Chapter2

ExcitationandConductioofnervous

神經(jīng)的興奮與傳導(dǎo)

Metabolism新陳代謝Reproduction生殖Excitability興奮性Nervoustissue

：nervecells

(neuron,神經(jīng)元)

functionalcells(功能細(xì)胞)

neurogliacells(神經(jīng)膠質(zhì)細(xì)胞).Support,nutrition,protectionandisolation(絕緣).NF(nervefiber):longtubercleofneuron

axonandlongdendrite.N(neuron):NF+connectivetissue(結(jié)締組織)Fig2-2Section1IrritabilityandExcitability

應(yīng)激性與興奮性1.Irritability應(yīng)激性

Def:Itisakindofcapacitythatthevivotissue andcellsgeneratereactionforstimulus.

活的機(jī)體、組織、細(xì)胞對(duì)刺激發(fā)生反應(yīng)的能力

Example:amoeba(變形蟲(chóng)),sensitiveplant(含羞草), tendentialofplant(植物的向性)andsilk tree(合歡).

condition:(1)sensibilityforstimulus(2)signalconductibility(3)reactionofeffecterExcitablecell:sensitivecell,nervecell,musclecellExcitability:irritabilityofexcitablecells2.Excitability興奮性excitation興奮：

Reactionofvivotissueandcellforstimulus活組織或細(xì)胞對(duì)刺激發(fā)生的反應(yīng)

transform變遷

Stimulatedcellsgenerateactionpotential細(xì)胞受刺激時(shí)產(chǎn)生動(dòng)作電位

Excitability：

akindofcapacitythatvivotissueandcellgeneratereactionforstimulus.活組織或細(xì)胞對(duì)刺激發(fā)生反應(yīng)的能力

transform(變遷)akindofcapacitythatcellgenerateAPforstimulus細(xì)胞受刺激時(shí)產(chǎn)生動(dòng)作電位的能力

transform(變遷)akindofpeculiaritythatcellularmembraneconductanceischangedforstimulus

細(xì)胞受刺激時(shí)膜電導(dǎo)產(chǎn)生改變的特性

Example:

thesampleofSciaticnerve-gastrocnemiusmuscle

(坐骨N-腓腸肌標(biāo)本)Section2stimulationofcausingexcitation

引起興奮的刺激1.Def:Itisakindofchangeofinternalandexternalenvironmentwhichcancausecellexcitation

能引起細(xì)胞興奮的內(nèi)外環(huán)境條件的變化2.QualityandClassification性質(zhì)與種類Quality:mechanicalstimulus,chemicalstimulus,temperaturestimulus,electricalstimulusect.electricalstimulus:theelectricalstimulusofrectanglarwaves(矩形波電刺激),controllablestrength-duration(強(qiáng)度與時(shí)間可控),littledamage3.Essentialfactorsofstimulus刺激的要素(1).intensity強(qiáng)度:

Thresholdintensity(閾強(qiáng)度)：Whenstimulusdurationandrateofchangeisstable,tissuecangenerateexcitationbyaminimalintensityofstimulus,theminimalintensityofstimulusiscalledthresholdintensity.刺激持續(xù)時(shí)間和強(qiáng)度-時(shí)間變化率固定時(shí),引起組織興奮所需的最小刺激強(qiáng)度。

Thresholdstimulus(閾刺激):Itisakindofstimulusthatintensityisequaltothresholdintensity.

Subthresholdstimulus(閾下刺激)：

Itisakindofstimulusthatintensityislessthanthresholdintensity.Supraliminalstimulus(閾上刺激)：

Itisakindofstimulusthatintensityismorethanthresholdintensity.Maximalintensity(頂強(qiáng)度):Itistheminimalintensityofstimuluswhichcancausemuscletodothemostcontractionreaction.引起肌肉做最大收縮反應(yīng)的最小刺激強(qiáng)度。Allornone(全或無(wú)):Forsinglecell,oncethresholdintensityisreached,thecellwillgeneratethemaximalreaction.對(duì)單個(gè)細(xì)胞來(lái)說(shuō),一旦刺激強(qiáng)度達(dá)到閾值,就會(huì)引起這個(gè)細(xì)胞作最大反應(yīng)。(2)Duration

Thestrength-durationcurveofexcitedtissue

強(qiáng)度-時(shí)間曲線Fig2-6

Rheobase(基強(qiáng)度):theminimalthresholdintensity. 最小的閾強(qiáng)度Effectivetime(效用時(shí)間):(utilizationtime利用時(shí)).Itistheshorteststimulativetimewhichcanexcitetissuebystimulusofrheobase.

