生理學雙語課件呼吸1

respiration第五章呼吸生理1respiration第五章呼吸生理1221.外呼吸

肺通氣（外界空氣與肺泡之間的氣體交換過程）肺換氣(肺泡與肺毛細血管之間的氣體交換過程）呼吸的三個基本環(huán)節(jié)31.外呼吸呼吸的三個基本環(huán)節(jié)3氣體在血液中的運輸3.內(nèi)（組織）呼吸血液與組織、細胞之間的氣體交換過程4氣體在血液中的運輸4肺通氣和肺換氣5肺通氣和肺換氣5Thegoalsofrespirationaretoprovideoxygentothetissuesandtoremovecarbondioxide.Toachievethesegoals,respirationcanbedividedintofourmajorfunctionalevents:6Thegoalsofrespirationaretpulmonaryventilation,whichmeanstheinflowandoutflowofairbetweentheatmosphereandthelungalveoli;(2)diffusionofoxygenandcarbondioxidebetweenthealveoliandtheblood;7pulmonaryventilation,whichm(3)transportofoxygenandcarbondioxideinthebloodandbodyfluidstoandfromthecells;and(4)regulationofventilationandotherfacetsofrespiration.Thischapterisadiscussionofpulmonaryventilation.8(3)transportofoxygenandca第一節(jié)肺通氣9第一節(jié)肺通氣9一、實現(xiàn)肺通氣的結構特點及功能鼻、咽、喉、氣管直到終末細支氣管{上呼吸道{下呼吸道10一、實現(xiàn)肺通氣的結構特點及功能鼻、咽、喉、氣管直到終末111112121313二、肺通氣原理14二、肺通氣原理14（一）肺通氣的動力直接動力：肺泡與大氣之間的壓力差

原動力:呼吸運動呼吸肌收縮、舒張所造成的胸廓的擴大和縮小，稱為呼吸運動。15（一）肺通氣的動力151．呼吸運動（1）吸氣運動：膈肌收縮時中部下移，增大了胸腔的上下徑，肺容積隨之增大，產(chǎn)生吸氣。

平靜呼吸時膈肌收縮造成的通氣量占總通氣量的4/5。161．呼吸運動161717當肋間外肌收縮時，增大了胸腔的前后徑和左右徑，肺容積隨之增大,產(chǎn)生吸氣。18當肋間外肌收縮時，增大了胸1819192020（2）呼氣運動：平靜呼氣時，因膈肌和肋間外肌舒張，肺依靠本身的回縮力量而回位，產(chǎn)生呼氣。21（2）呼氣運動：21

用力呼吸：除上述肌肉外，有更多的吸氣肌與呼氣肌參與呼吸運動。22用力呼吸：22用力呼吸{吸氣（主動）膈肌和肋間外肌收縮，胸鎖乳突肌、斜角肌也收縮呼氣（主動）膈肌和肋間外肌舒張，腹壁肌肉、肋間內(nèi)肌收縮

