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首页 不同因素对家兔血压的影响

不同因素对家兔血压的影响.实验结果中英文分析

不同因素对家兔血压的影响

浅叹似水年华
2018-09-07 0人阅读 举报 0 0 0 暂无简介

简介:本文档为《不同因素对家兔血压的影响doc》,可适用于医药卫生领域

不同因素对家兔血压的影响实验原理动脉血压主要受心输出量和外周阻力的影响。动脉血压的高低是衡量心血管活动的重要指标。正常情况下,机体的动脉血压保持相对恒定。这种恒定是通过神经体液调节实现的。神经调节主要是心血管反射,其中最重要的是颈动脉窦和主动脉弓压力感受性反射。体液调节最主要的是儿茶酚胺类激素(如肾上腺素和去甲肾上腺素)。ArterialbloodpressureismainlyinfluencedbycardiacoutputandperipheralresistanceThediscretionofthearterialbloodpressureistheimportantindicatorsofcardiovasculareventsUndernormalcircumstances,thebody'sarterialbloodpressureremainedrelativelyconstantThisconstantisachievedbyneurohumoralregulationNeuromodulationmainlycardiovascularreflex,oneofthemostimportantisthecarotidsinusandaorticarchbaroreceptorreflexHumoralregulationisthemostimportantofcatecholaminehormone(eg,epinephrineandnorepinephrine)加入去甲肾上腺素后,观察到平均动脉压抬高,心率减慢。这是因为:去甲肾上腺素主要与α受体结合,也可与心肌β受体结合,但与血管平滑肌的β受体结合的能力较弱。通过α受体的激动,可引起血管极度收缩,使血压升高,冠状动脉血流增加通过β受体的激动,使心肌收缩加强,心排出量增加。总的来说其作用是使外周大多数血管收缩,外周阻力明显增大,动脉血压明显升高。同时,去甲肾上腺素可作用于心肌β受体而使心跳加快加强,但在整体内由于它使动脉血压明显升高,通过降压反射增强而引起心率减慢。use:norepinephrineMainandalphareceptors,canalsobecombinedwithmyocardialbetareceptor,buttheabilitytocombinethebetareceptorandvascularsmoothmuscleExcitedbyalphareceptors,cancausevascularcontraction,bloodpressure,coronarybloodflowincreasedExcitedbybetareceptors,toreinforcethemyocardialcontractionandcardiacoutputincreaseOverallitsroleistomakethemostperipheralvasoconstriction,peripheralresistanceincreasesobviously,arterialbloodpressureincreasedsignificantlyAtthesametime,canbeappliedtonorepinephrinemyocardialbetareceptorandmaketheheartbeatfastertostrengthen,butwithintheoverallbecauseitmakesthearterialbloodpressureincreasedsignificantly,causedbydepressorreflexslowheartbeat加入乙酰胆碱后,观察到心率变慢,平均动脉压下降。这是因为:外源乙酰胆碱作用于血管内皮细胞膜上的M受体,引起血管的舒张。Ach能使cAMP浓度降低,心率减慢,心房收缩力减弱,传导性减弱。心率变慢则流向外周的血量变多,舒张压更低。心房收缩力减弱则收缩压也有下降。平均动脉压降低。但是因为血回心时间变长,因此,回心血量较多,脉压增加。而大多数血管没有Ach受体,Ach对外周阻力影响不大。OnthevascularendothelialcellmembraneofMreceptor,causingvascularrelaxationAchcanlowertheconcentrationcAMP,theheartrateslows,atrialcontractionforceisabate,theconductivitydecreasedHeartrateslowmovingperipheralbloodmore,diastolicpressureislowerAtrialcontractionforcedecreasedsystolicbloodpressurehasdroppedMeanarterialpressuredecreasedButbecausebloodchangetime,therefore,thechangeofbloodismore,increasedpulsepressureWhilemostofthebloodvesselswithoutAchreceptors,Achforeignweeksimpactresistance夹闭一侧颈总动脉s后,观察到兔动脉血压升高的现象。夹闭颈动脉后,远心端的颈动脉窦张力感受器感受到血压下降,传出神经冲动的频率减慢。使心迷走紧张减弱,心交感和心缩血管紧张加强,作用于心脏,使心率加快,心输出量增加,血管收缩,血管外周阻力增加,从而血压恢复性升高。若血压下降过大,交感缩血管紧张还会扩展到静脉系统,是静脉收缩,促进血液回心,使每博输出量增加。