the head of Goniobranchus coiRight rhinophore of Acanthodoris pilosa Contents 1 Etymology 2 Function 3 Protection 4 Structure 5 Comparison with oral tentacles 6 References 7 Further readingEtymology editThe name relates to the rhinophore s function as an organ of smell Rhino means nose from Ancient Greek ῥis rhis and from its genitive ῥinos rhinos Phore means to bear from Neo Latin phorus and from Greek phoros foros bearing a derivative of pherein ferein Function editMain article Sensory organs of gastropods Rhinophores are scent or taste receptors also known as chemosensory organs situated on the dorsal surface of the head They are primarily used for distance chemoreception and rheoreception response to water current 1 The scents detected by rhinophores are chemicals dissolved in the sea water The fine structure and hairs of the rhinophore provide a large surface area so that chemical detection is maximized 2 This allows the nudibranchs to stay close to their food source for example species of sponges and to find mates In the sea hare Aplysia californica the rhinophores are able to detect pheromones 1 Protection editTo protect the prominent rhinophores against nibbling by predators including fish most species of dorid nudibranchs are able to withdraw their rhinophores into a pocket beneath the skin 2 Structure edit nbsp Rhinophores of Aplysia californicaIn reproductively mature Aplysia adults the rhinophore is about 1 cm in length 1 The neuroanatomical organization includes a rhinophore groove where most of the sensory cells appear to be concentrated Its sensory epithelium contains sensory neurons that project axons back to rhinophore ganglia and dendrites that end in either a surface exposed cilium or a small protuberance 1 nbsp A low power scanning electron microscopy SEM micrograph showing the rhinophore tip of Aplysia californicaScale bar is 300 mm rg rhinophore groovetip rhinophore tip nbsp A medium power SEM image showing the cilia bearing epithelium within the rhinophore grooveScale bar is 100 mm f folds nbsp A high power SEM image showing cilia extending from a common pore Also evident are pores lacking obvious bunched cilia Scale bar is 10 mm ci numerous long ciliaComparison with oral tentacles editIn A californica the oral tentacles which are situated in a more ventral position are possibly involved in contact chemoreception and mechanoreception 1 References editThis article incorporates CC BY 2 0 text but not under GFDL from reference 1 a b c d e f Scott F Cummins Dirk Erpenbeck Zhihua Zou Charles Claudianos Leonid L Moroz Gregg T Nagle amp Bernard M Degnan 2009 Candidate chemoreceptor subfamilies differentially expressed in the chemosensory organs of the mollusc Aplysia BMC Biology 2009 7 28 doi 10 1186 1741 7007 7 28 a b Rhinophore in nudibranchs Archived 2007 10 21 at the Wayback Machine Sea Slug Forum accessed 8 July 2009 Further reading editWertz A Rossler W Obermayer M amp Bickmeyer U 6 April 2006 Functional neuroanatomy of the rhinophore of Aplysia punctata Frontiers in Zoology 3 6 doi 10 1186 1742 9994 3 6 nbsp Wikimedia Commons has media related to Rhinophores Retrieved from https en wikipedia org w index php title Rhinophore amp oldid 1153679022, wikipedia, wiki, book, books, library,

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