呼吸英文班和7年制最后稿課件

MiaoBing(繆兵)InstituteofPhysiologyOffice:6330Tel:83902E-mail:miaobing@MiaoBing(繆兵)1呼吸英文班和7年制最后稿課件2AnOverviewofKeyStepsinRespirationAnOverviewofKeyStepsinRe3RespiratorySystemDivisionsUppertractnose,pharynxandassociatedstructuresLowertractlarynx,trachea,bronchi,lungsRespiratorySystemDivisionsUp4ConductingZoneAllstructuresairpassesthroughbeforereachingtherespiratoryzone.CartilagesthatkeeptubesystemopenandsmoothmusclesthatcontrolstubediameterWarmsandhumidifiesinspiredair.Filtersandcleans.Insertfig.16.5ConductingZoneAllstructures5RespiratoryZoneRegionsofgasexchangebetweenairandblood.Including:respiratorybronchiolesalveolarducts,sacsandalveoli.RespiratoryZoneRegionsofgas6AirwaybranchingAirwaybranching7BronchiolesandAlveoliBronchioles8RespirationistheprocessbywhichthebodytakesinandutilizesO2andgetsridofCO2.Respirationistheprocessby9RespirationcanbedividedintofourmajorfunctionaleventsPulmonaryventilation:movementofairintoandoutoflungs.Gasexchangebetweenairinlungsandblood.Transport

ofoxygenandcarbondioxideinblood.Internalrespiration:gasexchangebetweenbloodandtissues.Respirationcanbedividedint10FunctionsofRespiratorySystemGasExchange:Oxygenentersbloodandcarbondioxideleaves.RegulationofBloodpH:AlterspHbychangingbloodcarbondioxidelevels.*VoiceProduction:Vibrationofvocalcordsinducedbymovingairmakessoundsandspeeches.*SenseofSmell(Olfaction):Smelloccurswhenairbornesmell-inducingmoleculesmoveintonasalcavity.*Protection:Againstmicroorganismsbypreventingentryandremovingthem.FunctionsofRespiratorySyste11OutlineSectionI:PulmonaryVentilationSectionII:GasExchangeinLungsandTissues*SectionIII:TransportofO2andCO2inBlood.SectionIV:RegulationofRespirationOutlineSectionI:PulmonaryV12Section1:PulmonaryVentilationPulmonaryVentilation:theinflowandoutflowofairbetweentheatmosphereandthelungalveoli,whichisdeterminedbytheactivityoftheairways,thealveoliandthethoraciccage.Airmovesfromareaofhigherpressuretoareaoflowerpressure;Pressureisinverselyrelatedtovolume.Section1:PulmonaryVentilat13ImportantStructuresAssociatedwithPulmonaryVentilationImportantStructuresAssociate14AirwaysThepathwayforairflow:nose-alveoliToprotectthebody:ProtectionAgainstmicroorganismsbypreventingentryandremovingthemTowarmandhumidifytheinspiredairAirwaysThepathwayforairflo15Alveoli

Number:300millionsDiameter:0.25mmTotalarea:70m2TwogroupsofcellsI：smallalveolarcellsII：largealvoelarcells(DPPC).AlveoliNumber:300millions16RrespiratoryMembrane(RM)Themembraneousstructurethatgasmoleculesmustcrosswhengasexchangeoccursbetweenthealveoliandpulmonarycapillaries.(alsonamedalveolarmembrane,alveolar-capillarymembrane).RrespiratoryMembrane(RM)The17CompositionofRM1.Fluidandsurfactant；2.Epithelialcellsofalveoli3.Basementmembraneofalveoli4.cleft5.Basementmembraneofcapillary6.EndothelialcellsofcapillaryCompositionofRM18ThickenedRM:pulmonaryedema,fibrosisDecreasedareaofRM:fibrosis,emphysemaThickenedRM:pulmonaryedema,19SurfaceTensionandSurfaceActiveSubstance(Surfactant)SurfaceTensionandSurfaceAc20WhatisSurfaceTension?Withinfluid,allforcesbalanceAtsurfaceunbalancedforcesgeneratetensionWhatisSurfaceTension?Withi21SurfaceTensioninAlveoliExertedbyfluidinalveolitoresistdistension;Lungssecreteandabsorbfluid,leavingaverythinfilmoffluid.Thisfilmoffluidcausessurfacetension.H2Omoleculesatthesurfaceattractoneother.Directionofsurfacetension:towardthecenterofalveoli;Raisingpressureinalveoli.SurfaceTensioninAlveoliExer22SurfaceTensioninAlveoliLawofLaplace:Pressureinalveoliisdirectlyproportionaltosurfacetension;andinverselyproportionaltoradiusofalveoli.Pressureinsmalleralveoliwouldbegreaterthanthatinlargeralveoli,ifsurfacetensionwerethesameinboth.Insertfig.16.11SurfaceTensioninAlveoliLaw23CollapseExpandEffectofSurfaceTensiononAlveoliSizeAir

