nervous system

TheNervousSystemandBrain

ABriefOverview概述oftheHumanNervousSystem

Everyhumanbeingusabrainbutironicallymanypeoplecannotsuccessfullynameevery

partofthiscrucial关键的heyunderstandhowthebraincommunicateswith与

交往therest剩余的lofthisknol

aunitofknowledge(知识单元)

istogiveaveryrough

粗略的summary概要ofthevariouspartsofthebrainandnervoussystem.

Contents

Introduction

NervousSystem

NeuronFunction

BrainStem

TheCerebellum

TheDiencephalon间脑

LimbicSystem边缘系统

TheBasalGanglia

Amygdala扁桃体[əˈmiɡdələ]

Hippocampus海马[,hipə'kæmpəs]

Introduction

TheAncientEgyptiansbelievedthatthehumanheartwaswhatheldone'ssoul,

thoughts,,thebrainwasnothingbutagiantglobofmucus黏液

thatpasdsnot鼻涕downtotheno.[1]Forhundredsoreventhousandsofyears,the

Egyptiansandvariousotherculturesaroundtheglobedidnotrecognizethebrain's

overtime随着时间的推移,however,peoplebegantorealizejusthow

rwardto快进the20thand21stcentury,and

therehasbeenalotofinformationunearthed发掘aboutthebrainthroughvarious

ettingclorandclortounderstandingeachandeverypartofthe

centralnervoussystem,owabletocontrolexternal

devicesusingnothingbuttechnologythatdeciphers破译辨认theirbrainwaves.[2]

Scientistsarealsotryingtobuildanartificialbrainthatfillsinthelinkbetween

technologyandbiology.[3]Thehumanbrainisarguably可论证的themostcomplicated

thingintheentireuniver全宇宙.Withitweareabletoufivenstoexperience经历体验

theworldaroundus,rememberourpast,othis

thereisstillalotwedon'tknow,thelevelat

whichwenowcomprehendourbrainandnervoussystemisimpressive给人印象深刻的tosay

theleast.

NervousSystem

ationis

同样的,thebrainisabletond

lowsustorun,write,e,talk,etc.

Thenervoussystemisanintricate复杂的systemcomprid包含mostlyofnervecells(or

neurons).Nervecellsareabletoprocess,relay转达,andstoreinformationandthereare

over50variations变化ofneuronsandeachisspecificallysuited适合totherequirements

voussystemcanbedividedintotwoparts,

thecentralnervoussystemandtheperipheralnervoussystem.

CentralNervousSystem(CNS)

Therearethreemaincomponents成分thatmakeupthecentralnervoussystem;the

brain,spinalcord,andnervoustract束.[5]Thecentralnervoussystemincad装箱in

thebackbone脊骨andasystemofmembranes细胞膜calledthemeninges脑膜whichboth

ingesiscompodofthreelayers:theduramater硬脑膜,

arachnoid蛛网膜,andpiamater软脑膜.

Thebloodbrainbarrier(BBB)血脑屏障he

protectivefactorsarevitalforoursurvival生存becauiftheyaredamagedthenitcan

leadtoriousinjuryordeath.

PeripheralNervousSystem(PNS)

Theperipheralnervoussystemiscompridofthebranchesofnervesthatextend

fromthecentralnervoussystemtotherestofourbody.[6]Thenervefibersarenot

protectedlikethecentralnervoussystemwhichmeanstheyaremorevulnerable敏感的，易

受伤的reanumberofdifferentkindsofnervecellsthatarepartof

thePNS

AfferentNeurons-Nervesintheperipheralnervoussystemthatcarry

informationtowardthecentralnervoussystemarecalledafferentneurons(or

nerves).[4]Afferentneuronscommunicatewithinterneurons中间神经元that

gs,suchaspaininthe

legsorarms,arentalongafferentneuronstothebrainwherethepaincanbe

registered.

EfferentNeurons-Alsoknownasmotorneurons,efferentneurons(ornerves)

carryinformationfromthebrainandspine脊椎ourintotheotherareasofthe

body.[7]Efferentneurons,forexample,keepourheartsbeating,ourlungs

breathing,andalsoallowustomoveourbodies.

euronsconnect

nervestoothernervesandthereforedonotconnecttoanymusclesorothernsory

reabout100

billioninterneuronsinthehumanbody.[8]

GlialCells神经胶质细胞-Keepingallofthenervesprotectedandinplacearetheglialcells.

Therearearoundtentimesasmanyglialcellsasthereareotherneuronsinthe

brain.[9]Theysurroundneuronsand'glue'so

provideneuronswithoxygenandnutrientsaswellasdestroypathogens病原体andhelp

controlneurotransmission.神经传递

NeuronFunction

Thenervoussystemixtremelycomplexandhasaround100billionneuronsthat

sworkthroughaprocesscalledaction

potential动作电位,whichinvolveschemicalreactionsthatdeterminewhetherornot

potentialsoccurwhencells

areexcitedbeyondtheirthreshold阈值velychargedsodiumionsmove

throughthemembrane细胞膜andintothecell,whichcreatesadisturbance紊乱inthecell

andleadstothedischargeofelectricimpul.

