Editing Rat (section)

==Rat tails==
[[File:Ratt tail detail.jpg|thumb|A closeup of a rat tail]]
The characteristic long tail of most rodents is a feature that has been extensively studied in various rat species models, which suggest three primary functions of this structure: [[thermoregulation]],<ref>{{cite web |title=Rat Tails |url=http://www.ratbehavior.org/RatTails.htm |website=Rat Behavior and Biology |access-date=30 July 2020}}</ref> minor [[proprioception]], and a [[nocifensive]]-mediated [[degloving]] response.<ref>{{cite web |last1=Grant |first1=Karen |title=Degloving Injury |url=http://ratguide.com/health/trauma/degloving_injury.php |website=Rat Health Guide |access-date=30 July 2020}}</ref> Rodent tails—particularly in rat models—have been implicated with a thermoregulation function that follows from its anatomical construction. This particular tail morphology is evident across the family Muridae, in contrast to the bushier tails of [[Squirrel|Sciuridae]], the squirrel family. The tail is hairless and thin skinned but highly vascularized, thus allowing for efficient [[countercurrent heat exchange]] with the environment. The high [[Muscular tissue|muscular]] and [[connective tissue]] densities of the tail, along with ample muscle attachment sites along its plentiful [[caudal vertebrae]], facilitate specific proprioceptive senses to help orient the rodent in a three-dimensional environment.<ref>{{cite journal | vauthors=Vincent JA, Gabriel HM, Deardorff AS, Nardelli P, Fyffe RE, Burkholder T, Cope TC | journal=Journal of Neurophysiology | title=Muscle proprioceptors in adult rat: mechanosensory signaling and synapse distribution in spinal cord | volume=118 | issue=5 | pages=2687–2701 | date=November 2017 | doi=10.1152/jn.00497.2017 | pmid=28814636 | pmc=5672542 }}</ref> Murids have evolved a unique defense mechanism termed ''degloving'' that allows for escape from predation through the loss of the outermost [[integument]]ary layer on the tail. However, this mechanism is associated with multiple [[pathologies]] that have been the subject of investigation.{{citation needed|date=December 2018}}
[[File:Murid Tail Microscopy Cross Section.jpg|thumb|219x219px|Microscopic cross section of ''Rattus rattus'' tail, delineating tendon bundles, vasculature, and vertebral canal]]
Multiple studies have explored the thermoregulatory capacity of rodent tails by subjecting test organisms to varying levels of physical activity and quantifying [[Thermal conduction|heat conduction]] via the animals' tails. One study demonstrated a significant disparity in [[heat dissipation]] from a rat's tail relative to its abdomen.<ref>{{Cite journal|last=Wanner|first=Samuel|date=2015|title=Thermoregulatory responses in exercising rats: methodological aspects and relevance to human physiology|journal=Temperature|volume=2|issue=4|pages=457–75|doi=10.1080/23328940.2015.1119615|pmid=27227066|pmc=4844073}}</ref> This observation was attributed to the higher proportion of [[vascularity]] in the tail, as well as its higher [[surface-area-to-volume ratio]], which directly relates to heat's ability to dissipate via the skin. These findings were confirmed in a separate study analyzing the relationships of heat storage and [[mechanical efficiency]] in rodents that exercise in warm environments. In this study, the tail was a focal point in measuring heat accumulation and modulation.{{citation needed|date=December 2018}}
 
On the other hand, the tail's ability to function as a proprioceptive sensor and modulator has also been investigated. As aforementioned, the tail demonstrates a high degree of muscularization and subsequent [[innervation]] that ostensibly collaborate in orienting the organism.<ref>{{Cite journal|last=Mackenzie|first=SJ|date=2015|title=Innervation and function of rat tail muscles for modeling cauda equina injury and repair |journal=Muscle and Nerve|volume=52|issue=1|pages=94–102|doi=10.1002/mus.24498|pmid=25346299 }}</ref> Specifically, this is accomplished by coordinated [[flexion]] and extension of tail muscles to produce slight shifts in the organism's [[center of mass]], orientation, etc., which ultimately assists it with achieving a state of proprioceptive balance in its environment. Further mechanobiological investigations of the constituent [[tendon]]s in the tail of the rat have identified multiple factors that influence how the organism navigates its environment with this structure. A particular example is that of a study in which the morphology of these tendons is explicated in detail.<ref>{{Cite journal|last=Bruneau|first=Amelia|date=2010|title=Preparation of Rat Tail Tendons for Biomechanical and Mechanobiological Studies|journal=Journal of Visualized Experiments|volume=41|issue=41|pages=2176|pmc=3156064|pmid=20729800|doi=10.3791/2176}}</ref> Namely, [[Viability assay|cell viability tests]] of tendons of the rat's tail demonstrate a higher proportion of living [[fibroblast]]s that produce the [[collagen]] for these fibers. As in humans, these tendons contain a high density of [[golgi tendon organ]]s that help the animal assess stretching of muscle [[in situ]] and adjust accordingly by relaying the information to higher [[Cerebral cortex|cortical]] areas associated with balance, proprioception, and movement.{{Citation needed|date=December 2018}}
 
The characteristic tail of murids also displays a unique defense mechanism known as ''[[degloving]]'' in which the outer layer of the integument can be detached in order to facilitate the animal's escape from a predator. This evolutionary selective pressure has persisted despite a multitude of [[pathologies]] that can manifest upon [[Shedding (biology)|shedding]] part of the tail and exposing more interior elements to the environment.<ref>{{Cite journal|last=Milcheski|first=Dimas|date=2012|title=Development of an experimental model of degloving injury in rats|journal=Brazilian Journal of Plastic Surgery|volume=27|pages=514–17|doi=10.1590/S1983-51752012000400006 }}</ref> Paramount among these are [[bacteria]]l and [[Virus|viral]] infection, as the high density of [[vascular tissue]] within the tail becomes exposed upon [[Avulsion injury|avulsion]] or similar injury to the structure. The degloving response is a [[wikt:nocifensive|nocifensive]] response, meaning that it occurs when the animal is subjected to [[acute pain]], such as when a predator snatches the organism by the tail.{{citation needed|date=December 2018}}