基础医学各论Ⅰ：11-循环系统生理4

CardiovascularPhysiologyRegulationofCardiovascularActivitiesLectureOutlineNervousRegulationHumoralRegulationAutoregulationNervousRegulationInnervationofcardiovascularsystemNervousregulationofthecirculationCardiacmechanismsofnorepinephrineMechanismsofnorepinephrine—increaseNa+&Ca2+permeabilityIf,phase4spontaneousdepolarization,autorhythmicity

Ca2+influx

,phase0amplitude&velocity

,conductivity

Ca2+influx,Ca2+release,[Ca2+]i,contractility

AsymmetricalinnervationofsympatheticnerveCardiacmechanismsofacetylcholineMechanismsofacetylcholine—increaseK+&decreaseCa2+permeabilityK+outward

,|MRP|

,phase4spontaneousdepolarization

,autorhythmicity

InhibitionofCa2+channel,phase0amplitude&velocity

,conductivity

Ca2+influx,[Ca2+]i,contractilityCardiaceffectofparasympatheticstimulationInteractionofsympatheticandparasympatheticnervesPredominanceofautonomicnervesCardiovascularCenterAcollectionoffunctionallysimilarneuronsthathelptoregulateHR,SV,andbloodvesseltoneVasomotorcenterLocatedbilaterallymainlyinthereticularsubstanceofthemedullaandofthelowerthirdoftheponsVasoconstrictorareaVasodilatorareaCardioinhibitorarea–dorsalnucleiofthevagusnervesandambiguousnucleus

Sensoryarea–tractussolitariusVasomotorcenterReticularsubstanceoftheponsMesencephalonDiencephalonHypothalamusCerebralcortexCerebellumHighercardiovascularcentersBaroreceptorReflexesArterialbaroreceptorsCarotidsinusreceptorAorticarchreceptorAfferentnerves(Buffernerves)Cardiovascularcenter:medullaEfferentnerves:cardiacsympatheticnerve,sympatheticconstrictornerve,vagusnerveEffector:heart&bloodvesselsBaroreceptorneuronsfunctionassensorsinthehomeostaticmaintenanceofMAPbyconstantlymonitoringpressureintheaorticarchandcarotidsinuses.Characteristicsofbaroreceptors:SensitivetostretchingofthevesselwallsProportionalfiringratetoincreasedstretchingRespondingtopressuresrangingfrom60-180mmHgReceptorswithintheaorticarcharelesssensitivethanthecarotidsinusreceptorsTheactionpotentialfrequencyinbaroreceptorneuronsisrepresentedhereasbeingdirectlyproportionaltoMAP.BaroreceptorneuronsdeliverMAPinformationtothemedullaoblongata’scardiovascularcontrolcenter(CVCC);theCVCCdeterminesautonomicoutputtotheheart.i.e.,MAPisabovehomeostaticsetpoint

i.e.,reducecardiacoutputReflexpathwayClickheretoplaytheBaroreceptorReflexControlofBloodPressureFlashAnimationTypicalcarotidsinusreflexMaintainingrelativelyconstantarterialpressure,reducingthevariationinarterialpressurePhysiologicalSignificanceOtherCardiovascularReflexesClickheretoplaytheChemoreceptorReflexControlofBloodPressureFlashAnimationHumoralRegulationVasoconstrictoragentsVasodilatoragentsRenin-angiotensinsystemJuxtaglomerularcellReninConstrictsresistancevesselsActsupontheadrenalcortextoreleasealdosteroneStimulatesthereleaseofvasopressinFacilitatesnorepinephrinereleasefromsympatheticnerveendingsStimulatesthirstcenterswithinthebrain

PhysiologicaleffectsofangiotensinIIEpinephrine&NorepinephrineSources Epinephrine---- adrenalmedulla Norepinephrine---- adrenalmedulla sympatheticnervesCatecholaminesNorepinephrineEpinephrine

Effects Epinephrine NorepinephrineReceptor a-adrenoceptor +++++

b-adrenoceptor ++ +Heart heartrate ++(invitro)

－(invivo) cardiacoutput +++ ±Vessels constriction(skin,visceral)++++ relaxation(SM,liver)－+++ totalperipheralresistance±+++Bloodpressure systolic ++++++ diastolic ±++ MAP +++Clinicalapplication positiveinotropicpressoragent agentA23-year-oldwomanpresentstoyouremergencyservicewithananaphylacticreactionafterbeingstungbyseveralbees.Shecomplainsofwheezingandshortnessofbreath.Onexamination,theclientisinacutedistress.BPis98/56mmHg,PR110/min,RR28/min,andtemperature98.7°F.Sheisimmediatelytreatedwithsupplementaloxygen.Intreatingthisconditionfurther,whatdrugisrequiredmosturgently?ATheophyllineBGlucagonCCimetidineDMethylprednisoloneEEpinephrineVasopressin(antidiuretichormone,ADH)

Endothelium-derivedvasoactivesubstancesVasodilatorfactors

PGI2--prostacyclinEDRF,NO--endothelium-derivedrelaxingfactor,nitricoxide

EDHF--endothelium-dependenthyperpolarizingfactorVasoconstrictorfactors

EndothelinAtrialnatriureticpeptide(ANP)ProducesnatriuresisanddiuresisDecreasesreninreleaseReducesto