用基強(qiáng)度刺激,引起興奮所需要的最短刺激時(shí)間(3).Rateofchange(強(qiáng)度的變化率)Fig2-7Section3IndexandVariationofexcitability

興奮性的指標(biāo)和興奮性的變化1.Indexofexcitability興奮性的指標(biāo)(1).Rheobaseandthresholdintensity

基強(qiáng)度與閾強(qiáng)度

excitability∝1/rheobaseorthresholdintensity

Forexample：

AmuscleBmusclethreshold0.7V1.2Vexcitabilitystrongerweaker2.Chronaxie時(shí)值Def:Whentheintensityofstimulusistwiceasrheobase,theshortestdurationofstimulus,whichcanexcitetissue,iscalledchronaxie.當(dāng)刺激強(qiáng)度為基強(qiáng)度的二倍時(shí),引起興奮所需的最短刺激作用時(shí)間excitability∝1/chronaxie3.changesofexcitabilityduringactionpotentialandresumption

(組織興奮及其恢復(fù)過(guò)程中興奮性的變化)phasesexcitabilityresponseAbsoluterefractoryzeronoresponseperiod絕對(duì)不應(yīng)期Relativerefractorylowerthanresponsefor period相對(duì)不應(yīng)期 normal supraliminalstimulusSuperanormalalittlehigherresponseforperiod超常期thannormal subthresholdstimulusSubnormalalittlelowerresponseforperiod低常期thannormal supraliminalstimulus

1.Discoveryofbioelectricity生物電的發(fā)現(xiàn)電鰻numbfish伽發(fā)利Galvani(1737－1798）動(dòng)物電

animalelectricity伏特volt雙金屬電流

AcurrentbytwokindofmetalsFig2-13Section4Bioelectricityphenomena生物電現(xiàn)象2.Restingpotentialandactionpotential

靜息電位與動(dòng)作電位(1)Injurypotential損傷電位Def:Thepotentialdifferencebetween injurysiteandintactsiteoftissue.組織的損傷部位與完整部位之間的電位差Essence:thepotentialdifferenceoftwo sides ofmembrane.膜兩側(cè)的電位差

(2)Restingpotential靜息電位Def：Thepotentialdifferencebetweentwosides ofrestingcellularmembrane.

靜息狀態(tài)下細(xì)胞膜兩側(cè)所存在的電位差Measure:microelectrode(微電極)Extent:-50----100mvPolarization(極化):Undertherestingcondition,themembranehaspolaritythatinteriorisnegativeandexteriorispositive內(nèi)負(fù)外正(3)Actionpotential動(dòng)作電位Def:arapid,reversibleandconductablechangesofmembranepotentialinstimulatedcellonthebaseofRP.細(xì)胞膜受到刺激后在原有RP基礎(chǔ)上發(fā)生的一次膜兩側(cè)電位的快速而可逆的倒轉(zhuǎn)與復(fù)原ProduceandConduction產(chǎn)生與傳播:

Fig2-16Section5

PrincipleofBioelectricityphenomena

生物電現(xiàn)象的產(chǎn)生原理Membranetheory

:ItwassupposedbyBernsteininGermanin1902ForexplainingRP.

Iontheory:SupposedbyHodgkinandHuxleyin1949ForexplainingAP.PrincipleofBioelectricityphenomena:Itisbioelectricityphenomenathatiscausedbyunbalanceddistributionofchargedionsintwosidesofmembraneandchangeofpermeabilityoftheionsunderdifferentcondition.生物電產(chǎn)生的基本原理：細(xì)胞生物電現(xiàn)象的各種表現(xiàn)，主要是由于某些帶電離子在細(xì)胞膜兩側(cè)不均衡分布，以及膜在不同情況下對(duì)這些離子的通透性發(fā)生改變所造成。Transmembranediffusionofchargedions

帶電離子的跨膜擴(kuò)散

KCL0.1molKCL0.01molEK

=59.5log[k+]o/[k+]iK+--++1.RPandEK

Ionsdistributionintwosidesofmembrane:Intracellular:highconcentrationofK+,manynegativeionsformedbyorganicmolecules;

胞內(nèi)高鉀，具較多的由有機(jī)分子形成的負(fù)離子；

extracellular:highconcentrationofNa+,negativeionsaremainlyCl-

胞外高鈉，負(fù)離子以Cl-為主靜息電位與EKTheprincipleofRP：(1)Unbalanceabledistributionofchargedionsintwosidesofmembrane.(2)HighmembranepermeabilityforK+

