Editing Lateral line (section)

== Anatomy ==

[[File:LateralLine Organ.jpg|thumb|center|upright=3|The lateral line system consists of canals that run along a fish's body, connecting rows of openings (pores) through the skin and scales to the water outside the body. Small sense organs, neuromasts (inset), are positioned both at intervals along the canals, and on the surface of the body. Each hair cell contains a bundle of sensory hairs.]]
<!--[[File:RutilusRutilusScalesLateralLine.JPG|thumb|Some scales of the lateral line of a ''[[Rutilus rutilus]]'']]-->

[[File:Gasterosteus aculeatus with stained neuromasts.png|thumb|A [[Gasterosteus aculeatus|three-spined stickleback]] with stained neuromasts<ref>{{cite journal |last1=Wark |first1=Abigail R. |last2=Mills |first2=Margaret G. |last3=Dang |first3=Lam-Ha |last4=Chan |first4=Yingguang Frank |last5=Jones |first5=Felicity C |last6=Brady |first6=Shannon D. |last7=Absher |first7=Devin M |last8=Grimwood |first8=Jane |last9=Schmutz |first9=Jeremy |last10=Myers |first10=Richard M. |last11=Kingsley |first11=David M. |last12=Peichel |first12=Catherine L. |display-authors=3 |year=2012 |title=Genetic Architecture of Variation in the Lateral Line Sensory System of Threespine Sticklebacks |journal=G3: Genes, Genomes, Genetics |volume=2 |issue=9 |pages=1047–1056 |doi=10.1534/g3.112.003079 |pmid=22973542 |pmc=3429919 }}</ref>]]

Lateral lines are usually visible as faint lines of pores running along each side of a fish's body.<ref name="Bleckmann Zelick 2009"/> The functional units of the lateral line are the neuromasts, discrete [[mechanoreception|mechanoreceptive]] organs that sense movement in water. There are two main varieties: canal neuromasts and superficial neuromasts. Superficial neuromasts are on the surface of the body, while canal neuromasts are along the lateral lines in subdermal, fluid-filled canals. Each neuromast consists of receptive [[hair cells]] whose tips are covered by a flexible jellylike cupula. Hair cells typically possess both [[glutamatergic]] [[afferent nerve fiber|afferent connections]] and [[acetylcholine|cholinergic]] [[efferent nerve fiber|efferent connections]].<ref>{{cite journal |last1=Russell |first1=I. J. |year=1971 |title=The Pharmacology of Efferent Synapses in the Lateral-Line System of Xenopus Laevis |journal=Journal of Experimental Biology |volume=54 |issue=3 |pages=643–659 |doi=10.1242/jeb.54.3.643 |pmid=4326222 |doi-access= |bibcode=1971JExpB..54..643R }}</ref><ref name="Flock 1967"/> The receptive hair cells are modified [[epithelial cells]]; they typically possess bundles of 40–50 [[microvilli]] "hairs" which function as the mechanoreceptors.<ref name="Flock 1967">{{cite book |last=Flock |first=Å. |year=1967 |chapter=Ultrastructure and function in the lateral line organs |title=Lateral Line Detectors; proceedings of a conference held at Yeshiva University, New York, April 16-18, 1966 |editor=P. Cahn |publisher=[[Indiana University Press]] |pages=163–197 }}</ref> Within each bundle, the hairs are organized in a rough "staircase" from shortest to longest.<ref name="Peach">{{cite journal |last1=Peach |first1=M. B. |last2=Rouse |first2=G. W. |year=2000 |title=The Morphology of the Pit Organs and Lateral Line Canal Neuromasts of ''Mustelus Antarcticus'' (Chondrichthyes: Triakidae) |journal=Journal of the Marine Biological Association of the United Kingdom |volume=80 |issue=1 |pages=155–162 |doi=10.1017/s0025315499001678 |bibcode=2000JMBUK..80..155P |s2cid=85963954 }}</ref>{{-}}