骨骼肌肉課件

SkeletalMuscleStructureandFunctionChapter19骨骼肌肉--MuscletypesSkeletalmuscleStriatedVoluntary400skeletalmuscles40-50%oftotalbodyweightFunctionsLocomotionandbreathingPosturalsupportHeatproductionduringcoldstressSmoothmuscleNon-striatedTonalcontrolCardiacmuscleElectricallycoupledcells骨骼肌肉--StructureofSkeletalMuscle:

ConnectiveTissueCoveringEpimysiumSurroundsentiremusclePerimysiumSurroundsbundlesofmusclefibers(Fascicles)EndomysiumSurroundsindividualmusclefibers骨骼肌肉--StructureofSkeletalMuscle:

MicrostructureSarcolemmaMusclecellmembraneMyofibrilsThreadlikestrandswithinmusclefibersActin(thinfilament)TroponinTropomyosinMyosin(thickfilament)骨骼肌肉--StructureofSkeletalMuscle:

MicrostructureAbandAnisotropic(dark)IbandIsotropic(light)ZdiscZwischenscheibe(betweenzone)HzoneHellerscheibe(cleardisc)骨骼肌肉--StructureofSkeletalMuscle:TheSarcomereAI骨骼肌肉--StructureofSkeletalMuscle:TheSarcomere骨骼肌肉--Z-disc

-actininThickFilamentsMyosin

Figure19.7StructureofSkeletalMuscle:TheSarcomereThinFilamentsActinTroponin(CTI)Tropomyosin骨骼肌肉--StructureofSkeletalMuscle:TheSarcomereNebulindefineslengthofthinfilamentTropomodulincapsthinfilamentTitincentersthickfilament骨骼肌肉--TheNeuromuscularJunctionSynapsebetweenmotorneuronandmusclefiberneuromuscularcleftMotorendplatePocketformedaroundmotorneuronbysarcolemmaAcetylcholineCausesend-platepotential(EPP)Depolarizesmusclefiber骨骼肌肉--骨骼肌肉--StructureofSkeletalMuscle:TheSarcoplasmicreticulumSarcoplasmicreticulumStoragesitesforcalciumTransversetubules骨骼肌肉--Severaltypesofionchannel骨骼肌肉--骨骼肌肉--骨骼肌肉--Figure19.9Cross-BridgeFormationinMuscleContraction骨骼肌肉--Summary骨骼肌肉--SarcomerelengthLengthofthickfilament1.6

mLengthofthinfilament1.0

m骨骼肌肉--Muscular

ContractionTheslidingfilamentmodelMovementoftheactinfilamentoverthemyosinfilamentFormationofcross-bridgesbetweenactinandmyosinfilamentsReductioninthedistancebetweenZ-discsofthesarcomereActinMyosinActinin(z-disc)骨骼肌肉--骨骼肌肉--EnergyforMuscleContractionATPisrequiredformusclecontractionMyosinATPasebreaksdownATPasfibercontractsSourcesofATPPhosphocreatine(PC)GlycolysisOxidativephosphorylation骨骼肌肉--骨骼肌肉--骨骼肌肉--骨骼肌肉--Figure19.11骨骼肌肉--PropertiesofMuscleFibersBiochemicalpropertiesOxidativecapacityTypeofATPaseContractilepropertiesMaximalforceproductionSpeedofcontractionMusclefiberefficiency骨骼肌肉--IndividualFiberTypesFastfibersTypeIIafibersIntermediatespeedFast-oxidative/glycolyticTypeIIbfibersFast-twitchGlycolyticSlowfibersTypeIfibersSlow-twitchOxidative骨骼肌肉--Table19.2骨骼肌肉--ComparisonofMaximalShorteningVelocitiesBetweenFiberTypesSO FOG FG 骨骼肌肉--HistochemicalStainingofFiberType

MyosinATPasestainingTypeIIaType

IIbTypeI骨骼肌肉--FiberTypesandPerformancePowerathletesSprintersPossesshighpercentageoffastfibersEnduranceathletesDistancerunnersHavehighpercentageofslowfibersOthersWeightliftersandnonathletesHaveabout50%slowand50%fastfibers骨骼肌肉--SOFOG/FG骨骼肌肉--AlterationofFiberTypebyTrainingMostlydeterminedgenetically:-(EndurancetrainingCannotchangefastfiberstoslowfibersCanresultinshiftfromTypeIIbtoIIafibersMoreoxidative骨骼肌肉--Preferentialrecruitmentoffibersbyexercisetype骨骼肌肉--Higher%oftype1fiberselevatesVO2maxTrueofbothathletesandnon-athletes骨骼肌肉--Foragivenrateofshortening,highVmaxmuscleproducesmoreforceForce=tension(load)VelocityofShorteningVmax骨骼肌肉--Foragivenrateofshortening,highVmaxmuscleproducesmorepower.Work=forcexdistancePower=work/time骨骼肌肉--Highpowermus