FlowCollapseExpandEffectofSurfac24SurfactantPreventsAlveolarCollapseSurfactantPreventsAlveolarC25WhatisSurfactant?surface-tension-decreasingsubstancesWhatisSurfactant?26SurfactantSurfactant27Examples：SecretionCells：typeIIalveolarcellsChemical：DPPCImportances:1.Enhancethecomplianceofthelungs2.Preventpulmonaryedema3.StabilizethealveoliExamples：28Thorax,PleuralCavityandIntrapleuralPressureThorax,PleuralCavityandInt29ThoraxThorax30ThoracicVolumeThoracicVolume31PleuraPleura32Pleuralcavity：theairtightandpotentialcavityformedbythevisceralandparietalpleura.ItisfilledwithpleuralfluidPleuralcavity：theairtighta33Pleuralfluid:producedbypleuralmembranesActsaslubricant;Helpsholdparietalandvisceralpleuralmembranestogether.pneumothoraxPleuralfluid:producedbyple34IntrapleuralPressureIntrapleuralPressure35Definition:thepressureinthepleuralcavity.Normalvalue:750mmHgTheendofinspiration；-5—-10mmHgTheendofexpiration：-3—-5mmHgThelowestandhighestvalue:-90mmHg----+110mmHgDefinition:thepressureinth36*Calculation:intrapleuralpressure=pressureofairinalveoli-contractingforceSourcesofcontractingforce:elasticforcesurfacetension*Calculation:37ImportancesofNegativeIntrapleuralPressureToholdthelungsandthoraxtogetherTopromotethepulmonaryandlymphaticcirculation.ImportancesofNegativeIntrap38ChangesinPleuralPressure,LungVolumeandAlveolarPressureChangesinPleuralPressure,L39PrinciplesofPulmonaryVentilationDrivingforces:pressuredifferencebetweenairinalveoliandatmosphereResistences:1)Elasticresistance〔70%〕2)Inelasticresistance:airwayresistance，pulmonarytissueresistance(viscosity,andinertia,30%totally〕PrinciplesofPulmonaryVentil40Definitionofinspiration:inspiratorymuscles---enlargedthorax---distendedlungs---decreasedpressureofairinalveoli---airflowintothelungs.Definitionofexpiration：omittedDefinitionofrespiratorymovement:thecycliccontractionanddistensionofthethoraxinducedbythemovementofrespiratorymuscles.Definitionofinspiration:ins41RespiratoryMusclesInspiratorymuscles:diaphragmandexternalintercostalExpiratorymuscles:abdominalrectiandinternalintercostalAssociatedmuscles:scalenus,sternocleidomastoidmuscleetc.RespiratoryMusclesInspiratory42MusclesofRespirationMusclesofRespiration43Occursbecausethethoraciccavitychangesitsvolume.Inspirationusesexternalintercostalsanddiaphragm.Expirationispassiveatrest,butusesinternalintercostalsandabdominalrectiduringsevererespiratoryload.Breathingrateis10-20breaths/minuteatrest,40-45atstrenuousexerciseinadults.BreathingOccursbecausethethoracicca44InspiratoryMovementTheprocessbywhichthethoraxisenlargedInspiratoryMovementTheproces45ExpiratoryMovementtheprocessbywhichthevolumeofthoraxisdecreasedExpiratoryMovement46SupplementsThoracicbreathingAbdominalbreathingEupnea:12-18breath/minForcedrespirationDyspneaArtificialrespirationSupplementsThoracicbreathing47IntrapulmonaryPressureThepressureofairinairwaysandalveolinormalrange:-1mmHg—+1mmHg1cmH2O=500mlIntrapulmonaryPressureThepre48ResistancestoVentilationElasticresistances:70%In-elasticresistances:30%airwayresistance(friction)viscousresistanceinertialresistanceResistancestoVentilationElas49ElasticResistanceDefinition:thecontractingforceofelastictissueinducedbybeinglengthened.Elasticity:Compliance:thereciprocaloftheelasticityofelastictissues(Inverselyrelatedtoelasticresistance).ElasticResistanceDefinition:50ComplianceoftheLungsDefinition:theratioofVofthelungsandPofthetranspulmonarypressureCalculation:CL=V/P(L/cmH2O)NormalValue:200ml/cmH2OComplianceoftheLungsDefinit51010050030LungVolume(%TLC)TranspulmonaryPressure(cmH2O)StaticLungComplianceC=DV/DPInflationDeflationNormalBreathing010050030LungTranspulmonaryPr521.CLcanbechangedmarkedlywithdifferentdistensionofthelungs.2.CL=theslopeatdifferentdots.3.Thehigherslope,thehigherCL,thesmallerelasticresistance.1.CLcanbechangedmarkedly53Elasticresistanceofthelungsisalwaysoneoftheresistancetoinspirationandthedrivingforcetoexpirationatthesametime.