第四篇血液循环2生理学.ppt

ChapterIVbloodcirculation,生理学PHYSIOLOGY,内容简介：,心脏的生物电活动心脏生理(CardiacPhysiology)心脏的泵血功能血管生理（vascularphysiology)心血管活动的调节,SectionTwo,Mechanismofheartpump,SectionOverview,Cardiaccircle;Processofheartpumpingblood;Estimationoffunctionofheartpumping;Cardiacreserve;Regulationofheartpumping;,Heartrate,(HR),Thetimesofheartbeatinaminute.Normalvalue:60100beats/minHR100b/m-TachycardiaHRventriclesatriaValve:A-Vclosed,SemilunarclosedV-ventricles:notchangeBloodcurrentdirection:notflowCharacteristics:ventricularpressurerisesdrastically,Isovolumetricventricularcontraction,RapidVentricularEjection,Duration:0.1sPressure:ventriclesaortaValve:A-Vclosed,SemilunaropenedV-ventricles:decreaseBloodcurrentdirection:bloodejectedintoaortarapidlyCharacteristics:P-ventriclesreachpeakEjectingvolumeis2/3ofthetotalejecting,VentricularSystole,ReducedVentricularEjection,Duration:0.15sPressure:ventriclesventriclesatriaValve:A-Vclosed,SemilunarclosedV-ventricles:notchangeBloodcurrent:notflowCharacteristics:ventriclespressuredecreasedrapidly,Isovolumetricventricularrelaxation,VentricularDiastole,Duration:0.11sPressure:aortaventriclesventriclesatriaventriclesValve:A-Vopened,SemilunarclosedV-ventricles:increasesBloodcurrent:atriaejectingbloodtoventriclesCharacteristic:FinalphaseofventriclesfillingAdds10%-30%toventriclesvolume,Atrialsystole,THEPRESSURE-VOLUMELOOP,充盈期,等容收缩期,射血期,等容舒张期,CardiacCycle,AtrialSystole,MitralCloses,Isovolumiccontract.,Aorticopens,RapidEjection,ReducedEjection,IsovolumicRelax.,Aorticcloses,RapidVentricularFilling,Mitralopens,ReducedVentricularFilling,AtrialSystole,Summary,Thecontractionofventricularmusclesisthefundamentalreasonforthecardiacpumpingblood;Thedifferenceofpressureisthedirectpowerofcardiacpumpingblood;Theopenorcloseofthevalvesdeterminetheuni-directionalofbloodflow;左、右心室搏出量相等。,Summary,快速射血期末心室压力最大。减慢射血期内主动脉压力已高于心室内压力。减慢射血期末心室容积最小舒张末期心室容积最大。心室2/3血液充盈在快速充盈期完成，且是负压抽吸所致，1030的血量在心房收缩期完成。,RoleofatrialonHeartPumping,AccommodatingandstoringbloodfromveinFillingofventriclesdependmainlyonthediastoleofventriclesPrimarypump,TheAssessoffunctionofheartpumping,Strokevolume:isthevolumepumpedoutbyoneventriclewitheachbeat.=EDVESV=approximate125-55=70ml。Determinedbythecontractibilityofcardiacmuscle.Thestrokevolumeoftheleftventricleisthesameasthatoftherightventricle.,EDV,ESV,SV,Ejectionfraction,ThevalueisequaltothequotientbetweenthestrokevolumeandEDV.Isabout55-65(70/125)inrestingstate.EjectionfractionisrelativeconstantasSVisalwaysproportionaltoEDV.,Cardiacoutput,Cardiacoutputisthevolumepumpedoutbyeachventricleperminute.CO=SVxHRCOforthehealthyhumanadultatrest:5.25liters/min(4.5to6L/minforhealthymales)Thecardiacoutputoftheleftventricleisthesameasthatofrightventricle.Changewithbodyactivitiesandmetabolismcondition.,Cardiacindex,CardiacindexisthecardiacoutputpersquaremeterofbodysurfaceareaNormalvaluesrangefrom3.0to3.5liter/min/m2(Foranadultwithaveragesize,bodysurfacearea1.6-1.7m2)Itvarieswithage,gender,metabolicstateofthebody.,Cardiacreserve,Cardiacreserve,Cardiacreservemeanstheabilitywhichcardiacoutputcanincreasewiththedemandoforganismmetabolism.