平靜呼吸{吸氣（主動）膈肌和肋間外肌收縮

呼氣（被動）膈肌和肋間外肌舒張23用力呼吸{吸氣（主動）膈肌和肋間外肌收縮，胸鎖乳突肌、斜呼吸運動{腹式呼吸胸式呼吸膈肌舒縮引起的呼吸運動伴以腹壁的起伏，所以稱為腹式呼吸（abdominalbreathing）。24呼吸運動{腹式呼吸胸式呼吸膈肌舒縮引起的呼吸運動伴以腹由肋間肌舒縮使肋骨和胸骨運動所產(chǎn)生的呼吸運動，稱為胸式呼吸。Thoracicbreathing25由肋間肌舒縮使肋骨和胸骨運251.MechanicsOfPulmonaryVentilation627.4-628.3A.MusclesThatCauseLungExpansionandContraction629.2-630.2261.MechanicsOfPulmonaryVentThelungscanbeexpandedandcontractedintwoways:bydownwardandupwardmovementofthediaphragmtolengthenorshortenthechestcavityandbyelevationanddepressionoftheribstoincreaseanddecreasetheantero-posteriordiameterofthechestcavity.27ThelungscanbeexpandedandNormalquietbreathingisaccomplishedalmostentirelybythefirstofthetwomethods,thatis,bymovementofthediaphragm.Duringinspiration,contractionofthediaphragmpullsthelowersurfacesofthelungsdownward.28NormalquietbreathingisaccoThen,duringexpiration,thediaphragmsimplyrelaxes,andtheelasticrecoilofthelungs,chestwall,andabdominalstructurescompressesthelungs.29Then,duringexpiration,thedDuringheavybreathing,however,extraforceisachievedmainlybycontractionoftheabdominalmuscles,whichpushestheabdominalcontentsupwardagainstthebottomofthediaphragm.30Duringheavybreathing,howeveThesecondmethodforexpandingthelungsistoraisetheribcage.whentheribcageiselevated,makingtheantero-posteriorthicknessofthechestabout20percentgreaterduringmaximuminspirationthanduringexpiration.31ThesecondmethodforexpandinTherefore,allthemusclesthatelevatethechestcageareclassifiedasmusclesofinspiration,andthemusclesthatdepressthechestcageareclassifiedasmusclesofexpiration.Themostimportantmusclesthatraisetheribcagearetheexternalintercostals.32Therefore,allthemusclesthaThemusclesthatpulltheribcagedownwardduringexpirationare(1)theabdominalrecti,whichhavethepowerfuleffectofpullingdownwardonthelowerribsatthesametimethattheyandtheotherabdominalmusclescompresstheabdominalcontentsupwardtowardthediaphragm,and(2)theinternalintercostals.33ThemusclesthatpulltheribAstheexternalintercostalstheycontract,theypullribsforward,andthiscausesleverageontheribstoraisethemupward,therebycausinginspiration.Theinternalintercostalsfunctionexactlyoppositely,functioningasexpiratorymuscles,becausetheyanglebetweentheribsintheoppositedirectionandcauseoppositeleverage.34Astheexternalintercostalst2．肺內(nèi)壓肺內(nèi)壓是指肺泡內(nèi)的壓力。吸氣初，肺內(nèi)壓低于大氣壓，空氣進入肺泡。呼氣初，肺內(nèi)壓高于大氣壓，肺內(nèi)氣體流出。吸氣末和呼氣末，肺內(nèi)壓和大氣壓相等。352．肺內(nèi)壓35Alveolarpressureisthepressureoftheairinsidethelungalveoli.Whentheglottis聲門isopenandnoairisflowingintooroutofthelungs,thepressuresinallpartsoftherespiratorytree,allthewaytothealveoli,areequaltoatmosphericpressure,whichisconsideredtobethezeroreferencepressureintheairways–thatis,0centimeterswaterpressure.36AlveolarpressureisthepressTocauseinwardflowofairintothealveoliduringinspiration,thepressureinthealveolimustfalltoavalueslightlybelowatmosphericpressure(below0).37TocauseinwardflowofairiDuringnormalinspiration,alveolarpressuredecreasestoabout-1centimeterofwater.Thisslightnegativepressureisenoughtopull0.5literofairintothelungsinthe2secondsrequiredfornormalquietinspiration.38Duringnormalinspiration,alvDuringexpiration,oppositechangesoccur:Thealveolarpressurerisestoabout+1centimeterofwater,andthisforcesthe0.5literofinspiredairoutofthelungsduringthe2to3secondsofexpiration.39Duringexpiration,oppositech3.胸內(nèi)壓胸膜腔內(nèi)的壓力稱為胸內(nèi)壓。403.胸內(nèi)壓胸膜腔內(nèi)的壓力稱為胸內(nèi)壓。404141胸膜腔內(nèi)壓比大氣壓低，為負壓。平靜呼氣末胸膜腔內(nèi)壓約為-5—-3mmHg，吸氣末約為-10—-5mmHg。42胸膜腔內(nèi)壓比大氣壓低，為負壓。42胸內(nèi)壓=大氣壓-肺回縮力43胸內(nèi)壓=大氣壓-肺回縮力43胸內(nèi)壓=肺內(nèi)壓-肺彈性回縮力=大氣壓-肺彈性回縮力若以1個大氣壓為0，則胸膜腔內(nèi)壓=－肺彈性回縮力44胸內(nèi)壓=肺內(nèi)壓-肺彈性回縮力444545Pleuralpressureisthepressureofthefluidinthenarrowspacebetweenthelungpleuraandthechestwallpleura.46PleuralpressureisthepressuPleuralpressureisnormallyaslightlynegativepressure.Thenormalpleuralpressureatthebeginningofinspirationisabout-5centimetersofwater,whichistheamountofsuctionthatisrequiredtoholdthelungsopentotheirrestinglevel.47PleuralpressureisnormallyaThen,duringnormalinspiration,theexpansionofthechestcagepullsoutwardonthelungswithstillgreaterforceandcreatesastillmorenegativepressuretoanaverageofabout-7.5centimetersofwater.48Then,duringnormalinspiratio（二）肺通氣的阻力{彈性阻力（70%）非彈性阻力（30%）49（二）肺通氣的阻力{彈性阻力（70%）非彈性阻力（30%）41、彈性阻力和順應性（1）彈性阻力彈性組織在外力作用下變形時，有對抗變形和彈性回位的傾向，為彈性阻力。501、彈性阻力和順應性（1）彈性阻力50（2）順應性(compliance)順應性是指在外力作用下彈性組織的可擴張性。容易擴張者，順應性大，彈性阻力小；反之則相反。

