下位運動ニューロン
WordNet
- unrefined in character; "low comedy"
- an air mass of lower pressure; often brings precipitation; "a low moved in over night bringing sleet and snow" (同)depression
- a low level or position or degree; "the stock market fell to a new low"
- used of sounds and voices; low in pitch or frequency (同)low-pitched
- very low in volume; "a low murmur"; "the low-toned murmur of the surf" (同)low-toned
- in a low position; near the ground; "the branches hung low"
- less than normal in degree or intensity or amount; "low prices"; "the reservoir is low"
- literal meanings; being at or having a relatively small elevation or upward extension; "low ceilings"; "low clouds"; "low hills"; "the sun is low"; "low furniture"; "a low bow"
- move something or somebody to a lower position; "take down the vase from the shelf" (同)take_down, let down, get_down, bring_down
- cause to drop or sink; "The lack of rain had depressed the water level in the reservoir" (同)depress
- set lower; "lower a rating"; "lower expectations" (同)lour
- machine that converts other forms of energy into mechanical energy and so imparts motion
- a nonspecific agent that imparts motion; "happiness is the aim of all men and the motor of all action"
- the act of causing something to move to a lower level (同)letting down
- the act of causing to become less
- the act of driving an automobile
PrepTutorEJDIC
- (高さ・位置が)『低い』,低い所にある / (価格・数量・程度などが)『低い』,少ない / (身分・地位などが)『低い』,卑しい / (人格・行為などが)『卑しい』,下劣な,下品な / 《補語にのみ用いて》(体が)『弱った』;元気のない,憂うつな / (供給が)不十分な;(…が)乏しい《+『in』(『on』)+『名』》 / (音・声が)低い,小さい / (生物が)下等な / 『低く』,低い所に / (価格・程度などが)『安く』,低く / 低い声(調子)で;静かに / 最低点,最低水準
- (牛の)モーという鳴き声 / (牛が)モーと鳴く
- (lowの比較級)『もっと低い』,(価格が)もっと安い / 《名詞の前にのみ用いて》『下級の』;低い(下の)ほうの / …‘を'『下げる』,降ろす / 〈価格・程度・量・調子など〉‘を'『下げる』,小さくする,低下させる / 〈人〉‘を'品位(品格)を落とす / 低くなる,下がる,滅る
- (…に向かって)顔をしかめる,まゆをひそめる《+『at(on, upon)』+『名』》 / 〈空模様が〉険悪になる,〈雨などが〉降りそうな / しかめっつら / 険悪な空模様
- (電気の)『モーター』,電動機 / エンジン,(特に)内燃機関 / 《英》自動車(motorcar) / 《名詞の前にのみ用いて》 / モーターの;エンジンの;自動車の / モーター(エンジン)による,自動車による / (神経・筋肉について)運動の / 自動車で行く / …‘を'自動車で運ぶ
- 低くする,低下させる;堕落させる
- (空模様が)険悪な,荒れ模様の / しかめっつらの,(顔つきが)不機嫌な
- 自動車運転〈技術〉,ドライブ
Wikipedia preview
出典(authority):フリー百科事典『ウィキペディア(Wikipedia)』「2014/04/02 01:18:38」(JST)
[Wiki en表示]
Lower motor neurons (LMNs) are motor neurons located in either the ventral horn of the spinal cord and anterior nerve roots (spinal lower motor neurons) or the cranial nerve nuclei of the brainstem and cranial nerves with motor function (cranial nerve lower motor neurons).[1] All voluntary movement relies on spinal lower motor neurons, which innervate skeletal muscle fibers and act as a link between upper motor neurons and muscles.[2][3] Cranial nerve lower motor neurons control movements of the eyes and tongue, and contribute to chewing, swallowing and vocalization.[4]
Contents
- 1 Classification
- 2 Physiology
- 3 Consequences of lesions
- 4 See also
- 5 References
Classification[edit]
Lower motor neurons are classified based on the type of muscle fiber they innervate:
- Alpha motor neurons (α-MNs) innervate extrafusal muscle fibers, the most numerous type of muscle fiber and the one involved in muscle contraction.
- Gamma motor neurons (γ-MNs) innervate intrafusal muscle fibers, which together with sensory afferents compose muscle spindles. These are part of the system for sensing body position (proprioception).
Physiology[edit]
Glutamate released from the upper motor neurons triggers depolarization in the lower motor neurons in the ventral horn, which in turn causes an action potential to propagate the length of the axon to the neuromuscular junction where acetylcholine is released to carry the signal across the synaptic cleft to the postsynaptic receptors of the muscle cell membrane, signaling the muscle to contract.
