Editing Statocyst

{{Short description|Balancing organ in certain aquatic invertebrate animals}}
[[File:Statocyst.jpg|thumb|right|alt=|Drawing of the statocyst system]]
[[File:Gigantopelta chessoia statocysts.png|thumb|Statocysts (ss) and statolith (sl) inside the head of sea snail ''[[Gigantopelta chessoia]]'']]

The '''statocyst''' is a [[Equilibrioception|balance sensory receptor]] present in some aquatic [[invertebrate]]s, including [[bivalve]]s,<ref>{{Cite journal | last1 = Morton | first1 = B. | doi = 10.1111/j.1469-7998.1985.tb05633.x | title = Statocyst structure in the Anomalodesmata (Bivalvia) | journal = Journal of Zoology | volume = 206 | pages = 23–34 | year = 2009 }}</ref> [[cnidaria]]ns,<ref>{{Cite journal | last1 = Spangenberg | first1 = D. B. | title = Statolith formation in Cnidaria: effects of cadmium on ''Aurelia'' statoliths | journal = Scanning Electron Microscopy | issue = 4 | pages = 1609–1618
| year = 1986 | pmid = 11539690}}</ref> [[ctenophora]]ns,<ref>{{Cite journal | last1 = Lowe | first1 = B. | title = The role of Ca2+ in deflection-induced excitation of motile, mechanoresponsive balancer cilia in the ctenophore statocyst. | journal = Journal of Experimental Biology | volume = 200| pages = 1593–1606 | year = 1997| issue = Pt 11 | doi = 10.1242/jeb.200.11.1593 | pmid = 9202448 | bibcode = 1997JExpB.200.1593L }}</ref> [[echinoderm]]s,<ref>{{Cite journal | last1 = Ehlers | first1 = U. | doi = 10.1111/j.1463-6395.1997.tb01127.x | title = Ultrastructure of the statocysts in the apodous sea cucumber ''Leptosynapta inhaerens'' (Holothuroidea, Echinodermata) | journal = Acta Zoologica | volume = 78 | pages = 61–68 | year = 1997 }}</ref> [[cephalopod]]s,<ref>{{Cite journal | last1 = Clarke | first1 = M. R. | title = The cephalopod statolithan—introduction to its form | doi = 10.1017/S0025315400041345 | journal = Journal of the Marine Biological Association of the United Kingdom | volume = 58 | issue = 3 | pages = 701–712| year = 2009 }}</ref><ref>{{Cite journal | last1 = Levi | first1 = R.  | last2 = Varona | first2 = P.  | last3 = Arshavsky | first3 = Y. I.  | last4 =  Rabinovich | first4 = M. I.   | last5 = Selverston | first5 = A. I.   | doi = 10.1152/jn.00753.2003 | title = Dual Sensory-Motor Function for a Molluskan Statocyst Network | journal = Journal of Neurophysiology | volume = 91 | issue = 1 | pages = 336–345 | year = 2004| pmid = 14507988 }}</ref>  [[crustacean]]s,<ref>{{Cite journal | last1 = Cohen | first1 = M. J. | title = The response patterns of single receptors in the crustacean statocyst | doi = 10.1098/rspb.1960.0020 | journal = Proceedings of the Royal Society B: Biological Sciences | volume = 152 | issue = 946 | pages = 30–49 | year = 1960 | pmid =  13849418| bibcode = 1960RSPSB.152...30C | s2cid = 29494854 }}</ref> and [[gastropods]],<ref name="Deliagina Arshavsky Orlovsky 1998 pp. 172–175">{{cite journal |last1=Deliagina |first1=Tatiana G. |last2=Arshavsky |first2=Yuri I. |last3=Orlovsky |first3=Grigori N. |date=1998 |title=Control of spatial orientation in a mollusc |journal=Nature |volume=393 |issue=6681 |pages=172–175 |doi=10.1038/30251 |pmid=9603520 |bibcode=1998Natur.393..172D |issn=0028-0836}}</ref> A similar structure is also found in ''[[Xenoturbella]]''.<ref>{{Cite journal | last1 = Israelsson | first1 = O. | title = Ultrastructural aspects of the 'statocyst' of ''Xenoturbella'' (Deuterostomia) cast doubt on its function as a georeceptor | doi = 10.1016/j.tice.2007.03.002 | journal = Tissue and Cell | volume = 39 | issue = 3 | pages = 171–177 | year = 2007 | pmid =  17434196}}</ref> The statocyst consists of a sac-like structure containing a mineralised mass ('''statolith''') and numerous innervated sensory hairs ([[seta]]e). The statolith's [[inertia]] causes it to push against the setae when the animal accelerates.  Deflection of setae by the statolith in response to [[gravity]] activates [[neuron]]s, providing feedback to the animal on change in orientation and allowing balance to be maintained.

In other words, the statolith shifts as the animal moves. Any movement large enough to throw the organism off balance causes the statolith to brush against tiny bristles which in turn send a message to the brain to correct its balance.

It may have been present in the common ancestor of cnidarians and bilaterians.{{citation needed|date=June 2022}}

==Hearing==

In [[cephalopod]]s like [[squid]]s, statocysts provide a [[cochlea]]-like mechanism to [[Hearing|hear]].<ref>{{Cite web|url=http://www.whoi.edu/oceanus/feature/scientists-find-that-squid-can-detect-sounds|title = Scientists Find that Squid Can Detect Sounds}}</ref><ref>{{Cite web|url=https://www.livescience.com/11707-squid-hear-itos-motion-ocean.html|title = How Squid Hear: It's All in the Motion of the Ocean| website=[[Live Science]] |date = 2 February 2011}}</ref> As a result, the [[longfin inshore squid]] for instance can hear low-frequency sounds between 30 and 500 [[Hz]] when the water temperature is above {{Cvt|8|C}}.<ref>{{Cite web|url=https://phys.org/news/2011-02-squid-shown.html|title = Squid shown to be able to hear}}</ref>

==See also==
*[[Accelerometer]]
*[[Inertial guidance]]
*[[Müllerian vesicle]], similar structure in [[Loxodidae|loxodid ciliates]]
*[[Otolith]], an equivalent structure in vertebrates.
*[[Statocyte]], a similar structure in plants
*[[Sensory organs of gastropods]]

==References==
{{reflist}}

{{Cephalopod anatomy}}

[[Category:Vestibular system]]
[[Category:Cnidarian anatomy]]
[[Category:Arthropod anatomy]]
[[Category:Mollusc anatomy]]