医学机能实验学报告蛙心灌流英文

Laboratory Report本组承诺本实验报告原创，绝无抄袭!组员Effects ofchemical substanceson the activity of theisolated toad heart[Purpose]To observe the effectsof threeions sodium,potassium,calcium andtwochemical substancesacetylcholine andadrenaline on theactivity of thetoad heart invitro.【Animal]Toad.【Method]

1.Preparation of the isolatedheartTake atoad,after destoryingits brain and spinalcord,fix iton thetoadplate onback,open thethoracic cavity,cut pericardiumto exposethe heart.Then,put oneline underaorta makinga slipknotat thesuperior extremityof the left aorta,is usedto towwhen intubation.Shear areversed“Vshaped incisionwith ophthalmologicalscissors atroot ofleftaorta,insert apropercannula oftoadheartthat containsRingers solution into thearterycone from the cutposition.Then make a deadknot.Hold upthe cannulagentlyto raiseheart,makealigation atthe boundaryof thevenous sinusandthe venacava.Finally,cut offaortas andthe venacava,dissociate theheartfrom thetoad.

2.Apparatus installmentAtfirst,clamp thecanula with a woodentube clip,then thewooden tubeclipis fixedontheiron bracketby adouble caveclamp.Clamp thetip ofthe heart atventricle diastolewithatoadheartclip thatis linkedwith alongline in the otherend,then linkthe lineto theadaptive bridgein thetensiontransducer.Regulate theposition ofthe pulleyso thatthe tensilityofline isappropriate.

3.Observation items

1.Record the normal curveoftherelaxation andconstriction oftheisolated heart.

2.After the Ringers solutionin cannulais allreplaced by

0.65%Nacl,observe thechange ofthe heartbeat.

3.Take outthe Nacl,wash itseveral timesrepearedly with fresh Ringerssolution.When the heartbeat recoversto normaladd2%Cach2drops tothe Ringerssolutionin the cannula,observe thechange ofthe heartbeat.

4.Take outthe Ringers solution includingCack,wash itseveral timesrepearedlywith freshRingers solution.After thecurve recoverto normal,add1%KCL2drops inthe Ringers solutionin thecannula,observe thechange ofthe heartbeat.

5.Take outthe Ringers solution includingKcl,wash itseveral timesrepearedly withfreshRingers solution.After thecurve recoverto normal,add1:1000adenaline2dropsin theRingerssolutionin thecannula,observe thechange ofthe heartbeat.

6..Take outtheRingerssolution includingadenaline,wash itseveral timesrepearedlywithfreshRingerssolution.After thecurve recoverto normal,add1:1000ACh2drops in theRingerssolutioninthecannula,observe thechangeoftheheartbeat.【Result]Contraction scopeContraction frequencynormalK+Ca2+Na+T TADJJAChThe imageis inthe last.[Discussion]l.The normalheart rhythmactivities requirea suitableenvironment,changes intheenvironment hasa directimpact onthenormalactivityoftheheart.This experimentinfrog heartof perfusionfluid tojoin someofthematerial changeintheenvironment ofcardiacactivity,observethechanges incardiac events.

2.Cardiac musclecells classificationContractiliExcitabili Conductiviautorhythmicityty tytynon-autorhyth Has Has HasDoesnt havemiccellautorhythmic DoesntHasHasHascell have

3.Fast reaction cell Atria,ventricular,Purkinje cells:mainly consistsof sodiumchannel is activated,Na fastflow triggeredaction potential.Slow reaction cell sinuscells,atrioventricular junctioncell:mainly byslow calciumchannelisactivated,Ca raisesaction potentialsinthestream,go tothe veryslow

4.Myocardial cellphysiological characteristics:1Electrophysiological characteristics:self-discipline,excitability,conductive2Machinery physiologicalcharacteristics:shrinkage

5.Factors affectingcardiac cellImpact factorof cardiomyocyteexcitabilityventricular self-discipline sinuscells Impactmyocardial cellmyocytesconductive factorsatrioventricularjunction cells

1.State ofNa channell.diamete

2.Difference Restingpotential

2.depolarization amplitudeandlevel and threshold potential

1.Depolarization speedof4phase speedof0phase

2.Difference betweenmaximum

3.The excitabilityof adjacentbipolarvoltage levelandthresholdparts ofthe filmMyocardialcell excitation-contraction couplingprocesses requiredbythe Ca2+to transitfromtheextracellular fluid,excitement,cellmembranes Ca2+channel,therefore:extracellular Ca2+concentrationtcell excitedinner flowCa2+tmyocardial contractilityt,and viceversa.

6.1%KC1Moderate andhigh potassium:Extracellular K+,K+and Ca2+inacompetitive inhibition of cell-membraneK+inhibitors onCa2+transportenter theintracellularCa2+Icardiac excitation-contraction withtheprocess ofweakeningmyocardial contractilityI1t[K+]K+concentration gradientreduces betweeninside andoutsiderestingpotential absolutevalue decreaseexcitatoryt2t[K+]cell membrane permeability increaseson K+K+channel inactivatingspeed Iautomaticdepolarization speed1autorhythmicity!3t[K+]cell membranepermeability increaseson K+K+outflow increasemaximumrepolarization potentialfautorhythmicity!4t[K+]inhibitionofinternal flowby Ca2+depolarizationamplitude andspeedof0phase reduceconductivitylower.Severe highpotassium:[K+]f tRPINa+channel inactivationexcitatorylose.

7.2%CaCl2Na+and Ca2+in outermembrane havecompetitive inhibitionConcentration ofextracellularCa2+fCa2+flow fwhen cellsexcitemyocardial contractility tFastreactioncell:high Ca2+inhibit Na+inner flow0periodDepolarisation speedand magnitudedownwardconductivity ISlowreactioncell:high Ca2+Ca2+enter into cells easily,Ca2+flow increase0period Depolarisationspeed increaseconductivityf

8.

0.65%NaCIExtracellular Ca2+1Ca2+flow Xin2phaseCytosolicCa2+concentration1myocardial contractility1[Ca2+]1Ca2+inner flowreduction depolarisationslows in

8.phaseconductive1[Ca2+]1Ca2+is noteasy toenter thecellsautomaticdepolarization speedis slowin4phaseautorhythmicity X

9.ADAdrenaline conbinesmyocardial cell membrane ofB-1receptors-myocardial cells一and sarcoplasmicreticulum membranepermeability ofCa2+increasessarcoplasmic Ca2+concentrationincreases myocardialcontractility T.lO.AChAcetylcholine conbinesM receptorin myocardial cellmembrane—myocardialcellmembranepermeabilityof Kchannel一promoting TK+outflow1Sinoatrial nodecells K+outflow Twhen cellsrepolarizemax bipolarvoltage levelTautorhythmicity12K+outflow Twhen cellsrepolarize2and3phase ofAPshorterCa2+intocells1myocardial contractilityl3Acetylcholine caninhibit Ca2+channel directlyCa2+，channel flow1myocardialcontractility.[Conclusion]

1.Infusion containingpotassium ions,with specialattention todetect theconcentrationof potassiumions.

2.If thetoad!s heartbeat weak,AD canbe usedto enhancetheheartbeat.

3.Control variousions concentration,AD andACh volumeto adjustthe bodysinternalenvironment tomaintain homeotasis.。