Consequences of lesions[edit]
Damage to lower motor neurons, lower motor neuron lesions (LMNL) cause muscle atrophy, decreased strength and decreased reflexes in affected areas. These findings are in contrast to findings in upper motor neuron lesions. LMNL is indicated by abnormal EMG potentials, fasciculations, paralysis, weakening of muscles, and neurogenic atrophy of skeletal muscle. Bell's Palsy, Bulbar palsy, Poliomyelitis and Amyotrophic lateral sclerosis (ALS) are all pathologies associated with lower motor neuron dysfunction.[5][6]
See also[edit]
- Upper motor neuron
- Upper motor neuron lesion
- Lower motor neuron lesion
References[edit]
- ^ Fletcher, T.F. "Clinical Neuroanatomy Guide". Retrieved 8 November 2013.
- ^ Burke, Robert (2007). "Sir Charles Sherrington's The integrative action of the nervous system: a centenary appreciation". Brain: A Journal of Neurology 130 (4): 887–894. doi:10.1093/brain/awm022. PMID 17438014. Retrieved 8 November 2013.
- ^ Bear, Connors, Paradiso (2007). Neuroscience: Exploring the Brain. Lippincott Williams & Wilkins. pp. 426–432. ISBN 978-0-7817-6003-4.
- ^ Saim, Muhammad. "Upper and Lower Motor Neurons". Retrieved 8 November 2013.
- ^ Sanders, RD (Jan 2010). "The Trigeminal (V) and Facial (VII) Cranial Nerves: Head and Face Sensation and Movement.". Psychiatry (Edgmont) 7 (1): 13–6. PMID 20386632. Retrieved 8 November 2013.
- ^ Van den Berg, et. al (Nov 2003). "The spectrum of lower motor neuron syndromes". J. Neurol. 250 (11): 1279–92. doi:10.1007/s00415-003-0235-9. PMID 14648143. Retrieved 8 November 2013.
Histology: nervous tissue (TA A14, GA 9.849, TH H2.00.06, H3.11)
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CNS |
General |
- Grey matter
- White matter
- Projection fibers
- Association fiber
- Commissural fiber
- Lemniscus
- Funiculus
- Fasciculus
- Decussation
- Commissure
- meninges
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Neuroglia |
insulating: |
- Myelination: Oligodendrocyte
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other |
- Astrocyte
- Ependymal cells
- Microglia
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Other |
- Pyramidal
- Purkinje
- Granule
- Neuropil
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PNS |
General |
- Posterior
- Anterior
- Ramus communicans
- Autonomic ganglion (Preganglionic nerve fibers
- Postganglionic nerve fibers)
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Connective tissues |
- epineurium
- perineurium
- endoneurium
- nerve fascicle
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Neuroglia |
- Myelination: Schwann cell
- Neurolemma
- Myelin incisure
- Myelin sheath gap
- Internodal segment
- Satellite glial cell
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Neurons/
nerve fibers |
Parts |
Perikaryon |
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Axon |
- Axon terminals
- Axoplasm
- Axolemma
- Neurofibril/neurofilament
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Dendrite |
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- Nissl body
- Dendritic spine
- Apical dendrite/Basal dendrite
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Types |
- Bipolar
- Unipolar
- Pseudounipolar
- Multipolar
- Interneuron
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Afferent nerve fiber/
Sensory nerve |
- GSA
- GVA
- SSA
- SVA
- fibers
- Ia
- Ib or Golgi
- II or Aβ
- III or Aδ or fast pain
- IV or C or slow pain
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Efferent nerve fiber/
Motor nerve |
- GSE
- GVE
- SVE
- Upper motor neuron
- Lower motor neuron
- α motorneuron
- β motorneuron
- γ motorneuron
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Termination |
Synapse |
- Electrical synapse/Gap junction
- Chemical synapse
- Synaptic vesicle
- Active zone
- Postsynaptic density
- Ribbon synapse
- Neuromuscular junction
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Sensory receptors |
- Meissner's corpuscle
- Merkel nerve ending
- Pacinian corpuscle
- Ruffini ending
- Muscle spindle
- Free nerve ending
- Olfactory receptor neuron
- Photoreceptor cell
- Hair cell
- Taste bud
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anat (n/s/m/p/4/e/b/d/c/a/f/l/g)/phys/devp
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noco (m/d/e/h/v/s)/cong/tumr, sysi/epon, injr
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proc, drug (N1A/2AB/C/3/4/7A/B/C/D)
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anat (h/r/t/c/b/l/s/a)/phys (r)/devp/prot/nttr/nttm/ntrp
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noco/auto/cong/tumr, sysi/epon, injr
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Motor system
UpToDate Contents
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English Journal
- Recent advances in bulbar syndromes: genetic causes and disease mechanisms.