51（2）順應性(compliance)順應性是指在外力作用下彈可見順應性（C）與彈性阻力（R）成反變關系：

C=1/R52可見順應性（C）與彈性阻52順應性用單位壓力變化（△P）所引起的容積變化（△V）來表示，單位是L/cmH2O，即C=△V/△PL/cmH2O。53順應性用單位壓力變化（△P）53Complianceintherespiratorysystem631.2-633.1describesthedistensibilityofthelungsandchestwall.isinverselyrelatedtoelastance,whichdependsontheamountofelastictissue.isthechangeinvolumeforagivenchangeinpressure.54Complianceintherespiratory?肺的彈性阻力{肺表面張力（2/3）肺組織彈性（1/3）(3)肺的彈性阻力的來源55?肺的彈性阻力{肺表面張力（2/3）肺組織彈性（1/3）(肺組織的彈性主要來肺組織的彈性纖維和膠原纖維。56肺組織的彈性主要來肺組織的彈性纖維和膠原纖維。56Resistencetopulmonaryventilation

633.2-634.4Resistantforcesofthelungs.Thesecanbedividedintotwoparts:(1)theelasticforcesofthelungtissueitself57ResistencetopulmonaryventilTheelasticforcesofthelungtissuearedeterminedmainlybytheelastinandcollagenfibersinterwovenamongthelungparenchyma.(2)theelasticforcescausedbysurfacetensionofthefluidthatlinestheinsidewallsofthealveoliandotherlungairspaces.58TheelasticforcesofthelungNatureofLungElasticRecoilTheelasticrecoilofthelungconsistsoftwokindsof

forces－tissueforcesandsurfacetensionforces.The

elasticityoflungtissueisdueprincipallytoelastin彈性蛋白fibers

inalveolarwallsandsurroundingsmallairways.

59NatureofLungElasticRecoil5?肺泡表面張力肺泡內(nèi)壁有一薄層液體，它與肺泡內(nèi)氣體形成了液-氣交界面，這里存在減小液-氣界面的力，使肺泡趨于縮小，稱為肺泡表面張力。60?肺泡表面張力肺泡內(nèi)壁有一薄層液體，它與肺泡60?肺泡表面活性物質是由肺泡Ⅱ型細胞分泌的一種復雜的脂蛋白，主要成分為二棕櫚酰卵磷脂。其主要作用是降低表面張力。61?肺泡表面活性物質是由肺泡Ⅱ型細胞分泌的一種復61Laplace定律：P=2T/rp肺泡內(nèi)壓T表面張力r肺泡半徑由于小肺泡表面活性物質的密度大，大肺泡表面活性物質分子的稀疏，則大小肺泡內(nèi)壓力相等，大小肺泡的穩(wěn)定性。62Laplace定律：P=2T/rp肺泡內(nèi)壓62?肺泡表面活性物質的作用降低表面張力{維持大小肺泡的容積相對穩(wěn)定調節(jié)肺泡的回縮力，有利呼吸使肺泡表面相對干燥，避免肺水腫63?肺泡表面活性物質的作用降低表面張力{維持大小肺泡的容Thesurfacetensionaccountsforabouttwothirdsofthetotalelasticforcesinthenormallungs.Thesurfacetensionelasticforcesofthelungsalsoincreasetremendouslywhenthesubstancecalledsurfactantisnotpresentinthealveolarfluid.64ThesurfacetensionaccountsfSurfactantisasurfaceactiveagent,whichmeansthatitgreatlyreducesthesurfacetensionofthewater.Itissecretedbyspecialsurfactant-secretingepithelialcellsthatconstituteabout10percentofthesurfaceareaofthealveoli.ThesecellsarearecalledtypeIIalveolarepithelialcells.65SurfactantisasurfaceactiveSurfactantisacomplexmixtureofseveralphospho-lipids,proteins,andions.Surfactant

consistsprimarilyofthephospholipid,(DPPC)whichisresponsibleforreducingthesurfacetension.66SurfactantisacomplexmixturAbnormalitiesofLungElasticRecoilLungelasticrecoilisincreasedbyreducedsurfactantactivityresultingfromdecreasedsynthesisorinactivation.Thebest-knownclinicaldisorderassociatedwithdecreasedsurfactantsynthesisistherespiratorydistresssyndromeofthenewborn.67AbnormalitiesofLungElasticSurfactantproductionmayalsobeimpairedfollowingtheinterruptionofpulmonaryperfusion,asinpulmonarythromboembolism血栓栓塞.Hydrostaticpulmonaryedemaandadultrespiratorydistresssyndromeare

associatedwithsurfactantinactivationduetoalveolar

flooding.