(3)RPiscausedbyoutwarddiffusionofK+,RPisequaltoEK.RP(靜息電位)的產(chǎn)生機(jī)制：(1)靜息狀態(tài)下帶電離子在膜兩側(cè)呈不均衡分布；(2)靜息狀態(tài)下膜的通透性主要表現(xiàn)為鉀的通透性；(3)RP的產(chǎn)生主要是由于鉀離子的外向擴(kuò)散造成，RP相當(dāng)于EK2.APandchangesofmembranepermeability 動(dòng)作電位與膜的通透性變化proof：

relationshipbetweenNa+andAPFig2-29

Mechanism1ofAP：

whenmembraneisdepolarizedslowlybystimulating,themembrane’spermeabilityisincreasedforNa+,Na+flowintocell,whenitreachesthresholdintensity,Na+enteringisaccelerated,depolarizationisenhanced,membranepotentialandNaconductancegenerateHodgkincycle.Na+rapidenteringformsrisingphase,whentendtoENa,Na+channelisinactivated.AP機(jī)制1細(xì)胞受刺激時(shí)，膜緩慢去極化(depolarization)，膜對(duì)鈉的通透性增加，鈉內(nèi)流，達(dá)到閾電位時(shí)，鈉內(nèi)流，膜進(jìn)一步去極化，膜電位與鈉電導(dǎo)間形成Hodgkincycle,鈉快速內(nèi)流形成AP的上升支，當(dāng)趨近于ENa時(shí)，鈉通道失活。Descendingphase(下降支)：Na+channelsareclosedandK+channelsareopened.K+flowtooutofcell,membranerepolarizes鈉通道關(guān)閉，鉀通道開(kāi)放，鉀外流引起膜復(fù)極化

Mechanism2ofAP

動(dòng)作電位的產(chǎn)生機(jī)制2圖2-423.Na-Kpump’sactivetransport鈉鉀泵的主動(dòng)轉(zhuǎn)運(yùn)Keepingpolarization：(1)Enteringofpositiveions<extrudingofpositiveions運(yùn)進(jìn)的正離子比運(yùn)出的少；(2)ExtrudingofK+>EnteringofNa+

靜息狀態(tài)下鉀外流大于鈉內(nèi)流；(3)Impermeabilityofmanyintracellularorganicnegativeions胞內(nèi)有大量不能通透的有機(jī)負(fù)離子。4.Classicvoltageclampexperiment

經(jīng)典的電壓鉗實(shí)驗(yàn)Designbasis:(1)membraneconductance=membranepermeability(2)I=V.G

ThecharacteristicofchangescurveofGNaandGK

①voltagedependence,activatedbydepolarization,GNawasactivatedearlier.ItwasbaseofrisingphaseofAP,GKwasactivatedlater,itwasbaseofdescendingphaseofAP.

電壓依從性,由去極化激活,GNa激活早是AP上升支基礎(chǔ);GK激活晚，是AP下降支基礎(chǔ)。

電導(dǎo)及AP②GNahasinactivation

butGKnot.

GNa有失活狀態(tài)

而GK沒(méi)有此特性

5.Patchclampexperimentandsinglechannelcurrent

膜片鉗實(shí)驗(yàn)和單通道離子電流

細(xì)胞是通過(guò)細(xì)胞膜與外界隔離的，在細(xì)胞膜上有很多通道，細(xì)胞就是通過(guò)這些通道與外界進(jìn)行物質(zhì)交換的。這些通道由單個(gè)分子或多個(gè)分子組成，允許一些離子通過(guò)。通道的調(diào)節(jié)影響到細(xì)胞的生命和功能。內(nèi)爾和薩克曼合作，結(jié)果發(fā)現(xiàn)當(dāng)離子通過(guò)細(xì)胞膜上的離子通道的時(shí)候，產(chǎn)生十分微弱的電流。內(nèi)爾和薩克曼在實(shí)驗(yàn)中，證實(shí)了離子通道是存在的，以及它們?nèi)绾伟l(fā)揮功能的。有一些離子通道上有感應(yīng)器，他們甚至發(fā)現(xiàn)了這些感應(yīng)器在通道分子中的定位。patchclamp

experiment

Na+current

Channelcharacteristics

：Fig2-37,2-36

①closeoropenofchannelissudden②whenchannelisopen,theyhavestableconductance.③openingtimeisdifferent.④specialsignalscancontrolthechannel’sopeningandclosingSection6

initiationandpropagationofnerveimpulse

神經(jīng)沖動(dòng)的產(chǎn)生與傳導(dǎo)1.initiationofnerveimpulse(initiationofexcitation)神經(jīng)沖動(dòng)的產(chǎn)生(興奮的引起)(1)thresholdpotentialandAP

thresholdpotential(閾電位):itisthecriticalmembranepotentialvalue,whichcancauseAP.膜內(nèi)負(fù)電位去極化到能引起動(dòng)作電位產(chǎn)生的臨界膜電位數(shù)值

(2)localexcitationanditscharacteristic

局部興奮及其特性Localexcitation

：Whencellisstimulated,itsmembranepotentialisslightlydepolarized.Characteristics:細(xì)胞受刺激時(shí)膜電位的輕微去極化①itisincreasedbyincreasingofsubthresholdstimulusintensity隨閾下刺激增大而增大②electrotonicspread電緊張性擴(kuò)布③summationphenomena（總和現(xiàn)象:時(shí)間性、空間性）differencebetweenlocalreactionandAP