- Manole A1, Fratta P, Houlden H.
- Current opinion in neurology.Curr Opin Neurol.2014 Oct;27(5):506-14. doi: 10.1097/WCO.0000000000000133.
- PURPOSE OF REVIEW: With advances in next-generation gene sequencing, progress in deep phenotyping and a greater understanding of the pathogenesis of motor neuron disease, our knowledge of the progressive bulbar syndromes has significantly increased in recent years. This group of heterogeneous condit
- PMID 25159929
- Changes in motor unit properties in SOD1 (G93A) rats.
- Kryściak K1, Grieb P, Celichowski J.
- Muscle & nerve.Muscle Nerve.2014 Oct;50(4):577-586. doi: 10.1002/mus.24196. Epub 2014 Aug 5.
- Introduction: In amyotrophic lateral sclerosis (ALS), progressive death of motor neurons results in denervation and reinnervation of muscles. It is not clear how ALS affects the properties of motor units (MUs). Methods: Properties of single MUs in the medial gastrocnemius (MG) muscle of rats bearing
- PMID 24488615
- Slowly progressing lower motor neuron disease caused by a novel duplication mutation in exon 1 of the SOD1 gene.
- Nakamura A1, Kuru S2, Hineno A3, Kobayashi C3, Kinoshita T3, Miyazaki D3, Ikeda S3.
- Neurobiology of aging.Neurobiol Aging.2014 Oct;35(10):2420.e7-2420.e12. doi: 10.1016/j.neurobiolaging.2014.04.012. Epub 2014 Apr 19.
- Familial amyotrophic lateral sclerosis accounts for about 5% of all cases of the neurodegenerative disorder amyotrophic lateral sclerosis. Genetic mutations in Cu/Zn superoxide dismutase (SOD1) have been associated with one kind of familial amyotrophic lateral sclerosis (ALS1). We identified a novel
- PMID 24838187
Japanese Journal
- 杉内 友理子,高橋 真有
- Equilibrium research 70(2), 89-94, 2011-04-01
- … Our recent study showed the presence of commissural inhibition between the upper and lower fields of motor map of the bilateral SCs. …
- NAID 10029512309
- Familial ALS with G298S Mutation in TARDBP: A Comparison of CSF Tau Protein Levels with those in Sporadic ALS
- Nozaki Ichiro,Arai Makoto,Takahashi Kazuya,Hamaguchi Tsuyoshi,Yoshikawa Hiroaki,Muroishi Toyoteru,Noguchi-Shinohara Moeko,Ito Hiroki,Itokawa Masanari,Akiyama Haruhiko,Kawata Akihiro,Yamada Masahito
- Internal Medicine 49(12), 1209-1212, 2010
- … We report a 52-year-old Japanese man showing both upper and lower motor neuron signs with familial amyotrophic lateral sclerosis (ALS). …
- NAID 130000251656
Related Links
- Lower motor neurons (LMNs) are the motor neurons connecting the brainstem and spinal cord to muscle fibers, bringing the nerve impulses from the upper motor neurons out to the muscles. A lower motor neuron's axon terminates on an ...
Related Pictures
★リンクテーブル★
[★]
- 英
- α motoneuron, α-motoneuron
- 同
- 下位運動ニューロン lower motor neuron LMN
- 関
- 運動ニューロン、上位運動ニューロン、γ運動ニューロン
臨床関連
[★]
- 同
- 下位運動ニューロン lower motor neuron
- 関
- 運動ニューロン
[★]
- 英
- lower motor neuron, LMN
- 関
- α運動ニューロン
[★]
- 関
- lower motor neuron
[★]
下位運動ニューロン
[★]
- (low比較級)より低い、下位の、下等な、低次の、低下させる、低減させる
- 関
- decline、decrease、depression、drop、fall、inferio、inferior、inferiorly、low level、lower dimension、lower level、lower order、lowering、reduction
[★]
- 関
- deficient、inadequate、insufficiency、insufficient、insufficiently、poorly、scanty
[★]
- 関
- exercise、kinesis、locomote、locomotive、motility、motion、move、movement
[★]
- 関
- decline、decrease、depression、drop、fall、lower、reduction
[★]
- 関
- nerve、nervi、nervous、nervus、neural、neuron