68SurfactantproductionmayalsoTheconsequencesofdecreasedsurfactantactivityincludedecreasedlungcomplianceduetoincreasedsurfacetensionandalveolarcollapse(atelectasis肺萎陷),decreasedlungvolumes(TLC,totallungcapacity,RV

residualvolume,andFRC

functionalresidualcapacity),andincreased

elasticworkofbreathing.69TheconsequencesofdecreasedThedecreasedlungcomplianceofinterstitialorinfiltrative浸潤性的lungdiseasesresultsfromtwomechanisms－decreaseddistensibilityand"lungshrinkage"70ThedecreasedlungcompliancePathologicallythesediseasesarecharacterizedbyalveolar

fillingwithinflammatoryexudate滲出物and/orreplacementof

alveolibyfibrosis,andthislossofalveolarunitsorlungshrinkagedecreasescompliance(seeabove).

71PathologicallythesediseasesInaddition,thesedisordersmayaltertheconnectivetissueelementsofthelung.resultinginincreasedlungelasticrecoil.Asaresult,TLC,RV,andfunctionalresidualcapacityaredecreased,andtheelasticwork

ofbreathingisincreasedinthesedisorders.72Inaddition,thesedisordersm2、非彈性阻力包括:

慣性阻力粘滯阻力

氣道阻力732、非彈性阻力73慣性阻力是氣流在發(fā)動、變速、換向時因氣流和組織的慣性所產(chǎn)生的。平靜呼吸時，慣性阻力小，可忽略不計。74慣性阻力是氣流在發(fā)動、變速、74粘滯阻力來自呼吸時組織相對位移所發(fā)生的磨擦。75粘滯阻力來自呼吸時組織相75氣道阻力來自氣體分子間和氣體分子與氣道之間的磨擦，是非彈性阻力的主要成分，約占80%-90%。76氣道阻力來自氣體分子間和氣體76R與1/r4成正比影響r的因素：

1、氣道管壁平滑肌的神經(jīng)調節(jié)2、化學因素的影響77R與1/r4成正比影響r的因素：1、氣道管壁平滑肌的神經(jīng)調（三）呼吸功78（三）呼吸功78三、基本肺容積和肺容量（一）基本肺容積（pulmonaryvolume)1．潮氣量每次呼吸時吸入或呼出的氣量為潮氣量（tidalvolume）。平靜呼吸時，潮氣量為500ml。運動時增大。79三、基本肺容積和肺容量（一）基本肺容積（pulmonary2．補吸氣量平靜吸氣末，再盡力吸氣所能吸入的氣量為補吸氣量（inspiratoryreservevolume），正常為1500-2000ml。802．補吸氣量803．補呼氣量平靜呼氣末，再盡力呼氣所能呼出的氣量為補呼氣量（expiratoryreservevolume），正常為900-1200ml。813．補呼氣量814．余氣量最大呼氣末尚存留于肺中不能再呼出的氣量為余氣量（residualvolume）。正常為1000-1500ml。824．余氣量82（二）肺容量（pulmonarycapacities）是基本肺容積中兩項或兩項以上的聯(lián)合氣量。1．深吸氣量

從平靜呼氣末作最大吸氣時所能吸入的氣量為深吸氣量，它是潮氣量和補吸氣量之和。83（二）肺容量（pulmonarycapacities）82．功能余氣量平靜呼氣末尚存留于肺內(nèi)的氣量為功能余氣量。是余氣量和補呼氣量之和。842．功能余氣量843．肺活量最大吸氣后，從肺內(nèi)所能呼出的最大氣量稱作肺活（vitalcapacity），是潮氣量、補吸氣量和補呼氣量之和。正常成年男性平均約為3500ml，女性為2500ml。853．肺活量8586864.時間肺活量先深吸氣，然后以最快的速度呼出氣體，同時分別測量第1、2、3s末呼出的氣量，計算其所占肺活量的百分數(shù)（正常人各為83%、96%和99%肺活量。)874.時間肺活量878888時間肺活量不僅反映肺活量容量的大小，而且反映了呼吸所遇阻力的變化，所以是評價肺通氣功能的較好指標。89時間肺活量不僅反映肺活量容量的89PulmonaryVolumesAndCapacities628.3-629.1A.PulmonaryVolumes1.Thetidalvolumeisthevolumeofairinspiredorexpiredwitheachnormalbreath;itamountstoabout500milliliters.90PulmonaryVolumesAndCapaciti2.Theinspiratoryreservevolumeisthemaximumextravolumeofairthatcanbeinspiredoverandabovethenormaltidalvolume;itisusuallyequaltoabout3000milliliters.912.Theinspiratoryreservevol3.Theexpiratoryreservevolumeisthemaximumextravolumeofairthatcanbeexpiredbyforcefulexpirationaftertheendofanormaltidalexpiration;thisnormallyamountstoabout1100milliliters.923.Theexpiratoryreservevolu4.Theresidualvolumeisthevolumeofairremaininginthelungsafterthemostforcefulexpiration.Thisvolumeaveragesabout1200milliliters.934.TheresidualvolumeisthePulmonaryCapacitiesIndescribingeventsinthepulmonarycycle,itissometimesdesirabletoconsidertwoormoreofthevolumestogether.Suchcombinationsarecalledpulmonarycapacities.