局部反應(yīng)與AP的區(qū)別LocalreactionAPCausedbysubthresholdstimulusCausedbysupraliminal

閾下刺激引起閾（上）刺激引起

AfewofNa+channelLotsofNa+channel

Gradedresponse反應(yīng)等級(jí)性

“Allornone

”Summationeffect總和效應(yīng)

Not

DecayedtransmissionUndecayedtransmission衰減性傳播非衰減性傳播MyelinatedNF(有髓鞘NF):

saltoryconduction

(跳躍傳導(dǎo))

LocalcircuitcurrentofnodeofRanvier(朗飛氏結(jié))ofexcitedandunexcited已興奮的與未興奮的朗飛氏結(jié)間的局部電流Fig2-502.Conductionvelocityofnerveimpulse神經(jīng)沖動(dòng)的傳導(dǎo)速度

Conductionvelocity–NF’sdiameterFig2-22ClassificationofNF:

A.Widest,myelinated(髓鞘)B.wider,myelinatedC.thin,unmyelinated3.Characteristicofnerveimpulseconductance atNF(NF上神經(jīng)沖動(dòng)傳導(dǎo)的特點(diǎn))

(1)isolation(絕緣性)(2)bidirectionalconduction(雙向傳導(dǎo))(3)undecayed(非衰減性)(4)relativeuntired(相對(duì)不疲勞性)(5)physiologicalintact(生理完整性)Synapse(突觸):Thespecializedjunctionbetweentwoneuronswhereanactionpotentialinthepresynapticneuroninfluencesthemembranepotentialofthepostsynapticneuronbymeansofthereleaseofachemicalmessengerthatdiffusesacrossthesmallcleftthatseparatesthetwoneuron.(一個(gè)神經(jīng)元的軸突末梢與其它神經(jīng)元的胞體或突起相接觸的部位)Neuromuscularjunction(神經(jīng)肌肉接點(diǎn)):Belongtoakindofsynapsesingeneral(廣義上屬于一種突觸)1.Thestructureofneuromuscularjunction

(神經(jīng)肌肉接點(diǎn)的結(jié)構(gòu))

Fig3-2Presynapticmembrane(接頭前膜):

Neuronmembrane,ithassynapticvesicleswhichincludechemicaltransmission-acetylcholine(Ach).(神經(jīng)細(xì)胞膜，內(nèi)有突觸小泡，含化學(xué)遞質(zhì)乙酰膽堿)Postsynapticmembrane(接頭后膜):

Alsonamedend-platemembrane,belongstomyocytemembrane,hasreceptorsandacetylcholinesterase.(又叫終板膜，屬肌細(xì)胞膜，有受體，終板柵中有乙酰膽堿酯酶)Junctioninterstice(接頭間隙)：

mucopolysaccharide(粘多糖)2.TransmissionofExcitationInNeuromuscular Junction(興奮在神經(jīng)肌肉接點(diǎn)的傳遞)Transmissionprocess：APreachestotheaxonterminal,calciumchannelopened,andCa2+enterintothefiber;

(AP傳到軸突末梢，鈣通道開(kāi)放，鈣內(nèi)流;)ReleaseanddiffusionofAch.

(Ach釋放、擴(kuò)散)Achcombinedwiththechemically-gatedionchannelinend-platemembrane,thechannelisopened,Na+rushtotheinside/K+diffusetotheoutside,thisprocessarousesendplatepotential;(Ach與終板膜化學(xué)門(mén)控通道結(jié)合，正離子通道打開(kāi),鈉內(nèi)流為主/鉀外流，還有鈣內(nèi)流，引起終板電位).Theendplatepotentialdiffusionleadtodepolarizationofcellmembraneandreachtothresholdpotential,thisprocessarousesAP;

(后者擴(kuò)布使肌細(xì)胞膜去極化達(dá)閾電位，引發(fā)AP)Achdecomposition(Ach分解)

Transmitterdecomposition(遞質(zhì)分解)(1)Endplatepotential,EPP(終板電位)about50mvandminiatureendplatepotential,MEPP(小終板電位)about

0.5mv(2)QualitativerelationbetweenNimpulseandmusclecontraction

(N沖動(dòng)與肌肉收縮在量上的關(guān)系)1:1Neuromuscularjunctionfatigue(神經(jīng)肌肉接點(diǎn)疲勞)(3)Terminationofexcitation(興奮的終止)acetylcholinesterase(乙酰膽堿酯酶);eserine毒扁豆堿(依色林);curare(箭毒)(4)Reversalpotential逆轉(zhuǎn)電位(-15mv)Fig3-12Ach-正離子通透性增加當(dāng)膜電位處于極化狀態(tài)時(shí)：Ach引起內(nèi)向電流（鈉內(nèi)流>鉀外流)當(dāng)Ach引起的鈉內(nèi)流＝鉀外流時(shí)的膜電位即凈電流為零－逆轉(zhuǎn)電位當(dāng)膜電位處于去極化狀態(tài)時(shí)：Ach引起外向電流（鉀外流>鈉內(nèi)流)3.TheCharactersofExcitationTransmission

