{{Distinguish|Phasmatodea}}{{short description|Nematode anatomical structure}} '''Phasmids''' are sensilla in the lateral tail region of certain species of nematodes.<ref>{{cite web|url=https://faculty.ucr.edu/~pdeley/vce/Nematology159v10/159CD/nervous.htm|title=Nervous System|website=Nematology Through the Virtual Microscope|author1=P. De Ley|author2=I.T. De Ley|author3=L. Mundo|author4=S. Esfahani|author5=M. Mundo|author6=S.A. Nadler|author7=J.G. Baldwin|publisher=University of California Riverside vCenema|year=2000|access-date=5 September 2024}}</ref> They are similar in their structure to amphid sensilla, but smaller.<ref>{{cite journal|last=Schafer|first=William|title=Primer: Nematode nervous systems|journal=Current Biology |issue=20|volume=26|pages=R955–R959|doi=10.1016/j.cub.2016.07.044|doi-access=free|pmid= 27780068|date=24 October 2016}}</ref><ref name=wright1983>{{cite journal|author=K.A. Wright|title=Nematode Chemosensilla: Form and Function|date=April 1983|journal=Journal of Nematology|volume=15|issue=2|pages=151–158|pmid=19295785|pmc=2618269}}</ref>{{rp|154}} One classification system for nematodes places nematodes with phasmids into class Secernentea and nematodes without phasmids into class Adenophorea.<ref name=ohalloranetal2006>{{cite book|last1=O'Halloran|first1=Damien M.|last2=Fitzpatrick|first2=David A.|last3=Burnell|first3=Ann M.|chapter=Chapter 6: The Chemosensory System of ''Caenorhabditis elegans'' and Other Nematodes|title=Chemical Ecology: From Gene to Ecosystem|editor-last1=Dicke|editor-first1=M.|editor-last2=Takken|editor-first2=W.|pages=71–88|publisher=Springer|year=2006|series=Wageningen UR Frontis Series|volume=16|isbn=978-1-4020-4783-1|doi=10.1007/978-1-4020-5369-6_6}}</ref>{{rp|74}} Phasmid neurons were recently shown to function in modulation of chemorepulsion behavior in ''Caenorhabditis elegans''.<ref>{{cite journal|last1=Hilliard|first1=Massimo A.|last2=Bargmann|first2=Cornelia I.|last3=Bazzicalupo|first3=Paolo|title=''C. elegans'' Responds to Chemical Repellents by Integrating Sensory Inputs from the Head and the Tail|journal=Current Biology|year=2002|volume=12|issue=9|pages=730–734|doi=10.1016/S0960-9822(02)00813-8|doi-access=free|pmid=12007416}}</ref> In ''C. elegans'', the right phasmid contains two sensory neurons, while the left contains three, protected by sheath and socket cells. The cilia of the dendrites of the PHA and PHB neurons project through the phasmid openings, while the PQR neuronal process present on the left side is wrapped by a socket cell.<ref name=wright1983/><ref name=ohalloranetal2006/>{{rp|76}}

== References == {{reflist}}

Category:Nematode anatomy

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