94PulmonaryCapacities94Thevitalcapacityequalstheinspiratoryreservevolumeplusthetidalvolumeplustheexpiratoryreservevolume.Thisisthemaximumamountofairapersoncanexpelfromthelungsafterfirstfillingthelungstotheirmaximumextentandthenexpiringtothemaximumextent(about4600milliliters).95Thevitalcapacityequalsthe

Thetotallungcapacityisthemaximumvolumetowhichthelungscanbeexpandedwiththegreatestpossibleeffort(about5800milliliters);itisequaltothevitalcapacityplustheresidualvolume.96ThetotallungcapacityisthAllpulmonaryvolumesandcapacitiesareabout20to25percentlessinwomenthaninmen,andtheyaregreaterinlargeandathleticpeoplethaninsmallandasthenic無力的people.97AllpulmonaryvolumesandcapaTo

performaforcedvitalcapacity(FVC)maneuver,thesubjectinhalestototallungcapacity,exhalesasforcefullyand

rapidlyaspossibletoresidualvolume,andthenreturnstoTLCbyarapidforcefulinhalation.

98ToperformaforcedvitalcapaDuringforcedinspiration,flowincreasesrapidlyaboveresidualvolumebecausetheinspiratorymusclesfunctionmostadvantageouslyat

lowlungvolumes.Asinspirationprogresses,flowremainshighbecauseairwayresistancefallsaslungvolumeincreases.NearTLCflowdecreasesastheinspiratorymusclesshorten,andinspiratoryforce

decreases.

99Duringforcedinspiration,flo=12~18500=6~9L/min四、肺通氣量（一）每分通氣量和每分最大通氣量每分通氣量=呼吸頻率潮氣量100=12~18500四、肺通氣量（一）每分通氣量和每分最大通Theminuterespiratoryvolumeisthetotalamountofnewairmovedintotherespiratorypassageseachminute;thisisequaltothetidalvolumetimestherespira-toryrate.Thenormaltidalvolumeisabout500milliliters,andthenormalrespiratoryrateisabout12breathsperminute.Therefore,theminuterespiratoryvolumeaveragesabout6L/min.

101Theminuterespiratoryvolume每分最大通氣量盡力作深快呼吸時，每分鐘所能吸入或呼出的最大氣量為最大通氣量。102每分最大通氣量102（二）無效腔（deadspace)和肺泡通氣量生理無效腔{解剖無效腔（150ml）肺泡無效腔103（二）無效腔（deadspace)和肺泡通氣量生理無效腔Deadspace636.5-6a.Anatomicdeadspaceisthevolumeoftheconductingairways.isnormallyapproximately150ml104Deadspace104Someoftheairapersonbreathesneverreachesthegasexchangeareasbutinsteadgoestofillrespiratorypas-sageswheregasexchangedoesnotoccur,suchasinthenose,pharynx,andtrachea.105SomeoftheairapersonbreatThisairiscalleddeadspaceairbecauseitisnotusefulforthegasexchangeprocess;thespaceintherespiratorypassageswherenogasexchangetakesplaceiscalledthedeadspace.106ThisairiscalleddeadspaceNormalDeadSpaceVolume.Thenormaldeadspaceairinayoungadultmanisabout150milliliters.Thisincreasesslightlywithage.107NormalDeadSpaceVolume.TheThevolumeofallthespaceoftherespiratorysystembesidesthealveoliandtheirothercloselyrelatedgasexchangeareas;thisspaceiscalledtheanatomicdeadspace.108Thevolumeofallthespaceof