=MaximumCO-minimalCO,CardiacReserveIncluding:ReserveofSVandHRReserve,CO=SVHR,EDV-ESV,Systolicreserve,Diastolicreserve,HRreserve,增加心舒末期容积约15ml。,减小心缩末期容积约3540ml。,SourceofCardiacReserve,Systolicreserve3540ml,Diastolicreserve(15ml),HRreserve,5.RegulationofHeartPumping,Thegoal:matchCOtoneedRegulationofthestrokevolumePreloadAfterloadContractilityRegulationoftheHRNervousregulationHumoralregulation,RegulationofHeartPumping,1.TheregulationofstrokevolumeEffectofpreloadonstrokevolumeEffectofafterloadonstrokevolumeEffectofcontractilityonstrokevolume,1)Effectofpreloadonstrokevolume,Preload:肌肉收缩前所负载的负荷.决定肌肉的初长度（initiallength）。,Forcardiacmyocyte,thepreloadisusuallyconsideredtobetheend-diastolicpressure(orend-diastolicvolume),1)Effectofpreloadonstrokevolume（ventriclefunctioncurve）EDP在1215mmHg为最适前负荷。肌小节2.02.2m，粗、细肌丝处于最佳重叠，产生的张力最大。EDP在615mmHg，EDP,张力粗、细肌丝有效最佳重叠。,EDP在1520mmHg，曲线趋于平坦。静息被动张力，EDP对肌小节影响不大，张力不增加。,EDP20mmHg曲线平坦或轻度下倾，无明显的降支心肌的可伸展性较小，静息被动张力大，阻止心肌细胞过度拉长。使心肌肌小节的初长度一般不会超过2.252.30m。意义：可使心脏不致于在前负荷明显增加时出现搏出量和作功能力的下降。,2）异长自身调节（heterometricautoregulation）通过心肌细胞本身初长度的改变而引起心肌收缩强度的变化称为。,生理意义：对搏出量微小变化的精细调节，维持心室射血与静脉回流量的平衡。保持心室舒张末期压力和容积在正常范围。Itisresponsibleforthepreciseregulation,andkeepbalancebetweentheoutputsandinputsoftheheart.,3）ImportanceofHeterometricAutoregulation,Justremember:Whatgoesinmustcomeout.,5）AffectingFactorofPreload(EDV),静脉回心血量Fillingtimeofventricles.(diastoleperiod).WithHR,fillingtimeshorten.SpeedofvenousreturnDeterminedbyPeripheralVP-CVPVentricularcompliancePericarialpressureResiduevolumeafterejection(ESV),2).EffectofAfterloadonStrokeVolume,Afterload是指在肌肉开始收缩时才遇到的负荷或阻力。它不增加肌肉的初长度，但能阻碍收缩时肌肉的缩短。Insimpleterms,theafterloadiscloselyrelatedtotheaorticpressure.,APAfterloadTheventriclewillhavetogenerateincreasedpressurePeriodofisovolumiccontractionDecreasesthevelocityofcardiacfibersshorteningEjectionvelocityafterthevalveopenswillbereducedlessbloodwillbeejectedSV,question?,在整体条件下，正常人主动脉血压于80160mmHg范围内变化时，心输出量为什么并无明显改变?BPSV减少左心室残余血量增多左心室EDV，通过异长自身调节使心肌收缩增强SV生理意义：在动脉血压升高的一定范围内，仍可维持接近正常的心输出量。,3).EffectofContractilityonStrokeVolume,心肌不依赖于负荷而能改变其力学活动（收缩的强度和速度）的内在特性。又称为心肌的变力状态（intropicstate）。,等长自身调节（homeometricautoregulation）：通过肌肉内部机能状态（心肌收缩能力）的改变而实现的泵血功能调节,凡是影响到兴奋收缩耦联过程的各个环节均可影响心肌的收缩力；如：活化的横桥数目，ATP酶的活性；胞内Ca2+的浓度等。,等长自身调节,Affectingfactorsofcontractility,（1）活化横桥数胞浆中的Ca2+浓度：儿茶酚胺Ca2+与肌钙蛋白的亲合力：茶碱（钙增敏剂）（2）横桥ATP酶活性甲状腺激素和体育锻炼,2.Ther