Reflex 381186 226002172 2008-07-16T11:49:47Z Thijs!bot 1392310 robot Adding: [[id:Refleks]] {{for|the novel|reflex (novel)}} A '''reflex action''' is involuntary and almost instant movement in response to [[stimulus]].<ref>Purves (2004). ''Neuroscience: Third Edition''. Massachusetts, Sinauer Associates, Inc. </ref> In most contexts, especially involving humans, a reflex action is mediated via the [[reflex arc]] (although this is not always true in other animals, or in more casual usage of the term 'reflex'.) Reflexes are tested as part of a [[neurological examination]] to assess damage to or functioning of the [[Central nervous system|central]] and [[peripheral nervous system]]. Reflexes may be trained, such as during repetition of motor actions during sport practice, or the linking of stimuli with [[Autonomic nervous system|autonomic reactions]] during [[classical conditioning]]. ==Reaction time== For a reflex, [[reaction time]] or latency is the time from the onset of a stimulus until the [[organism]] responds. In [[animals]], reaction time to [[Visual perception|visual]] stimuli is typically 150 to 300 [[millisecond]]s.<ref>{{cite web | url = http://www.humanbenchmark.com/tests/reactiontime/stats.php | accessdate = 2007-10-11 | title = Human Benchmark: Reaction Time Statistics }}</ref> ==Human reflexes== [[Image:ReflexArc1.jpg|right|thumb|300px|The mechanism of the [[reflex arc]]. Note that this image includes an [[interneuron]] in the monosynaptic [[patellar reflex]] for purposes of illustration.]] Reflex actions include: ===Tendon reflexes=== The deep [[tendon reflex]]es provide information on the integrity of the central and peripheral nervous system. Generally, decreased reflexes indicate a peripheral problem, and lively or exaggerated reflexes a central one. * [[Biceps reflex]] ([[cervical spinal nerve 5|C5]], [[cervical spinal nerve 6|C6]]) * [[Brachioradialis reflex]] (C5, C6, [[cervical spinal nerve 7|C7]]) * [[Extensor digitorum reflex]] (C6, C7) * [[Triceps reflex]] (C6, C7, [[cervical spinal nerve 8|C8]]) * [[Patellar reflex]] or knee-jerk reflex ([[lumbar spinal nerve 2|L2]], [[lumbar spinal nerve 3|L3]], [[lumbar spinal nerve 4|L4]]) * [[Ankle jerk reflex]] (Achilles reflex) ([[sacral spinal nerve 1|S1]], [[sacral spinal nerve 2|S2]]) * [[Plantar reflex]] or Babinski reflex ([[lumbar spinal nerve 5|L5]], S1, S2) While the reflexes above are stimulated mechanically, the term [[H-reflex]] refers to the analogous reflex stimulated electrically, and [[Tonic vibration reflex]] for those stimulated by vibration. ===Reflexes involving cranial nerves=== {| class="wikitable" | '''Name''' || '''Sensory''' || '''Motor''' |- | [[Pupillary reflex]] || II || III |- | [[Accommodation reflex]] || II || III |- | [[Jaw jerk reflex]] || V || V |- | [[Corneal reflex]], also known as the [[blink]] reflex || V || VII |- | [[Caloric reflex test]]/[[Vestibulo-ocular reflex]] || VIII || III, IV, VI + |- | [[Gag reflex]] || IX || X |} ===Reflexes in infants only=== {{main|Primitive reflexes}} [[Image:Greifreflex.JPG|thumb|Grasp reflex ]] [[Newborn babies]] have a number of other reflexes which are not seen in adults, referred to as '''primitive reflexes'''.<ref>http://www.fpnotebook.com/Neuro/Exam/NrlgcExm.htm</ref> These include: * [[Asymmetrical tonic neck reflex]] (ATNR) * [[Grasp reflex]] * [[Hand-to-mouth reflex]] * [[Moro reflex]], also known as the startle reflex * [[Sucking]] * Symmetrical tonic neck reflex (STNR) * [[Tonic labyrinthine reflex]] (TLR) ===Other reflexes=== Other reflexes found in the human nervous system include: * [[Anal wink|Anocutaneous reflex]] * [[Bulbocavernosus reflex]] * [[Escape reflex]] * [[Mammalian diving reflex]] * [[Oculocardiac reflex]] * [[Optokinetic reflex]] * [[Photic sneeze reflex]] * [[Scratch reflex]] * [[Withdrawal reflex]] **[[Crossed extensor reflex]] * [[Muscular defense]] Processes such as [[breath]]ing, [[digestion]], and the maintenance of the [[Heart rate|heartbeat]] can also be regarded as reflex actions, according to some definitions of the term. ==See also== *[[Automatic behavior]] *[[Voluntary action]] ==References== {{reflist}} {{Nervous system physiology}} {{Reflex}} [[Category:Reflexes]] [[ca:Reacció reflexa]] [[cs:Reflex]] [[da:Refleks]] [[de:Reflex]] [[et:Refleks]] [[es:Reflejo]] [[eo:Reflekso]] [[fr:Réflexe (réaction motrice)]] [[gl:Reacción reflexa]] [[id:Refleks]] [[it:Riflesso]] [[he:רפלקס]] [[lv:Reflekss]] [[lt:Refleksas]] [[nl:Reflex (biologie)]] [[ja:反射 (生物学)]] [[no:Refleks]] [[pl:Odruch]] [[pt:Reflexo]] [[ro:Reflex]] [[ru:Рефлекс (биология)]] [[sk:Reflex]] [[fi:Refleksi]] [[sv:Reflex (medicinsk term)]] [[tr:Refleks]] [[zh:反射 (生理学)]]