Neuronsreacttoneurotransmitters神经传递素invariousways,dependingonthe

shavereceptor受体感受器

famousneurotransmittersarerotonin血清素,dopamine多巴胺,GABA氨基丁酸,

norepinephrine去甲肾上腺素,andacetylcholine乙酰胆碱.Allofthecanbefoundinvarious

partsofthebody,salsohavedendrites树突,

axons轴突,andsynaps突触.

Dendrites-Thearebranchprojectionsstemmingoutofaneuronthatbring

tesareveryimportantincarryingoutaction

potentialsandintegrating结合synaps.[10]Theyreachout伸出tosurroundingneurons

endritehas

detectedanelectricalsignalitwillnditdownintothecellbodyitisbranchedout

anbemanydendritebranchesononeneuron.

Axons-Alsoknownasnervefibers,theareprojectionswhichtakeinformation

awayfromthecell.[11]Muchlikedendrites,theybranchawayfromthecellbody

andhaveelectricalimpulscoursingthroughthem,onlythistimetheyareheading

anbeonlyoneaxononeachneuron.

MyelinSheaths髓鞘-Axonsareinsulated绝缘的withamyelinsheaththat

ultimately最后sheathsreducethechance

illimeteror

sothesheathisbrokenupwithproteinpacked大量gapscalledNodesof

Ranvier郎飞结.Atthegaps,theelectricalsignalisabletorechargethrough

saltatoryconduction跳跃式传导epsthe

signalstrongandcapableoftravellinglongdistancesinthebody.

Synaps-Thesynapisthepointonaneuronwhereinformation,intheformof

ions,esareverytinygapsthatallowsignalstodiffu扩散from

acrucialpartofthenervoussystemandbrainbecauit

apcontainsthreedifferent

parts:apresynapticending突触前末梢,postsynapticending突触后末梢,andsynapticcleft.[12]

Presynaptic-Thiscontainsmitochondria线粒体,neurotransmitters,andother

cellorganelles细胞器.

Postsynaptic–Receptor感受器、受体siteforneurotransmitters.

SynapticCleft突触间隙-Aspacebetweenthepresynapticandpostsynaptic

whereneurotransmittersarediffudandtransferredovertotheneighboring

dendrites.

Therearethreedifferentkindsofsynaps:Axodendritic轴-树的,Axosomatic轴-体的,

Axoaxonic轴-轴的.Synapticterminalshavevesicles囊toamplify扩大、增强ormodulate调节

micalsignalsthatthe

terminalsreceivewilldeterminewhetherornotthecellwilldecreathestrengthof

ctricalimpulsreceivedinthecellarecalledactionpotentials.

Actionpotentialscontinuallyrepeatasthebrainanditsneuronsdotheirjob.

BrainStem

Atthetopofthespinalcord,beforethebrain,thereisajunctionthatconnectsthe

twoandiscalledthebrainstem(reptilian爬行动物的brain).Thebrainstemgoesfromthe

abouttenpercentofthe

entirenervoussystem.[13]Therearethreepartsthatmakeupthebrainstem.

MedullaOblongata延髓-Thisisthelowerpartofthebrainstemandismostly

incontrolofinvoluntary无意识的,autonomicfunctionslikebreathing,heartrate,

bloodpressure,relays传达nervesignalsbetweenthebrain

andspinalcord.

Pons桥脑-shelpsthe

medullaoblongatawithsomeofitsfunctions,butmostlyitrelaysnsory

informationthathelpsuswithourmovement,arousal觉醒,andrespiration呼吸.

Theponshelpsthecerebellumandcortexcommunicatewitheachother.

Midbrain中脑-Themidbrainisacurvingstructureatthetopofthebrainstem

andhelpstocontrolandcoordinate协调thebody'snsoryandmotorfunctions.

Themidbrainmightalsoinfluenceaggressivebehavior.

TheCerebellum

thecerebellumisaboutonetenthoftheentirebrain'svolumeithousalmosthalfthe

amountofneuronsinthebrain!Thesurfaceofthecerebellumhasmanymorelines

runningacrossitandisthereforemorecompact紧密

cerebellumhastwohemispheresandwasoneofthefirstpartsofthebraintoever

evolve.[15]Itisoneofthemostimportantpartsofthebrainforitsabilitytointegrate

nsoryperception,motorcontrol,idesusbalanceand

movement,aswellasdeciphering辨认

scientistsalsobelievethatthecerebellumhelpsusprocesslanguageandmusicand

givesusourabilitytopayattention,amongotherthings.[14]Thecerebellumnds

informationintothebrainstemwhichisthendeliveredtotherestofthebrain.

TheDiencephalon

Betweenthecerebralhemispheresandabovethemidbrainthereisaregionofthe

ainstwoveryimportantsubstructures.

Thalamus-Adual-lobedstructuremadeofgreymatter,thethalamusreceives

anddeciphersnsoryinformation.[16]Onceithasprocesdnsory

informationthethalamuschooswhetherornotthatinformationshouldbe

lamusreceivesinformationfrompartsofthe

brainandbodythathavetodowithmovementandnsoryinformation.