OnNeuromuscularJunction

(神經(jīng)肌肉接點(diǎn)興奮傳遞的特點(diǎn))(1)Unidirectionaltransmission(單向傳導(dǎo))Fig.3-4(2)Synapsedelay(time)(突觸延擱)(3)Susceptibility(易感性)1.enter“Chapter4Excitationandcontractionofmuscle(肌肉的興奮與收縮)”

2.backto“introduction”

3.over

4.backtomenuChapter4ExcitationandContraction

ofMuscle

(肌肉的興奮與收縮)

skeletalmuscleMusclecardiacmusclestriatedmusclesmoothmuscle

Section1StructureofSkeletalmuscleandSubmicroscopicStructureofMyofibril(骨骼肌的結(jié)構(gòu)與肌原纖維的亞顯微結(jié)構(gòu))骨骼肌心肌平滑肌橫紋肌1.MinuteStructureofSkeletalMuscle

（骨骼肌的微細(xì)結(jié)構(gòu)）

Fig4-1

(1)Myofibrilandsarcomere

(肌原纖維與肌小節(jié))

Skeletalmuscle:nmusclefiber+C.T(骨骼肌)(n肌纖維+C.T)Musclefiber:nmyofibril+other(肌纖維)(n肌原纖維+其它)Myofibril(肌原纖維):

Transversestriation(橫紋)lightband(明帶)Zline(Z線)；

Anisotropicband(Aband)暗帶(A帶)Hband(H帶)；

Thickfilament+thinfilament(粗肌絲+細(xì)肌絲);Sarcomere(肌小節(jié)):

1/2lightband(1/2明帶)；

Anisotropicband(暗帶)；

1/2lightband(1/2明帶)

Myofibril

(肌原纖維)

Thickfilament+thinfilament

(粗肌絲+細(xì)肌絲)Sarcomere:

(肌小節(jié))1/2lightbandAnisotropicband1/2lightband(2)ThickMyofilamentandThinMyofilament(粗肌絲與細(xì)肌絲)

Thickmyofilament(粗肌絲):

Madeupofmyosin(肌球蛋白)Thinmyofilament(細(xì)肌絲)

：

Actin(肌動(dòng)蛋白)-----nglobular---fibreshapeTropomyosin(原肌球蛋白)Troponin(肌鈣蛋白)Fig4-7,4-11(3)SarcotubularSystem(肌管系統(tǒng))Transversetubesystem(橫管系統(tǒng)):

Myocytemembraneinvagination(Zlinelevel)

肌細(xì)胞膜內(nèi)陷（Z線處）Ductuslangitudinalssystem(縱管系統(tǒng)):

Smoothsurfacedendoplasmicreticulum(SER)(滑面內(nèi)質(zhì)網(wǎng))Lateralsac(側(cè)囊)/terminalcisterna(終末池)

Tripletube(三聯(lián)管):

Fig4-14Thefunctionofsarcotubular(肌管的作用):Transversetube(橫管):

TransmitAPtothedeeppartofmyocyte(傳導(dǎo)AP至肌細(xì)胞深部)Ductuslangitudinals(縱管):

Reserve,release,accumulatecalcium(貯存、釋放、聚積鈣)Tripletube(三聯(lián)管):

Thestructurebasisofexcitation-contractioncoupling(E-Ccoupling)(興奮-收縮耦聯(lián)的結(jié)構(gòu)基礎(chǔ))Section2ThePrincipleofMuscleContraction

(肌肉收縮的原理)

1.Proofs:(1)Thechangesoflightandanisotropicbandwithmusclecontractionandrelaxation.

(肌肉收縮與舒張時(shí)明暗帶的變化)Fig4-8(2)Theoverlappinggradeofthickfilamentandthinfilamentarerelatedtothestrainthatgeneratedbysarcomerecontraction(粗細(xì)肌絲的重疊程度與肌小節(jié)收縮產(chǎn)生的張力有關(guān))

3.652.25force

Thickfilament(粗肌絲)1.6

（無(wú)突起0.2）

Thinfilament(細(xì)肌絲)

2.05 Fig4-93.652.MyofilamentSlidingTheory

(肌絲滑行學(xué)說(shuō))

(1)BasicContent:

肌膜AP經(jīng)橫管傳至三聯(lián)管，終末池釋放鈣致肌漿鈣增多，肌鈣蛋白與鈣結(jié)合而變構(gòu)，原肌球蛋白變構(gòu)、解抑，橫橋與肌動(dòng)蛋白結(jié)合并分解ATP，橫橋內(nèi)扭、解離、復(fù)位、再結(jié)合而不斷循環(huán)將細(xì)肌絲拖向A帶中心，肌小節(jié)縮短（收縮）；鈣泵將鈣泵入終末池，肌漿鈣減少，肌鈣蛋白脫下鈣而變構(gòu)，原肌球蛋白變構(gòu)并重建阻抑，細(xì)肌絲滑回原位（舒張）。Cross-bridgeanditsfunction(橫橋及其作用)

Fig4-10Section3Excitation-contractionCoupling(興奮—收縮藕聯(lián))Definition:

Theseriesofeventslinkingmuscleexcitation(thepresenceofanactionpotential)tomusclecontraction(filamentslidingandsarcomereshortening)(肌膜上的AP觸發(fā)肌纖維收縮的一系列過(guò)程)Structurebasis:tripletube(三聯(lián)管)Process：

1.Excitationtransmittothedeepofmusclefiberthroughcrossbridge(電興奮通過(guò)橫管傳到肌纖維深部)

2.Triple

tubetransmitinformation

（三聯(lián)管傳遞信息）

3.Calciumisreleasedbysarcoplasmicreticulum

肌漿網(wǎng)對(duì)鈣的釋放）4.Myofilamentslide,musclecontract.

（肌絲滑行，肌肉收縮）5.Calciumisaccumulatedbysarcoplasmicreticulumagain,musclerelax.

（肌質(zhì)網(wǎng)對(duì)鈣的再聚積，肌肉舒張）Section4IsotonicContractionandIsometricContractionofMuscle

(肌肉的等張收縮與等長(zhǎng)收縮)Isotoniccontraction(等張收縮):

Amusclecontractioninwhichmuscletensionremainsconstantasthemusclefiberchangesitslength(肌肉收縮時(shí),肌肉的張力不發(fā)生變化,肌肉的長(zhǎng)度發(fā)生變化的收縮)Characters(特點(diǎn))：肌肉張力的增加在前，肌肉長(zhǎng)度的縮短在后，肌肉縮短一旦開(kāi)始，張力不再增加。Isometriccontraction

(等長(zhǎng)收縮):

Amusclecontractioninwhichthedevelopmentoftensionoccursatconstantmusclelength(肌肉兩端固定,收縮時(shí)肌肉的長(zhǎng)度幾乎不發(fā)生變化,肌肉的張力發(fā)生變化的收縮)Characteristic:

長(zhǎng)度不變，收縮的速度和長(zhǎng)度為零，產(chǎn)生的張力最大。Preload前負(fù)荷等張收縮等長(zhǎng)收縮Section5TheRelationBetweenIntensity,FrequencyofStimulusandMuscleContraction

(刺激強(qiáng)度、刺激頻率與肌肉收縮的關(guān)系)1.TheRelationBetweenStimulusIntensityandMuscleContraction(刺激強(qiáng)度和肌肉收縮的關(guān)系)Thresholdintensity(閾強(qiáng)度):Maximalintensity(頂強(qiáng)度):

Theminimalstimulusintensitywhichcancausemaximalmusclecontraction.(引起肌肉組織作最大收縮反應(yīng)的最小刺激強(qiáng)度

)Motorunit(運(yùn)動(dòng)單位)：

Itismadeupofamotorneuronandthefiberthatdominatedbyefferentfiber(由一個(gè)運(yùn)動(dòng)神經(jīng)元及其傳出纖維所支配的肌纖維組成)2.TheRelationBetweenStimulusFrequency andContractionResponse(刺激頻率和收縮反應(yīng)的關(guān)系)

Singlestimulus(單刺激):The

individualtwitchcontractioncausedbystimulusoflowfrequency(單收縮:肌肉受低頻刺激而出現(xiàn)的獨(dú)立收縮)singletwitch(單收縮):

Latentperiod(潛伏期)Contractionperiod(收縮期)Relaxationperiod(舒張期)

sContinuousstimulus(連續(xù)刺激):

compositecontraction/summationofcontraction(復(fù)合收縮/收縮融合)Incompletetetanus(不完全強(qiáng)直收縮)Completetetanus(完全強(qiáng)直收縮)

Section6TheCharactersofStructureandFunctionofSmoothMuscle

(平滑肌的結(jié)構(gòu)與機(jī)能特點(diǎn))1.TheStructureCharactersofSmoothMuscle(平滑肌的結(jié)構(gòu)特點(diǎn))Small,fusiformbody(小,呈梭形)Notransversestriation(無(wú)橫紋)2.TheTypesofSmoothMuscle(平滑肌的類型)(1)Multi-unitsmoothmuscle(多單位平滑肌):Itisalsonamedmotorunitsmoothmuscle.(又叫運(yùn)動(dòng)單位平滑肌)