Onoccasion,someofthealveolithemselvesarenonfunctionalorareonlypartiallyfunctionalbecauseofabsentorpoorbloodflowthroughadjacentpulmonarycapillaries.Therefore,fromafunctionalpointofview,thesealveolimustalsobeconsidereddeadspace.109Onoccasion,someofthealveWhenthealveolardeadspaceisincludedinthetotalmeasurementofdeadspace,thisiscalledphysiologicdeadspace,incontradistinctiontotheanatomicdeadspace.110WhenthealveolardeadspaceiInanormalperson,theanatomicandphysiologicdeadspacesarenearlyequalbecauseallalveoliarefunctionalinthenormallung,butinapersonwithpartiallyfunctionalornonfunctionalalveoliinsomepartsofthelungs,sometimesthephysiologicdeadspaceisasmuchas10timesthevolumeoftheanatomicdeadspace,or1to2liters.111Inanormalperson,theanatomAlveolarventilationperminuteisthetotalvolumeofnewairenteringthealveoliandadjacentgasexchangeareaseachminute.Itisequaltotherespiratoryratetimestheamountofnewairthatenterstheseareaswitheachbreath.112AlveolarventilationperminutVA=Freq.(VT-V0)whereVAisthevolumeofalveolarventilationperminute,Freqisthefrequencyofrespirationperminute,VTisthetidalvolume,andV0isthephysiologicdeadspacevolume.113VA=Freq.(VT-V0)113Thus,withanormaltidalvolumeof500milliliters,anormaldeadspaceof150milliliters,andarespiratoryrateof12breathsperminute,alveolarventilationequals12X(500-150),or4200ml/min.114Thus,withanormaltidalvoluAlveolarventilationisoneofthemajorfactorsdeterminingtheconcentrationsofoxygenandcarbondioxideinthealveoli.115Alveolarventilationisoneof每次吸入的氣體，一部分留在從鼻至呼吸性細支氣管之間的呼吸道內(nèi)，這部分氣體不參與肺泡與血液的氣體交換，故稱為解剖無效腔，其容積約為150ml。116每次吸入的氣體，一部分留在從鼻至呼吸性細支氣管之間的呼吸道內(nèi)進入肺泡內(nèi)的氣體，也可因血流在肺內(nèi)分布不均而未能都與血液進行氣體交換，未能發(fā)生氣體交換的這一部分肺泡容量稱為肺泡無效腔。117進入肺泡內(nèi)的氣體，也可因血流在117150ml350ml500ml118150ml350ml500ml118?肺泡通氣量每分鐘進入肺泡，能與血液進行氣體交換的新鮮氣體量。肺泡通氣量=（潮氣量-無效腔）呼吸頻率119?肺泡通氣量每分鐘進入肺泡，能與血液進行氣體交換的新鮮氣體深慢呼吸和淺快呼吸的效率比較呼吸頻率（次/min）潮氣量（ml）肺通氣量（ml/min）肺泡通氣量（ml/min）126245001000250600060006000420051002400120深慢呼吸和淺快呼吸的效率比較呼吸頻率（次/min）潮氣量（mrespiration第五章呼吸生理121respiration第五章呼吸生理112221.外呼吸

肺通氣（外界空氣與肺泡之間的氣體交換過程）肺換氣(肺泡與肺毛細血管之間的氣體交換過程）呼吸的三個基本環(huán)節(jié)1231.外呼吸呼吸的三個基本環(huán)節(jié)3氣體在血液中的運輸3.內(nèi)（組織）呼吸血液與組織、細胞之間的氣體交換過程124氣體在血液中的運輸4肺通氣和肺換氣125肺通氣和肺換氣5Thegoalsofrespirationaretoprovideoxygentothetissuesandtoremovecarbondioxide.Toachievethesegoals,respirationcanbedividedintofourmajorfunctionalevents:126Thegoalsofrespirationaretpulmonaryventilation,whichmeanstheinflowandoutflowofairbetweentheatmosphereandthelungalveoli;(2)diffusionofoxygenandcarbondioxidebetweenthealveoliandtheblood;127pulmonaryventilation,whichm(3)transportofoxygenandcarbondioxideinthebloodandbodyfluidstoandfromthecells;and(4)regulationofventilationandotherfacetsofrespiration.Thischapterisadiscussionofpulmonaryventilation.128(3)transportofoxygenandca第一節(jié)肺通氣129第一節(jié)肺通氣9一、實現(xiàn)肺通氣的結構特點及功能鼻、咽、喉、氣管直到終末細支氣管{上呼吸道{下呼吸道130一、實現(xiàn)肺通氣的結構特點及功能鼻、咽、喉、氣管直到終末131111321213313二、肺通氣原理134二、肺通氣原理14（一）肺通氣的動力直接動力：肺泡與大氣之間的壓力差

原動力:呼吸運動呼吸肌收縮、舒張所造成的胸廓的擴大和縮小，稱為呼吸運動。135（一）肺通氣的動力151．呼吸運動（1）吸氣運動：膈肌收縮時中部下移，增大了胸腔的上下徑，肺容積隨之增大，產(chǎn)生吸氣。

平靜呼吸時膈肌收縮造成的通氣量占總通氣量的4/5。1361．呼吸運動1613717當肋間外肌收縮時，增大了胸腔的前后徑和左右徑，肺容積隨之增大,產(chǎn)生吸氣。138當肋間外肌收縮時，增大了胸181391914020（2）呼氣運動：平靜呼氣時，因膈肌和肋間外肌舒張，肺依靠本身的回縮力量而回位，產(chǎn)生呼氣。141（2）呼氣運動：21