Signalsfromthecerebellumandcerebralcortexarenttothethalamusand

thethalamusndssignalsoutintothecortex.

Hypothalamus-Thehypothalamusisinchargeofmakingsurethatwestay

beneaththethalamusandisconnectedtomosteverythingin

othalamuscausustoekpleasurableactivitieslike

havingx,eatinganddrinking,listeningtomusic,lates

hormones激素thatinfluencehowmuchweeatordrinkandhowwe

behave.[17]Thehypothalamusalsomanagesthecircadianrhythm昼夜节奏,our

bodytemperature,andinstinctual本能reactionssuchasthefightorflight

tainshomeostasis.体内平衡

LimbicSystem

Thelimbicsystemiscompridofagroupofbrainstructuresthatareimportantin

re

threekeyareasinthelimbicsystem.

TheBasalGanglia基底神经节

mpridofa

gro

basalgangliareceivesmostofitsinformationfromthecortexandiscriticaltoour

abilitytomove.[18]Whenthebasalgangliaisdamageditverelyimpairs

someone'sabilitytocontroltheirbody,ascanbeeninthowithHutchinson's

DiaorParkinson'sDia.

Amygdala

Asmallbutpowerfulareaofthebrain,theamygdalaisbelowthehypothalamus丘

脑下部andhelpsusprocesstheworldatlarge详细的.Theamygdalaisresponsiblefor为…负责

regulatingemotions,affectingourrelationships关系andwell-being健康.Italsoplaysa

partincausingarousal觉醒.Automaticreactionslikefearareinlargepartcaudbythe

amygdala.[19]

Hippocampus

Nexttotheamygdalaandpartoftheforebrainisthehippocampus,whichis

shapedsomewhat有点pocampusiskeyincreatingnew

memoriesbyforgingnewneuralpathwaysinourminds.[20]Thehippocampusalso

helpsuswithspatialorientationandsleeppatterns.

TheCerebralCortex大脑皮层

Thecerebralcortexisthelargest,eouter

ebralcortexis

folded褶皱sothatallthespacecanfitinsideofasingleskull颅骨.Thefoldsarewhat

givethebrainitswrinkled皱纹faceofthecortexisgreymatterand

hthelayersiswhite

matterandwhenalloftheareputtogetherwearegivenahugenumberof

connectionsthatfacilitateourabilitytothink,feel,andreason.

Thecerebralcortexhastwohemispheresandeachhemispherehelpstomanage

ehemispherescancommunicate

withoneanother,andcanbedividedintofourdifferentlobes.

FrontalLobe额叶-

giveshumanstheirhigherlevelthinkingskills,suchastheabilitytoplan,pay

attention,ulanguage,andmove.[21]Itisabletocontrolmuchoftheother

s

ustheabilitytodecidehowwewanttoactbadontheinformationwe

receivefromtherestofourmindandbody.

ParietalLobe顶叶-Theparietallobeisbehindthefrontallobesandatthetop

istointegrate融合nsoryinputandgiveusperception感知.

Italsogivesusabilitytodomath,ulanguage,tis

linkedtovisual视觉systems,theparietallobeshelpustodothingslikebutton

ourshirtsorthrowfootballs.[22]

OccipitalLobe枕叶-Theoccipitallobesmakeupthemainvisualprocessing

attheverybackofourbrain,slightlybelowthe

parietallobe.[23]susabilityto

spatiallyorientate空间定向力tthe

occipitallobewewouldnotbeabletodoanythingwhichrequiressight.

TemporalLobe颞叶-Thetemporallobespansacrossthebrainandisbelow

susourabilitytohearby

processingauditoryinformation.[24]Thisauditoryprocessingcenterhelpsus

porallobecontainsthehippocampuswhich

makesitimportantintheformationandretrieval恢复ofmemories.

CorpusCallosum胼胝体

Thecorpuscallosumconnectsthebrain'uge

bundleofnervefibersthatallowsinformationtopassbetweenthetwopartsofthe

brain.[25]Thecorpuscallosumallowsforoptimal最佳的performancefromthebrain.

Someepilepsy癫痫patientswillhavetheircorpuscallosumcut,leavingthetwo

hemispheresoftheirbrainparatedfrom分开eoplearestillableto

functionbutarenotabletoprocessthingsthesamewayapersonwithanintact完整无缺的

reexperimentsandstudiesdoneon"split-brain"patients,

astheyarecalled,totryandfigureout想出、计算出howthecorpuscallosumaffects

consciousness意识andcognitiveabilites认知能力.

Conclusion

Thenervoussystemandbrainareverycomplicatedandcannotbecompletely

summedup总结r,thisarticlehasoutlined概述allofthemajor

pointsregarding关于mindthattherearealwaysstudiesgoing

ontotryandunravel解开alot

terwe

understandthepartsofourbodies,thebetterwecanunderstandhumansandtheir

societiesasawhole.

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