Characters:

各自獨(dú)立,且每個(gè)肌纖維均接受一個(gè)或多個(gè)神經(jīng)元的傳出神經(jīng)末梢支配,幾乎無(wú)自發(fā)收縮活動(dòng),且一般不產(chǎn)生AP. (2)Single-unitsmoothmuscle(一單位平滑肌):Itisalsonamedvisceralsmoothmuscle(又叫內(nèi)臟平滑肌)Characters:

具有自發(fā)性收縮,細(xì)胞間的連接多為縫隙連接,各細(xì)胞可通過(guò)細(xì)胞間的電藕聯(lián)進(jìn)行同步性活動(dòng),對(duì)牽拉刺激較敏感.3.ElectricActivityofSmoothMuscle(平滑肌的電活動(dòng))(1)Multi-unitsmoothmuscle(多單位平滑肌):

Itdoesn’tgenerateAPgenerally(一般不產(chǎn)生AP).

(2)Single-unitsmoothmuscle(一單位平滑肌):①Basicelectricrhythm,BER(基本電節(jié)律):Self-inducedelectricalactivityofthedigestive-tractsmoothmuscle(有節(jié)律地反復(fù)進(jìn)行的去極化和復(fù)極化活動(dòng))②AP:PeakshapeortheAPwithplateau(鋒形或有平臺(tái)的AP)

Mechanism:

有鈉內(nèi)流但主要是鈣內(nèi)流4.ContractionActivityofSmoothMuscle

(平滑肌的收縮活動(dòng))

(1)Latentperiodislong(潛伏期長(zhǎng))Theintersticeofneuromuscularjunctionisbig;sarcoplasmicreticulumisn’tadvanced(神經(jīng)肌接點(diǎn)間隙大;肌質(zhì)網(wǎng)不發(fā)達(dá))

(2)Contractionperiodislong(收縮期長(zhǎng))ThecapacityofCapumpislow.(鈣泵能力低)(3)Velocityisslow;thetensityislow;myofilamentandATPCParefew.(速度慢,緊張度低肌絲少,ATP、CP少)5.PhysiologicalCharactersofVisceralSmoothMuscle(內(nèi)臟平滑肌的生理特性)

(1)Automaticity(自動(dòng)性)(2)Sensitivitytoinsideandoutsideenvironment(對(duì)內(nèi)外環(huán)境變化敏感)(3)Excitabilityislow;contractionisslow.(興奮性較低,收縮緩慢)(4)Extensibility(伸展性)(5)Toniccontraction(緊張性收縮)Digestion(消化):Thebreak-downprocesswherebythestructurallycomplexfoodstuffsofthedietareconvertedintosmallerabsorbableunitsbytheenzymesproducedwithinthedigestivesystem(食物在消化道內(nèi)被分解為小分子物質(zhì)的過(guò)程)

Mechanicaldigestion(機(jī)械性消化)Chemicaldigestion(化學(xué)性消化)

Absorption(吸收):Theprocessthatthesmallerabsorbableunitsofdigestiongetacrossthealimentarytractmucosaandcomeintobloodorlymph.(食物經(jīng)消化后通過(guò)消化道粘膜進(jìn)入血液或淋巴的過(guò)程)Section1StructureofDigestiveTract

(消化管的結(jié)構(gòu))Intracellulardigestion(胞內(nèi)消化)Extracellulardigestion(胞外消化)

1.HumanDigestiveTract(人的消化管)

粘膜層：上皮上皮下層粘膜肌層粘膜下層:C.T組織結(jié)構(gòu)(Submucouslayer)

環(huán)行肌胃部是三層

Smoothmuscle

內(nèi)斜,中環(huán),外縱縱行肌漿膜:C.T(Serousmembrane)

(Tissuestructure)(Mucouslayer)2.TheInnervationofDigestiveTract

(消化管的神經(jīng)支配)

ExtrinsicNS&IntrinsicNS

CNS肌間N叢粘膜下N叢R平滑肌分泌細(xì)胞內(nèi)分泌細(xì)胞血管交.副交N交.副交N局部Sympatheticnerve(交感N):

Thesubdivisionoftheautonomicnervoussystemthatdominatesin“fight-or-flight”emergencyorstressfulsituationsandperparesthebodyforstrenuousphysicalactivity.(源自T5~T10&L1~L2在腹神經(jīng)節(jié)和腸系膜上下N節(jié)換元)

交感NsympatheticnerveNE胃腸平滑肌血管平滑肌消化腺運(yùn)動(dòng)及分泌內(nèi)在N元

副：延髓背核疑核

迷走N盆NS2-4運(yùn)動(dòng)及分泌內(nèi)在N元胃腸平滑肌血管平滑肌消化腺M(fèi)yentericplexus(肌間N叢)Submucousplexus(粘膜下N叢)Intrinsicplexus(內(nèi)在N叢)：