呼吸英文班和7年制最后稿課件54ElasticResistanceandComplianceofthoraxCT=V/P(L/cmH2O)Normal:200ml/cmH2OElasticResistanceandComplia55Calculationoftotalcompliance:1/Cs=1/CL+1/CT1/Cs=1/0.2+1/0.2Cs=0.1L/cmH2O.Calculationoftotalcomplianc56InelasticResistancesTheinelasticresistancescomprisestheairwayresistance(friction)andpulmonarytissueresistance(viscosity,andinertia).Airwayresistanceisbyfarthemoreimportantbothinhealthanddisease.Itaccountfor80%-90%oftheinelasticresistances.InelasticResistances57AirwayResistanceAirwayresistanceistheresistancetoflowofairintheairwaysandisduetofrictionalforce:1)intermolecularfrictionofgas2)frictionbetweengasmoleculesandthewallsoftheairways(tracheaandprimarybronchia).AirwayResistanceAirwayresist58SupplementsInverselyproportionaltothecross-sectionalareaSupplementsInverselyproporti59TypesofFlowTypesofFlow60LaminarFlowLaminarFlow:whenconcentriclayersofgasflowparalleltothewallofthetube,thevelocityprofileobeysPoiseuille’sLaw.LaminarFlowLaminarFlow:when61Poiseuille’sLawandResistanceAirwayRadiusorDiameteristheKEY.radiusby?resistanceby16-fold;-thinkbronchodilatorhere!!Poiseuille’sLawandResistanc62MajorsourcesoftheairwayresistancesNasalcavityandglottis:75%。Tracheaandlargebronchioles:15%Smallbronchioles:10%Majorsourcesoftheairwayre63Airway-resistance-increasingFactorsAnyfactorsthatdecreasesairwaydiameter,orincreasesturbulencewillincreaseairwayresistance,eg:RapidBreathing:becauseairvelocityandhenceturbulenceincreases;NarrowedAirways:asthma,parasympatheticstimulation,etc.Emphysema:whichdecreasessmallairwaydiameterduringforcedexpiration.Airway-resistance-increasingF64ControlofAirwaySmoothMuscleSmoothmusclesofbronchiiscontroledbysympathetic,parasymtheticnervesandchemicalsNeuralControl:Adrenergic?2-Receptors:dilatation;Parasympathetic-muscarinicreceptors:constriction;ControlofAirwaySmoothMuscl65ControlofAirwaySmoothMuscleLocalFactors:Histamine:H1receptors-constriction;Histamine:H2receptors-dilation;Slowreactivesubstanceofanaphylaxsis-constriction-allergicresponsetopollen;ProstaglandinsEseries-dilation;ProstaglandinsFseries-constriction.ControlofAirwaySmoothMuscl66ControlofAirwaySmoothMuscleEnvironmentalPollution:smoke,dust,sulfurdioxide,someacidicelementsinsmog;Elicitconstrictionofairwaysmediatedby:parasympatheticreflexlocalconstrictorresponsesControlofAirwaySmoothMuscl67Insomediseases,airwayresistancecanbechangedmarkedlyInsomediseases,airwayresis68PulmonaryVolumesandPulmonaryCapacitiesPulmonaryVolumesandPulmonar69PulmonaryVolumes1)TidalVolume(TV):Volumeofairinspiredorexpiredduringanormalquietinspirationorexpiration(400–500ml).Ralativelyconstant.2)InspiratoryReserveVolume(IRV):maximumextravolumeofairthatcanbeinspiredoverandabovethenormaltidalvolume(1500–2000ml).Decreasedinfibrosis,emphysemaetc.PulmonaryVolumes1)TidalVolu703)ExpiratoryReserveVolume(ERV):maximumextravolumeofairthatcanbeexpiredbyforcefulexpirationaftertheendofanormaltidalexpiration(900–1200ml).Decreasedinemphysemaetc.4)ResidualVolume(RV):Volumeofairremaininginrespiratorypassagesandlungsafterthemostforcefulexpiration(1500mlinmaleand1000mlinfemale).Increasedinemphysema;Decreasedinfibrosis.3)ExpiratoryReserveVolume(71PulmonaryCapacities1)InspiratoryCapacity(IC):theamountofairapersoncanbreathein,beginningatthenormalquietexpiratorylevelanddistendinglungstothemaximumamount.Tidalvolumeplusinspiratoryreservevolume.Decreasedinfibrosisandemphysema.PulmonaryCapacities1)Inspira722)FunctionalResidualCapacity(FRC):amountofairthatremainsinlungsattheendofnormalquietexpiration.Expiratoryreservevolumeplustheresidualvolume.Increasedinemphysema;Decreasedinfibrosis2)FunctionalResidualCapacit733)VitalCapacity(VC):maximumamountofairapersoncanexpelfromlungsafterfirstfillingthelungstotheirmaximumextentandthenexpiringtothemaximumextent.Sumofinspiratoryreservevolume,tidalvolume,andexpiratoryreservevolume.Decreasedinfibrosis,emphysema,COPD.3)VitalCapacity(VC):maximu744)TotalLungCapacity(TLC):maximumvolumetowhichthelungscanbeexpandedwiththegreatestpossibleeffort.Sumofinspiratoryandexpiratoryreservevolumesplusthetidalvolumeandresidualvolume.Decreasedinfibrosis,emphysema,COPD.4)TotalLungCapacity(TLC):755)ForcedVitalCapacity(FVC)Inspireasmuchairaspossiblefirst(tothemaximumextent),thenexpiretheinspiredairasforcefully,quicklyandmuchaspossible,themaximumvolumeofairthatcanbeexpiredmeansFVC(slightlysmallerthanvitalcapacity).Representtheairwayresistencesandcomplienceofthelungsbetter.