用力呼吸：除上述肌肉外，有更多的吸氣肌與呼氣肌參與呼吸運動。142用力呼吸：22用力呼吸{吸氣（主動）膈肌和肋間外肌收縮，胸鎖乳突肌、斜角肌也收縮呼氣（主動）膈肌和肋間外肌舒張，腹壁肌肉、肋間內(nèi)肌收縮

平靜呼吸{吸氣（主動）膈肌和肋間外肌收縮

呼氣（被動）膈肌和肋間外肌舒張143用力呼吸{吸氣（主動）膈肌和肋間外肌收縮，胸鎖乳突肌、斜呼吸運動{腹式呼吸胸式呼吸膈肌舒縮引起的呼吸運動伴以腹壁的起伏，所以稱為腹式呼吸（abdominalbreathing）。144呼吸運動{腹式呼吸胸式呼吸膈肌舒縮引起的呼吸運動伴以腹由肋間肌舒縮使肋骨和胸骨運動所產(chǎn)生的呼吸運動，稱為胸式呼吸。Thoracicbreathing145由肋間肌舒縮使肋骨和胸骨運251.MechanicsOfPulmonaryVentilation627.4-628.3A.MusclesThatCauseLungExpansionandContraction629.2-630.21461.MechanicsOfPulmonaryVentThelungscanbeexpandedandcontractedintwoways:bydownwardandupwardmovementofthediaphragmtolengthenorshortenthechestcavityandbyelevationanddepressionoftheribstoincreaseanddecreasetheantero-posteriordiameterofthechestcavity.147ThelungscanbeexpandedandNormalquietbreathingisaccomplishedalmostentirelybythefirstofthetwomethods,thatis,bymovementofthediaphragm.Duringinspiration,contractionofthediaphragmpullsthelowersurfacesofthelungsdownward.148NormalquietbreathingisaccoThen,duringexpiration,thediaphragmsimplyrelaxes,andtheelasticrecoilofthelungs,chestwall,andabdominalstructurescompressesthelungs.149Then,duringexpiration,thedDuringheavybreathing,however,extraforceisachievedmainlybycontractionoftheabdominalmuscles,whichpushestheabdominalcontentsupwardagainstthebottomofthediaphragm.150Duringheavybreathing,howeveThesecondmethodforexpandingthelungsistoraisetheribcage.whentheribcageiselevated,makingtheantero-posteriorthicknessofthechestabout20percentgreaterduringmaximuminspirationthanduringexpiration.151ThesecondmethodforexpandinTherefore,allthemusclesthatelevatethechestcageareclassifiedasmusclesofinspiration,andthemusclesthatdepressthechestcageareclassifiedasmusclesofexpiration.Themostimportantmusclesthatraisetheribcagearetheexternalintercostals.152Therefore,allthemusclesthaThemusclesthatpulltheribcagedownwardduringexpirationare(1)theabdominalrecti,whichhavethepowerfuleffectofpullingdownwardonthelowerribsatthesametimethattheyandtheotherabdominalmusclescompresstheabdominalcontentsupwardtowardthediaphragm,and(2)theinternalintercostals.153ThemusclesthatpulltheribAstheexternalintercostalstheycontract,theypullribsforward,andthiscausesleverageontheribstoraisethemupward,therebycausinginspiration.Theinternalintercostalsfunctionexactlyoppositely,functioningasexpiratorymuscles,becausetheyanglebetweentheribsintheoppositedirectionandcauseoppositeleverage.154Astheexternalintercostalst2．肺內(nèi)壓肺內(nèi)壓是指肺泡內(nèi)的壓力。吸氣初，肺內(nèi)壓低于大氣壓，空氣進入肺泡。呼氣初，肺內(nèi)壓高于大氣壓，肺內(nèi)氣體流出。吸氣末和呼氣末，肺內(nèi)壓和大氣壓相等。1552．肺內(nèi)壓35Alveolarpressureisthepressureoftheairinsidethelungalveoli.Whentheglottis聲門isopenandnoairisflowingintooroutofthelungs,thepressuresinallpartsoftherespiratorytree,allthewaytothealveoli,areequaltoatmosphericpressure,whichisconsideredtobethezeroreferencepressureintheairways–thatis,0centimeterswaterpressure.156AlveolarpressureisthepressTocauseinwardflowofairintothealveoliduringinspiration,thepressureinthealveolimustfalltoavalueslightlybelowatmosphericpressure(below0).157TocauseinwardflowofairiDuringnormalinspiration,alveolarpressuredecreasestoabout-1centimeterofwater.Thisslightnegativepressureisenoughtopull0.5literofairintothelungsinthe2secondsrequiredfornormalquietinspiration.158Duringnormalinspiration,alvDuringexpiration,oppositechangesoccur:Thealveolarpressurerisestoabout+1centimeterofwater,andthisforcesthe0.5literofinspiredairoutofthelungsduringthe2to3secondsofexpiration.159Duringexpiration,oppositech3.胸內(nèi)壓胸膜腔內(nèi)的壓力稱為胸內(nèi)壓。1603.胸內(nèi)壓胸膜腔內(nèi)的壓力稱為胸內(nèi)壓。4016141胸膜腔內(nèi)壓比大氣壓低，為負壓。平靜呼氣末胸膜腔內(nèi)壓約為-5—-3mmHg，吸氣末約為-10—-5mmHg。162胸膜腔內(nèi)壓比大氣壓低，為負壓。42胸內(nèi)壓=大氣壓-肺回縮力163胸內(nèi)壓=大氣壓-肺回縮力43胸內(nèi)壓=肺內(nèi)壓-肺彈性回縮力=大氣壓-肺彈性回縮力若以1個大氣壓為0，則胸膜腔內(nèi)壓=－肺彈性回縮力164胸內(nèi)壓=肺內(nèi)壓-肺彈性回縮力4416545Pleuralpressureisthepressureofthefluidinthenarrowspacebetweenthelungpleuraandthechestwallpleura.166PleuralpressureisthepressuPleuralpressureisnormallyaslightlynegativepressure.Thenormalpleuralpressureatthebeginningofinspirationisabout-5centimetersofwater,whichistheamountofsuctionthatisrequiredtoholdthelungsopentotheirrestinglevel.167PleuralpressureisnormallyaThen,duringnormalinspiration,theexpansionofthechestcagepullsoutwardonthelungswithstillgreaterforceandcreatesastillmorenegativepressuretoanaverageofabout-7.5centimetersofwater.168Then,duringnormalinspiratio（二）肺通氣的阻力{彈性阻力（70%）非彈性阻力（30%）169（二）肺通氣的阻力{彈性阻力（70%）非彈性阻力（30%）41、彈性阻力和順應性（1）彈性阻力彈性組織在外力作用下變形時，有對抗變形和彈性回位的傾向，為彈性阻力。1701、彈性阻力和順應性（1）彈性阻力50（2）順應性(compliance)順應性是指在外力作用下彈性組織的可擴張性。容易擴張者，順應性大，彈性阻力?。环粗畡t相反。