包括感覺(jué)、中間、運(yùn)動(dòng)神經(jīng)元構(gòu)成一個(gè)完整且相對(duì)獨(dú)立的整合系統(tǒng)胃腸運(yùn)動(dòng)及分泌Section2TheMovementandRegulationofDigestiveTract

(消化管的運(yùn)動(dòng)及調(diào)節(jié))

Themovementofdigestivetract(消化道的運(yùn)動(dòng)):

Mastication(咀嚼)

Deglutition(吞咽)

Gastrointestinalmovement(胃腸運(yùn)動(dòng))Reflex(反射):Anyresponsethatoccursautomaticallywithoutconsciouseffort.(在NS的參與下對(duì)刺激的規(guī)律性應(yīng)答)

Reflexarc(反射弧):Thecomponentsofareflexarcincludeareceptor,afferentpathway,integratingcenter,efferentpathway,andeffector.(感受器傳入NN中樞傳出N效應(yīng)器)1.Gastricmovement(胃的運(yùn)動(dòng))(1)Receptiverelaxation(胃的容受性舒張)Definition:

foodstimulatethereceptorsinpharynxandesophagus,throughvagusnervearouserelaxationoffundusandbodyofstomachmuscle.(食物刺激咽、食管等處感受器經(jīng)迷走神經(jīng)反射性引起胃底、胃體肌舒張)

significance肽類纖維？(2)Toniccontraction(緊張性收縮)(3)Peristalsis(蠕動(dòng))GastricBER(胃的基本電節(jié)律):Itstemsfromlongitudinalmuscleofgreatercurvature,3~5timesperminutes,amplitudeisabout5~15mv.(起源于胃大彎的縱行肌層，每分鐘3~5次，振幅約5~15mv)

Function

ofperistalsis(蠕動(dòng))

：①Leadtoamplemixingofchymeanddigestivejuice,thisisfacilitatedforchemicaldigestion.

使食糜與消化液充分混合，利于化學(xué)性消化②Millfood(mechanicaldigestion)

磨碎食物(即機(jī)械性消化)③Pushchyme

推進(jìn)食糜2.GastricEmptyingandItsRegulation

(胃的排空及其控制)Definition:Theprocessthatfoodenterintoduodenumfromstomach.(食物由胃排入12指腸的過(guò)程)

(1)胃排空(gastricemptying)

Emptyingvelocity(排空速度)：Sugar>protein>fat;Sparse,thin,isosmoticquick(稀、細(xì)、等滲──快)(反之則慢)(2)Regulationofgastricemptying

(胃排空的調(diào)控)

Entogastricfactorsaccelerateemptying(胃內(nèi)因素促進(jìn)排空)：①Entogastricfood（Nr）(胃內(nèi)食物)②Gastrin（Hr）(胃泌素)

Factorsofduodenuminhibitemptying(12脂腸因素抑制排空)：

①Gastrointestinalreflex（Nr）(腸胃反射)②Enterogastrone（Hr）(腸抑胃素)Emptyingprocess

(排空過(guò)程)：

Entogastricfood(胃內(nèi)食物)

emptyingstopped(排空停止)motilityofthestomach(胃運(yùn)動(dòng))↑

胃運(yùn)動(dòng)↓幽門(mén)括約肌舒張幽門(mén)括約肌收縮胃內(nèi)壓>12指腸內(nèi)壓N(腸胃反射)H(腸抑胃素)Nr.Hr排空腸內(nèi)胃酸被中和食物被消化吸收3.Themovementsofsmallintestine

(小腸的運(yùn)動(dòng))(1)Toniccontraction(緊張性收縮)

Functions：

①M(fèi)aintainbasicpressure(維持基礎(chǔ)壓力)②Thebasisofmovements(是腸運(yùn)動(dòng)的基礎(chǔ))③Fixandkeepshapeofsmallintestine(維持小腸的位置形狀)

(2)Segmentationcontraction

(分節(jié)運(yùn)動(dòng))

Functions：①

Itcanleadtoamplemixingofchymeanddigestivejuice,thisisfacilitatedforchemicaldigestion.(使食糜與消化液充分混合，利于化學(xué)性消化)②Itcanaccelerateclosecontactofchymeandintestinalwall,thisisfacilitatedforabsorption.(使食糜與腸壁緊密接觸，利于吸收)③Itcanpressintestinalwall,acceleratebloodandlymphcircumfluence.(擠壓腸壁而促進(jìn)血液、淋巴回流)(3)Peristalsis(蠕動(dòng))Peristalsisfunction:

pushchyme(推進(jìn)食糜)(4)Largeintestinalmovementanddefecation

(大腸運(yùn)動(dòng)和排便)

①Themovement

formsoflargeintestine

(大腸運(yùn)動(dòng)形式)