NormalValues:4L(decreaseswithaging).5)ForcedVitalCapacity(FVC)76SignificantlydecreasedFVCsuggestsdamagestolungparenchyma:Restrictivelungdisease(fibrosis)Obstructivelungdiseased(acuteasthma/COPD)Constructivelungdisease(emphysema)Lossoffunctionalalveoli(atelectasis)SignificantlydecreasedFVCsu776)ForcedExpiratoryVolume(FEV)Inspireasmuchairaspossiblefirst(tothemaximumextent),thenexpiretheinspiredairasforcefully,quickly

aspossible,themaximumvolumesofairthatcanbeexpiredwithin1s,2sand3smeansFEV1,FEV2,FEV3respectively.ShouldbenormalizedasratiosofFEV1/FVC,FEV2/FVC,FEV3/FVC.Representtheairwayresistenceandcomplienceofthelungsbest.6)ForcedExpiratoryVolume(F78NormalsforFEV1/FVC,FEV2/FVC,FEV3/FVC:FEV1/FVC=0.83;FEV2/FVC=0.96;FEV3/FVC=0.99.DecreasedratiosofFEV1/FVC,FEV2/FVCandFEV3/FVC(especiallyreducedFEV1/FVC)suggestsobstructivedamagestotheairways:Acuteobstruction:

Asthma(reversible),canbetreatedwithbronchodilators.Chronicobstruction:

Chronicobstructivepulmonarydisease(COPD,irreversible),cannotbetreatedwithbronchodilators.NormalsforFEV1/FVC,FEV2/FVC79ObstructiveLungDiseasesDiseaseswithreducedradiusoftheairwaysandmarkedlyincreasedairwayresistance(asthma/bronchitis)

Resistanceisinverselyrelatedtor4NormalAirwayAirwayofObstructiveDiseaseObstructiveLungDiseasesDisea80Volume(litres)Time(sec)DecreasedForcedExpiratoryVolumein1sec-FEV1,FVCandFEV1/FVC1secFEV1<80%ofFVCObstructiveLungDiseasesVolume(litres)Time(sec)Decre81呼吸英文班和7年制最后稿課件82RestrictiveLungDiseasesDiseasesthatreducetheeffectivesurfaceareaavailableforgasexchange(fibrosis)NormalLungVolumeDecreasedLungVolumeinRestrictiveDiseaseRestrictiveLungDiseasesDisea83Volume(litres)Time(sec)MarkedlyDecreasedTotalLungCapacity,VitalCapacity,FVC,FEV1andFEV1/FVCRestrictivelungdiseaseVolume(litres)Time(sec)Marke84呼吸英文班和7年制最后稿課件85MinuteVentilationVolumeandAlveolarVentilationvolumeMinuteventilationvolume:Totalamountofairmovedintoandoutofrespiratorysystemperminute(TV×RT,6000-9000ml).Minutemaximalrespiratoryvolume:

Inspireairasforcefully,quickly

aspossible,themaximumvolumesofairthatcanbeinspiredintothelungseachminute(70-120L/min).MinuteVentilationVolumeand86Respiratoryrate(RR):timesofbreathsperminute.Deadspace(DS):Partofrespiratorysystemwheregasexchangedoesnottakeplace.Minutealveolarventilationvolume:totalvolumeoffreshairenteringthealveoliandadjacentgasexchangeareaseachminute.(TV－DS)RR.Respiratoryrate(RR):timeso87DeadSpaceDefinition:Areawheregasexchangecannotoccur.IncludesmostofairwayvolumeAnatomicaldeadspace(=150ml)AirwaysAlveolardeadspace(=0)Physiologicaldeadspace=anatomical+alveolardeadspaceDeadSpaceDefinition:Areawhe88RRTVDSMVVAVV(times/min)(ml)(ml)(ml)(ml)165001508000560081000150800068003225015080003200呼吸英文班和7年制最后稿課件89Section2RespiratoryGasesExchangeSection290PhysicalPrinciplesofGasExchangePhysicalPrinciplesofGasExc91PartialpressureofgasesThepressureexertedbyeachtypeofgasinamixture.DiffusionofgasesthroughliquidsConcentrationofagasinaliquidisdeterminedbyitspartialpressureanditssolubilitycoefficient.Partialpressureofgases92PartialPressuresofGasesBasicCompositionofAir79%Nitrogen21%OxygenInamixtureofgases,eachgasexertsapartialpressureproportionaltoitsmolefraction.TotalPressure=sumofthepartialpressuresPgas=Pb×FgasPN2=760×0.79=600.4mmHgP02=760×0.21=159.6mmHgTotalPressure(atsealevel)Pbarometric=760mmHgPb760mm

HgPbPartialPressuresofGasesBasi93ConsideracontaineroffluidinavacuumPartialPressureofGasesinFluidsEachgashasaspecificsolubility

O2SolubilityCoefficient=0.003ml/100mlBlood C02=0.06ml/100mlBlood(×20of02)Gasesdissolveinfluidsbymovingdownapartialpressuregradientratherthanaconcentrationgradient.WhenitisopenedtotheairMoleculesofgasesbeginto

enterthefluid.Consideracontaineroffluid94PartialPressureofGasesinFluidsAfterashorttime,

thenumberofmoleculesthenumberofmolecules

ENTERING = LEAVING

Atequilibrium,ifthegasphasehasaPO2=100mmHg, theliquidphasealsohasaPO2=100mmHgPartialPressureofGasesinF95Themechanismofgasexchangebetweenthealveoliandpulmonarycapillariesandeventuallyfromthecapillariestothetissues------Diffusion;Gasesdiffusefromareaofconc.(pp)toconc.(pp);

