血液循環(huán)2生理學(xué)課件

ChapterIVbloodcirculation

PHYSIOLOGY內(nèi)容簡介：

心臟的生物電活動(dòng)心臟生理

(CardiacPhysiology)

心臟的泵血功能

血管生理（vascularphysiology)

心血管活動(dòng)的調(diào)節(jié)SectionTwoMechanismofheartpumpHeartrate,(HR)

Thetimesofheartbeatinaminute.Normalvalue:60~100beats/minHR>100b/m---TachycardiaHR<60b/m---BradycardiaCardiaccircleDefinition:心臟一次收縮和舒張所構(gòu)成的機(jī)械活動(dòng)周期。Consistingofcontractionorsystole,relaxationordiastole.Thereisasequenceofsystoleanddiastoleoftheatriumandventricle.心房收縮是一次心動(dòng)周期的開始。ContractionofventricleContractionofatriumWholeheartdiastolerelaxationofventriclecardiaccycleTheprocessofheartpumping

Ventricularsystole:isovolumiccontractionphase（1）ejectionphase:rapidejectionphase（2）reduceejectionphase（3）

Ventriclesdiastole:

isovolumicrelaxation（4）

fillingphase:rapidfillingphase（5）reducedfillingphase（6）atrialsystole（7）VentricularSystoleDuration:0.05sPressure:aorta>ventricles>atriaValve:A-Vclosed,SemilunarclosedV-ventricles:notchangeBloodcurrentdirection:notflowCharacteristics:ventricularpressurerisesdrasticallyIsovolumetricventricularcontractionRapidVentricularEjectionDuration:0.1sPressure:ventricles>aortaValve:A-Vclosed,SemilunaropenedV-ventricles:decreaseBloodcurrentdirection:bloodejectedintoaortarapidlyCharacteristics:P-ventriclesreachpeakEjectingvolumeis2/3ofthetotalejectingVentricularSystoleReducedVentricularEjectionDuration:0.15sPressure:ventricles<aortaValve:A-Vclosed,SemilunaropenedV-ventricles:decreaseBloodcurrentdirection:bloodejectedintoaortaslowlyCharacteristics:Ejectingreliesonthemomentum（動(dòng)量）ofbloodVentricularSystoleVentricularDiastoleDuration:0.06~0.08sPressure:aorta>ventricles>atriaValve:A-Vclosed,SemilunarclosedV-ventricles:notchangeBloodcurrent:notflowCharacteristics:ventriclespressuredecreasedrapidlyIsovolumetricventricularrelaxationVentricularDiastoleDuration:0.11sPressure:aorta>ventricles<atriaValve:A-Vopened,SemilunarclosedV-ventricles:increasesBloodcurrent:ventriclesfillwithbloodfromatriarapidlyCharacteristics:fillingvolumeis2/3ofthetotalfillingRapidventricularfillingVentricularDiastoleDuration:0.22sPressure:aorta>ventricles<atriaValve:A-Vopened,SemilunarclosedV-ventricles:increasesBloodcurrent:ventriclesfillwithbloodfromatriaslowly.ReducedventricularfillingVentricularDiastoleDuration:0.1sPressure:aorta>atria>ventriclesValve:A-Vopened,SemilunarclosedV-ventricles:increasesBloodcurrent:atriaejectingbloodtoventriclesCharacteristic:

Finalphaseofventriclesfilling

Adds10%-30%toventriclesvolumeAtrialsystole

時(shí)相時(shí)間(s)壓力變化二半尖月瓣瓣心內(nèi)血流心室容積

心室收縮期等容收縮期0.05室內(nèi)壓迅速上升，房內(nèi)壓<室內(nèi)壓<主A壓關(guān)關(guān)無不變快速射血期0.10房內(nèi)壓<室內(nèi)壓>主A壓關(guān)開室→主動(dòng)脈(快)縮小減慢射血期0.15房內(nèi)壓<室內(nèi)壓≤主A壓關(guān)開室→主動(dòng)脈(慢)縮小

