WordNet
- an automatic instinctive unlearned reaction to a stimulus (同)reflex response, reflex action, instinctive reflex, innate reflex, inborn reflex, unconditioned_reflex, physiological reaction
- a continuous portion of a circle
- forming or resembling an arch; "an arched ceiling" (同)arched, arching, arciform, arcuate, bowed
- (of leaves) bent downward and outward more than 90 degrees
PrepTutorEJDIC
- 反射(刺激に対する無意識の反応) / 《複数形で》反射的な動き / (光などの)反射,反射光;映像 / 反射性の / (カメラが)レフ鋼の,反射型の
- 『弧』,円弧 / 電弧(2点間を弧状に流れる電流) / 弧を描く / 電弧を生じる
- American Red Crossアメリカ赤十字
Wikipedia preview
出典(authority):フリー百科事典『ウィキペディア(Wikipedia)』「2013/10/21 15:41:32」(JST)
[Wiki en表示]
A reflex arc is a neural pathway that controls an action reflex. In higher animals, most sensory neurons do not pass directly into the brain, but synapse in the spinal cord. This characteristic allows reflex actions to occur relatively quickly by activating spinal motor neurons without the delay of routing signals through the brain, although the brain will receive sensory input while the reflex action occurs.
There are two types of reflex arc: autonomic reflex arc (affecting inner organs) and somatic reflex arc (affecting muscles).
Contents
- 1 Monosynaptic vs. polysynaptic
- 2 The patellar reflex (knee jerk)
- 3 References
- 4 External links
Monosynaptic vs. polysynaptic[edit]
When a reflex arc consists of only two neurons in an animal (one sensory neuron, and one motor neuron), it is defined as monosynaptic. Monosynaptic refers to the presence of a single chemical synapse. In the case of peripheral muscle reflexes (patellar reflex, achilles reflex), brief stimulation to the muscle spindle results in contraction of the agonist or effector muscle. By contrast, in polysynaptic reflex pathways, one or more interneurons connect afferent (sensory) and efferent (motor) signals. All but the most simple reflexes are polysynaptic, allowing processing or inhibition of polysynaptic reflexes within the brain.
The patellar reflex (knee jerk)[edit]
Main article: Patellar reflex
When the patellar tendon is tapped just below the knee, the patellar reflex is initiated and the lower leg kicks forward (via contraction of the quadriceps). The tap initiates an action potential in a specialised structure known as a muscle spindle located within the quadriceps. This action potential travels to the spinal cord, via a sensory axon which chemically communicates by releasing glutamate (see synapse) onto a motor nerve. The result of this motor nerve activity is contraction of the quadriceps muscle, leading to extension of the lower leg at the knee. The sensory input from the quadriceps also activates local interneurons that release the inhibitory neurotransmitter glycine onto motor neurons, blocking the innervation of the antagonistic (hamstring) muscle. The relaxation of the opposing muscle facilitates extension of the lower leg.
In lower animals reflex interneurons do not necessarily reside in the spinal cord, for example as in the lateral giant neuron of crayfish.
References[edit]
- Ganong, W. F. (2001). Review of Medical Physiology. McGraw-Hill Publishing, New York, p. 123.
External links[edit]
- Ole K. Andersen, SMI, Aalborg University - Physiological and Pharmacological modulation of the human nociceptive withdrawal reflex at smi.auc.dk
- Somatic Reflex Arc at vetmed.vt.edu
- Reflex+arc at eMedicine Dictionary
- "Reflex arc" at Dorland's Medical Dictionary
- Overview at sfsu.edu
- Overview at rutgers.edu (with animation)
- 06-077c. at Merck Manual of Diagnosis and Therapy Home Edition - "Physical Examination"
- Tutorial at wisc-online.com
UpToDate Contents
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English Journal
- Involvement of histaminergic inputs in the jaw-closing reflex arc.
- Gemba C1, Nakayama K2, Nakamura S2, Mochizuki A2, Inoue M3, Inoue T2.
- Journal of neurophysiology.J Neurophysiol.2015 Jun;113(10):3720-35. doi: 10.1152/jn.00515.2014. Epub 2015 Apr 22.