Diffusiondependsonperfusionandthepartialpressure(pp)exertedbyeachgas;Themechanismofgasexchange96GasExchangeintheLungsandtheTissuesGasExchangeintheLungsand97PO2andPCO2inBloodPO2andPCO2inBlood98O2andCO2DiffusionGradientsOxygenThelungs:Movesfromalveoliintoblood.Bloodisalmostcompletelysaturatedwithoxygenwhenitleavesthecapillary.Thetissues:Oxygenmovesfromtissuecapillariesintothetissues.CarbonDioxideThetissues:Movesfromtissuesintotissuecapillaries;Thelungs:Movesfrompulmonarycapillariesintothealveoli.O2andCO2DiffusionGradients99Factorsthataffectgasexchange〔1〕Pressuredifference〔P〕〔2〕Molecularweight〔MW〕〔3〕Solubility〔S〕；〔4〕Area〔A〕〔5〕Distance〔d〕〔6〕Temperature〔T)Factorsthataffectgasexchan100

PATSDiffussion=d

MW

101Ventilation/perfusionratio(VA/Q;V/Q)Theratioofalveolarventilationperminute〔VA〕andalveolarbloodflowperminute〔Q〕.Ventilation/perfusionratio(V102Bothofventilationandperfusionarebetteratthebaseofthelungsthanthatattheapex,butthechangesinbloodflowaremoresteepthanthatinventilation.Therefore,V/Qratiorisessharplyfromthebasetotheapex.Normal:0.84Bothofventilationandperfus103Pulmonarydiffusioncapacity(DL):Thevolumeofagasthatcrosstherespiratorymembraneandentersthebloodperminutedrivenbythepressuredifferenceof1mmHg.DL=V/(PA-PC)V:ml/minPA:partialpressureinalveoli.PC:partialpressureinpulmonarycapillariesNormal：DL(O2):20ml/min/Kpa;DL(CO2):400ml/min/Kpa.Pulmonarydiffusioncapacity(104FactorsAffectingGasDiffusioninLungsFactorsAffectingGasDiffusio105PropertiesoftheGasMolecularWeight.Diffusionrateisinverselyproportionaltothesquarerootofthemolecularweight;Temperature------kineticmotionofmolecules;Solubilitycoefficientinwater.

Eachgashasaspecificsolubility:

O2solubilitycoefficient=0.003ml02/100mlblood; CO2=0.06ml/100mlblood(×20ofO2)PropertiesoftheGas1062.PartialPressureoftheGasesAlveoliVentilation;BloodPerfusioninLungCapillary;SpeedoftheChemicalReaction.slowchemicalreactionHCO3-+H+-----H2CO3---H2O+CO2reducestheexchangeofCO2inthelungs.So,duringthegasexchangeinexternalrespiration,theexchangeofCO2isalittlelowerthanthatofO2.2.PartialPressureoftheGas1073.

PropertiesoftheLungAreaoftheRespiratoryMembrane(Definition:

themembranousstructurethatgasesmustcrossduringgasexchange,sixlayers).DistanceoftheDiffusion(thicknessofRM);ViscosityoftheMedium(fluid).3.PropertiesoftheLung108InternalRespirationAllcellsrequireO2formetabolism;AllcellsrequiremeanstoremoveformedCO2;Gasexchangesalsooccuratcellularlevel.InternalRespirationAllcells109ConceptofInternalRespiration:Gasexchangesbetweenthecapillaryandthetissuesthroughoutthebody.Mechanism:SimpleDiffusion.FactorsAffectingInternalRespiration:Distancebetweencellsandcapillary;MetabolicRate;SpeedoftheBloodFlowinCapillary.ConceptofInternalRespiratio110Section3GasTransportinBloodSection3111TwoFormsofExistenceofGasesinBlood:physicallydissolvedandchemicallycombinedgases.MostofO2andCO2inbloodistransportedinthemannerofchemicalcombination.Onlythegasesinphysicaldissolutioncontributetopartialpressure(PP)anddiffusetoaplacewithlowPP.Equilibriumbetweenthetwoforms:PhysicalDissolution