171（2）順應性(compliance)順應性是指在外力作用下彈可見順應性（C）與彈性阻力（R）成反變關系：

C=1/R172可見順應性（C）與彈性阻52順應性用單位壓力變化（△P）所引起的容積變化（△V）來表示，單位是L/cmH2O，即C=△V/△PL/cmH2O。173順應性用單位壓力變化（△P）53Complianceintherespiratorysystem631.2-633.1describesthedistensibilityofthelungsandchestwall.isinverselyrelatedtoelastance,whichdependsontheamountofelastictissue.isthechangeinvolumeforagivenchangeinpressure.174Complianceintherespiratory?肺的彈性阻力{肺表面張力（2/3）肺組織彈性（1/3）(3)肺的彈性阻力的來源175?肺的彈性阻力{肺表面張力（2/3）肺組織彈性（1/3）(肺組織的彈性主要來肺組織的彈性纖維和膠原纖維。176肺組織的彈性主要來肺組織的彈性纖維和膠原纖維。56Resistencetopulmonaryventilation

633.2-634.4Resistantforcesofthelungs.Thesecanbedividedintotwoparts:(1)theelasticforcesofthelungtissueitself177ResistencetopulmonaryventilTheelasticforcesofthelungtissuearedeterminedmainlybytheelastinandcollagenfibersinterwovenamongthelungparenchyma.(2)theelasticforcescausedbysurfacetensionofthefluidthatlinestheinsidewallsofthealveoliandotherlungairspaces.178TheelasticforcesofthelungNatureofLungElasticRecoilTheelasticrecoilofthelungconsistsoftwokindsof

forces－tissueforcesandsurfacetensionforces.The

elasticityoflungtissueisdueprincipallytoelastin彈性蛋白fibers

inalveolarwallsandsurroundingsmallairways.

179NatureofLungElasticRecoil5?肺泡表面張力肺泡內(nèi)壁有一薄層液體，它與肺泡內(nèi)氣體形成了液-氣交界面，這里存在減小液-氣界面的力，使肺泡趨于縮小，稱為肺泡表面張力。180?肺泡表面張力肺泡內(nèi)壁有一薄層液體，它與肺泡60?肺泡表面活性物質是由肺泡Ⅱ型細胞分泌的一種復雜的