clippedcarotidartery,thecarotidsinusontelecentrictensionsensorfeelbloodpressuredropped,thefrequencyoftheefferentnerveimpulsesslowdownMakeheartvagustensionabate,cardiacsympatheticandheartbloodvesselswastense,ACTSontheheart,heartrate,increasedcardiacoutput,vasoconstriction,bloodvesselsincreaseperipheralresistance,andelevatedbloodpressurerecoveryIfadropinbloodpressureistoolarge,thesympatheticvasculartensionwillalsoextendtothevenoussystem,istheveincontraction,promotebloodchange,tomakeeveryPooutputincrease牵拉一侧颈总动脉,血压下降,这是由于颈动脉张力感受器在松开动脉夹时感受到血压突然增大,传出神经冲动的频率增强,信息传到心血管中枢,使心迷走紧张增强,心迷走神经兴奋时,其末梢释放乙酰胆碱,乙酰胆碱与心肌细胞膜上的M受体结合,引起心脏负性的变时变力变传导作用及血管的舒张,血管外周阻力减小,从而血压降低。Pullonesideofcommoncarotidartery,dropinbloodpressure,backtonormalThisisduetothetensionofthecarotidarteryToloosenthearteryclampfeelbloodpressuresuddenlyincreases,theefferentnerveimpulsefrequencyincreases,theinformationtothecardiovascularcenter,heartvagustension,enhanceheartvagusnerveexcitement,itsperipheralreleaseacetylcholine,acetylcholineandmyocardialMreceptorsonthecellmembrane,causestheheartNegativetimevaryingforcetransmissionandthediastolicbloodvessels,vascularperipheralresistancereduced,therebyreducingbloodpressure刺激完整减压神经及其中枢端均可引起血压下降,而刺激该神经外周端基本不变。证明了兔减压神经是传入神经,其作用是将主动脉弓感受器发出的冲动传入延髓心血管中枢,反射性引起血压降低。因此,刺激完整的减压神经或其中枢端,使传入中枢的冲动增加,致血压明显下降,而刺激其外周端虽又冲动传向外周,但不会引起血压变化。Clearrabbitdepressornervedepressorafferentnerve,itseffectisaorticarchimpulsefromthereceptorintothemedullaoblongatacardiovascularcenter,reflectiveleadtolowerbloodpressureTherefore,stimulatethecompletedecompressionofnerveoritscentral,increasethecentreoftheimpulse,tosignificantlylowerbloodpressure,andstimulateZhouDuanisoutsideitsimpulsetoperipheral,butdoesnotcausethebloodpressurechanges刺激迷走神经和迷走神经外周端都能引起明显的减压反应,而刺激迷走中枢端则没有减压反应,只是血压稍有轻微抬升变化。证明迷走神经是传出神经。心迷走神兴奋时,其末梢释放乙酰胆碱,乙酰胆碱与心肌细胞膜上的M受体结合,引起心脏负性的变时变力变传导作用及血管的舒张。同时,迷走神经中含有从延髓下行的传出纤维,通向心脏。节前纤维末端释放Ach,节后纤维末端释放Ach,属于副交感神经纤维,能使cAMP浓度降低,心率减慢,心房收缩力减弱,传导性减弱。从而使心输出量变小,平均动脉压降低。此外,还有主动脉体化学感受器的上行纤维在迷走神经中并行,化学感受器受刺激的效应是血压升高。所以,刺激迷走中枢不能引起减压反应,却可以使血压轻微抬高。StimulatethevagusnerveandvagusnerveZhouDuancancauseobviousstressreaction,nostressreactionandstimulatethevaguscentralend,isonlyslightlyraisedbloodpressurechangesProvedvagalefferentnerveCardiacvagusgodwhenexcitedthemtoreleasetheacetylcholineendings,acetylcholineandmyocardialMreceptorsonthecellmembrane,causingheartnegativechangetimevaryingforceconductionofdiastolicfunctionandbloodvesselsAtthesametime,thevagusnervecontainsthemedullaoblongatadownwardefferentfibers,totheheartFirst,releasetheAchendofthefibreafterfiberendreleaseAch,belongtotheparasympatheticnervefiber,canlowertheconcentrationcAMP,theheartrateslows,atrialcontractionforceisabate,theconductivitydecreasedSothatthecardiacoutputquantityissmall,meanarterialpressuredecreasedInaddition,thereareaorticbodychemoreceptorupwardfibersinthevagusnerveinparallel,chemicalsensorsbystimulatingeffectisincreasedbloodpressureSo,stimulatethevaguscentralcannotcausestressreaction,canmakebloodpressureslightlyraised

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