心室舒張期等容舒張期0.07室內(nèi)壓迅速上升，房內(nèi)壓<室內(nèi)壓<主A壓關(guān)關(guān)無不變快速充盈期0.11房內(nèi)壓>室內(nèi)壓<主A壓開關(guān)房→室(快)增大減慢充盈期0.22房內(nèi)壓>室內(nèi)壓<主A壓開關(guān)房→室(慢)增大心房收縮期0.10房內(nèi)壓>室內(nèi)壓<主動(dòng)脈壓開關(guān)房→室增大SummaryThecontractionofventricularmusclesisthefundamentalreasonforthecardiacpumpingblood;Thedifferenceofpressureisthedirectpowerofcardiacpumpingblood;Theopenorcloseofthevalvesdeterminetheuni-directionalofbloodflow;左、右心室搏出量相等。Summary快速射血期末心室壓力最大。減慢射血期內(nèi)主動(dòng)脈壓力已高于心室內(nèi)壓力。減慢射血期末心室容積最小舒張末期心室容積最大。心室2/3血液充盈在快速充盈期完成，且是負(fù)壓抽吸所致，10－30％的血量在心房收縮期完成。RoleofatrialonHeartPumpingAccommodatingandstoringbloodfromveinFillingofventriclesdependmainlyonthediastoleofventriclesPrimarypumpTheAssessoffunctionofheartpumpingStrokevolume:

isthevolumepumpedoutbyoneventriclewitheachbeat.=EDV–ESV=approximate125-55=70ml。Determinedbythecontractibilityofcardiacmuscle.Thestrokevolumeoftheleftventricleisthesameasthatoftherightventricle.

EDVESVSVEjectionfractionThevalueisequaltothequotientbetweenthestrokevolumeandEDV.Isabout55-65％(70/125)

inrestingstate.EjectionfractionisrelativeconstantasSVisalwaysproportionaltoEDV.CardiacoutputCardiacoutputisthevolumepumpedoutbyeachventricleperminute.CO=SVxHRCOforthehealthyhumanadultatrest: 5.25

liters/min(4.5to6L/minforhealthymales)Thecardiacoutputoftheleftventricleisthesameasthatofrightventricle.Changewithbodyactivitiesandmetabolismcondition.CardiacindexCardiacindexisthecardiacoutputpersquaremeterofbodysurfaceareaNormalvaluesrangefrom3.0to3.5liter/min/m2(Foranadultwithaveragesize,bodysurfacearea1.6-1.7m2)Itvarieswithage,gender,metabolicstateofthebody.CardiacreserveCardiacreserveCardiacreservemeanstheabilitywhichcardiacoutputcanincreasewiththedemandoforganismmetabolism.=MaximumCO-minimalCOCardiacReserveIncluding:

ReserveofSVandHRReserveCO=SVHREDV-ESVSystolicreserveDiastolicreserveHRreserve增加心舒末期容積約15ml。減小心縮末期容積約35~40ml。SourceofCardiacReserveSystolicreserve35~40mlDiastolicreserve(~15ml)HRreserve5.RegulationofHeartPumping

Thegoal:matchCOtoneedRegulationofthestrokevolumePreloadAfterloadContractilityRegulationoftheHRNervousregulationHumoralregulationRegulationofHeartPumping1.TheregulationofstrokevolumeEffectofpreloadonstrokevolumeEffectofafterloadonstrokevolumeEffectofcontractilityonstrokevolume1)．EffectofpreloadonstrokevolumePreload:肌肉收縮前所負(fù)載的負(fù)荷.決定肌肉的初長度（initiallength）。Forcardiacmyocyte,thepreloadisusuallyconsideredtobetheend-diastolicpressure(orend-diastolicvolume)1)Effectofpreloadonstrokevolume（ventriclefunctioncurve）①EDP在12~15mmHg為最適前負(fù)荷。肌小節(jié)2.0~2.2μm，粗、細(xì)肌絲處于最佳重疊，產(chǎn)生的張力最大。②EDP在6~15mmHg，EDP,張力粗、細(xì)肌絲有效最佳重疊。③EDP在15~20mmHg，曲線趨于平坦。靜息被動(dòng)張力，EDP對肌小節(jié)影響不大，張力不增加。