ChemicalCombinationPPPPBasicMechanismofGasTransportationTwoFormsofExistenceofGase112O2TransportMethod

PercentageDissolvedinPlasma1.5%CombinedwithHemoglobin98.5%O2TransportMethod113ChemicalStructureofHemoglobinAproteinwith4subunits,eachofwhichcontainsahememoietyattachedtoapolypeptidechain.ChemicalStructureofHemoglob114FormationofOxyhemoglobinOxyhemoglobinisformedwhenO2moleculereversiblyattachestothehemeportionofHb.ThehemeunitcontainsFe+2whichprovidestheattractiveforce.Theprocessissummarizedasfollows:O2+HbHbO2FormationofOxyhemoglobinOxyh115Innormaladults,mostoftheHbcontains2αand2βchains.Eachofthe4ironatomscanbindreversiblyoneO2molecule.Theironstaysintheferrousstate,sothatthereactionisanoxygenation,notanoxidation.WhensaturatedwithO2(4O2inoneHb),itisalwayswrittenasHb4O8.Thisreactionisrapid(lessthan0.01s).deoxygenation(reduction)ofHb4O8isalsoveryrapid.Innormaladults,mostofthe116OxygenCapacity:MaximumquantityofO2thatwillcombinechemicallywiththeHbinaunitvolumeofblood.NormalValue:20mlofO2%.OxygenContent:

Realamountof

O2inblood.OxygenSaturation:TheratioofO2contenttoO2capacity.BasicConceptsOxygenCapacity:Maximumquant117O2-HbDissociationCurvethecurveshowingtherelationofpercentO2saturationortheO2-carryingpowerofHbtoPO2

O2-HbDissociationCurvethecu118ThreePortionsofO2-Hb

DissociationCurveA.Flattenedupperportion:(thealveoli)B.Steepmiddleportion(thetissue)C.Lowerportion(hypoxiccondition)ThreePortionsofO2-HbDissoc119FactorsthatShifttheO2-Hb

DissociationCurveFactorsthatShifttheO2-HbD120pHandPCO2:BohrEffect-------increasedO2releaseinthetissuepHandPCO2:BohrEffect121

TemperatureThehigherT,themorereleasedoxygen;thelowerT,thelessreleasedoxygenTemperature1222,3-diphosphoglycerate(2,3,-DPG)Abyproductofanaerobicglycolysis.Presentinespeciallyhighconcentrationinredbloodcells(highlevelof2,3-DPGmutase).TheaffinityofhemoglobinforO2diminishesastheconcentrationof2,3-DPGincreaseintheredbloodcells.Themore2,3-DPG,themorereleasedO2intissues.2,3-diphosphoglycerate(2,3,-1234)CarbonMonoxide(CO)COcombinesHbatthesamepointasO2does,andcandisplaceO2fromHb.CObindswithHbabout250timesasmuchtenacityasO2.Therefore,PCOonlyalittlegreaterthan0.4mmHgcanbelethal.4)CarbonMonoxide(CO)124CO2Transport

Method

PercentageDissolvedinplasma7-10%ChemicallyboundtoHbinRBCs20-30%AsHCO3-inplasma60-70%CO2TransportMethod125CarbaminohemoglobinFormationCO2moleculereversiblyattachestoanaminoportionofHb.CO2+HbHbCO2CarbaminohemoglobinFormationC126FormationofHCO3-ThecarbonicanhydrasestimulatesH2OwatertocombinequicklywithCO2CO2+H20H2CO3FormationofHCO3-Thecarbonic127HCO3-FormationH2CO3breaksdowntoreleaseaH+andHCO3-H2CO3H++HCO-3HCO3-FormationH2CO3breaksdo128CO2TransportandCl-MovementCO2TransportandCl-Movement129Section4RegulationofRespirationSection4130RespiratoryCentersandFormationoftheRespiratoryRhythm1,RespiratoryCentersRespiratoryCentersandFormat131BrainstemTransectionNormalPatternGaspingPatternsApneusticBreathingRespiratoryArrestIncreasedInspiratoryDepthBrainstemTransectionNormalGa132SpinalCordMoto