- Histamine receptors are densely expressed in the mesencephalic trigeminal nucleus (MesV) and trigeminal motor nucleus. However, little is known about the functional roles of neuronal histamine in controlling oral-motor activity. Thus, using the whole-cell recording technique in brainstem slice prepa
- PMID 25904711
- Open-loop characteristics of the arterial baroreflex after blockade of unmyelinated baroreceptors with resiniferatoxin.
- Turner MJ1, Kawada T2, Shimizu S2, Fukumitsu M3, Sugimachi M3.
- Autonomic neuroscience : basic & clinical.Auton Neurosci.2015 May 30. pii: S1566-0702(15)30001-1. doi: 10.1016/j.autneu.2015.05.008. [Epub ahead of print]
- Arterial baroreceptors can be divided into two categories dependent on whether their axons are myelinated (A-fiber) or unmyelinated (C-fiber). We investigated the effect of periaxonal resiniferatoxin (RTX), a blocker of C-fiber baroreceptor activity, on the open-loop static characteristics of the ar
- PMID 26049262
- Hiccups and amniotic fluid regulation in early pregnancy.
- Murchison AG1.
- Medical hypotheses.Med Hypotheses.2015 May;84(5):448-50. doi: 10.1016/j.mehy.2015.01.040. Epub 2015 Jan 31.
- Hiccups are an unexplained phenomenon and a subject of medical curiosity. They arise through a reflex arc with central control at the level of the medulla, and their primary physiological effect is the generation of negative intra-thoracic pressure. This paper presents the hypothesis that hiccups se
- PMID 25754848
Japanese Journal
- Spinal Reflex Arc Excitability Corresponding to the Vastus Medialis Obliquus and Vastus Medialis Longus Muscles
- Tanino Yoshitsugu,Suzuki Toshiaki
- Journal of Physical Therapy Science 26(1), 101-104, 2014
- … To elucidate spinal reflex arc excitability in two divisions of the VM, we compared H-reflexes and T-waves in VMO and VML. … [Methods] The H-reflex was evoked from the VMO and VML by electrical stimulation of the femoral nerve during knee extension at 10% maximal voluntary isometric contraction. … [Results] The configurations of the H-reflex and T-wave were sharp and slow in VMO and VML, respectively. …
- NAID 130004432120
- 頸部術後に CRPS (Complex Regional Pain Syndrome) tupe I を生じた1例
- 矢吹 健一郎,佃 守,谷垣 裕二 [他],池田 陽一,愛甲 健,小山 主夫
- 耳鼻咽喉科臨床 103(1), 65-69, 2010-01-01
- … CRPS might be caused by the formation of an abnormal reflex arc between the sympathetic nervous system and peripheral vascular components after a causative event. …
- NAID 10026216431
- 大瀧 亮二,佐藤 寿晃,長沼 誠,鈴木 克彦,成田 亜矢,佐藤 麻人,宮坂 卓治,藤井 浩美,内藤 輝
- 形態・機能 8(1), 13-18, 2009
- ヒトでは、橈側手根屈筋(FCR)は前腕の回内、橈側手根伸筋(ECR)は回外に作用する。本研究では、健常者8名を対象に、手根の屈曲と伸展が前腕の回外力に及ぼす効果について調べた。前腕回内90°(回内)、60°、30°、0°(中間)位で、手根の力を抜いた状態、最大屈曲および伸展した状態で等尺性収縮による回外(それぞれ回外単独、屈曲回外、伸展回外とする)の最大力を計測し、FCR、ECR、上腕二頭筋(BB …
- NAID 130005064040
Related Links
- reflex arcとは。意味や和訳。反射弓 - 80万項目以上収録、例文・コロケーションが豊富な無料英和和英辞典。 ... で始まる で一致する で終わる を説明文に含む を見出しに含む
- In its simplest form, a reflex is viewed as a function of an idealized mechanism called the reflex arc. The primary components of the reflex arc are the sensory-nerve cells (or receptors) that receive stimulation, in turn connecting to ...
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