④EDP>20mmHg曲線平坦或輕度下傾，無明顯的降支心肌的可伸展性較小，靜息被動(dòng)張力大，阻止心肌細(xì)胞過度拉長。使心肌肌小節(jié)的初長度一般不會超過2.25~2.30μm。意義：

可使心臟不致于在前負(fù)荷明顯增加時(shí)出現(xiàn)搏出量和作功能力的下降。2）異長自身調(diào)節(jié)（heterometricautoregulation）

通過心肌細(xì)胞本身初長度的改變而引起心肌收縮強(qiáng)度的變化稱為~。生理意義：對搏出量微小變化的精細(xì)調(diào)節(jié)，維持心室射血與靜脈回流量的平衡。保持心室舒張末期壓力和容積在正常范圍。

Itisresponsibleforthepreciseregulation,andkeepbalancebetweentheoutputsandinputsoftheheart.3）ImportanceofHeterometricAutoregulationJustremember:"Whatgoesinmustcomeout."5）AffectingFactorofPreload(EDV)

靜脈回心血量Fillingtimeofventricles.(diastoleperiod).

WithHR,fillingtimeshorten.SpeedofvenousreturnDeterminedbyPeripheralVP-CVPVentricularcompliancePericarialpressureResiduevolumeafterejection(ESV)2).EffectofAfterloadonStrokeVolume

Afterload是指在肌肉開始收縮時(shí)才遇到的負(fù)荷或阻力。它不增加肌肉的初長度，但能阻礙收縮時(shí)肌肉的縮短。Insimpleterms,theafterloadiscloselyrelatedtotheaorticpressure.APAfterloadTheventriclewillhavetogenerateincreasedpressurePeriodofisovolumiccontraction

Decreasesthevelocityofcardiacfibers shorteningEjectionvelocityafterthevalveopenswill bereducedlessbloodwillbeejectedSVquestion?在整體條件下，正常人主動(dòng)脈血壓于80~160mmHg范圍內(nèi)變化時(shí)，心輸出量為什么并無明顯改變?BP→SV減少→左心室殘余血量增多→左心室EDV，通過異長自身調(diào)節(jié)使心肌收縮增強(qiáng)→SV生理意義：在動(dòng)脈血壓升高的一定范圍內(nèi)，仍可維持接近正常的心輸出量。3).EffectofContractilityonStrokeVolume心肌不依賴于負(fù)荷而能改變其力學(xué)活動(dòng)（收縮的強(qiáng)度和速度）的內(nèi)在特性。又稱為心肌的變力狀態(tài)（intropicstate）。

等長自身調(diào)節(jié)（homeometricautoregulation）：通過肌肉內(nèi)部機(jī)能狀態(tài)（心肌收縮能力）的改變而實(shí)現(xiàn)的泵血功能調(diào)節(jié)凡是影響到興奮收縮耦聯(lián)過程的各個(gè)環(huán)節(jié)均可影響心肌的收縮力；如：活化的橫橋數(shù)目，ATP酶的活性；胞內(nèi)Ca2+的濃度等。等長自身調(diào)節(jié)Affectingfactorsofcontractility（1）活化橫橋數(shù)胞漿中的Ca2+濃度：兒茶酚胺Ca2+與肌鈣蛋白的親合力：茶堿（鈣增敏劑）（2）橫橋ATP酶活性甲狀腺激素和體育鍛煉2.TheregulationoftheheartrateTheHRisthedeterminingfactorofcardiacoutput.HR:CO=SV×HR；

心率增快（＜160~180次/min）心率↑↑SV↓每分輸出量↑心率過快（>160~180次/min）心率↑↑↑SV↓↓↓↓每分輸出量↓心率過慢（＜40次/min）心率↓↓↓SV↑每分輸出量↓因此，一定范圍內(nèi)，HR增加，心輸出量增加，HR最適宜時(shí)，心輸出量最大。HR

的變化可以影響心肌的收縮能力HR

增快引起心肌收縮能力增強(qiáng)的現(xiàn)象，叫階梯現(xiàn)象（staircasephenomenon）。HR加快，胞內(nèi)Ca2+增高。HeartRateCardiaccycle(sec)Heartrate(beat/min)Systole(sec)Diastole(sec)401.50.41.10.80.30.51200.5