《病理生理学》课件：心功能不全.ppt

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1、心功能不全周文华宁波大学医学院whzhou@vip.163.comLearningObjectivesDiscussthedefinitionDiscusstheetiologyDiscusstheclassificationDiscussmainmechanismsDiscusstheresponseofbodytoheartfailureDiscusstheclinicalmanifestationsDiscussthetreatprinciplesQ:心脏泵功能有哪些？舒张期的充盈和收缩期的射血充盈和射血都是耗能的过程心脏的解剖特点Indepol

2、arization,fastsodiumchannelsopen,allowingarapidinfluxofsodium(positivelycharged)ionsintothecell.Asthecellvoltagepeaks,thefastsodiumchannelclosesandthecellmovesintotheearlystageofrepolarization.Thisearlyrepolarizationisfollowedbyaplateauphase,inwhichcalciumandsodiumionsslowlyente

3、rthecellthroughslowcalcium-sodiumchannels.Thiscalciuminfluxfacilitatestheprolongedcontractionofcardiacmusclefibers.Thecellthenmovesintorapidrepolarization.Repolarizationisbasicallyaregroupingphase,inwhichthecellmembranebecomespolarizedagainwithapositivechargeontheouterandanegati

4、vechargeontheinnersurfaceofthecellmembrane.Inthecaseofcardiacmyocytes,thesodiumandcalciumchannelscloseandsodiumandcalciumnolongermoveintothecell.Toreestablishthepolaritywithinthecell,thecellmembranebecomesmorepermeabletopotassium.Thispositivelychargedion(K)exitsthecell.Thisproce

5、ssisrepeatedagainandagaintoproducecardiaccontractionandrelaxationthatischaracteristicoftheheart.Pwavethedepolarizationoftheatriaviathesinoatrialnode•P-QintervalthedepolarizationoftheAVnodeandbundlefibers•QRSdepolarizationoftheventricles•Trepolarizationoftheventricles•Ure

6、polarizationofPurkinjefibersCardiacOutputMeasurementoftheheart’sefficiencytopumpoptimalamountsofbloodisreferredtoascardiacoutput.Cardiacoutput(CO)dependsonstrokevolume(SV)andheartrate(HR)andisexpressedas:CO=SVXHR.Strokevolumeistheamountofbloodpumpedoutofoneventricleoftheheartina

7、singlebeat.Heartrateisthenumberofheartbeatsthatoccurinoneminute.Cardiacoutputvarieswithage,bodysize,andmetabolicneedsofbodytissues.Theaveragecardiacoutputinadultsisabout3.5to8.0L/min.Thismeansthateveryminute,upto8Lofbloodmovesthroughtheheart.BloodPressureBloodpressureisthepressu

8、reortensionofthebloodwithinthesystemicarteries.