扬州大学：《生理学》课程教学课件（PPT讲稿）第二章 细胞的基本功能 Basic functions of cells-2/2

WELCOMETOHumanPhysiology(LECTURESESSION)Department of PhysiologyYangzhou University School of MedicineSpring2020

WELCOME TO Human Physiology (LECTURE SESSION) Department of Physiology Yangzhou University School of Medicine Spring 2020

CardiacMuscle CellsSkeletalCardiacmusclecellStriatedMuscleSkeletal musclecellSmoothmusclecellSmooth

Muscle Cells

Three Types of Muscle Cells1. Skeletalo Isattached toboneso itisstriatedo Is under voluntary controlMusclecells(fibers)aremultinucleated2. Smootho Is located in the walls of hollow internal structureso Is nonstriatedo Is under involuntary control3. Cardiaco It forms most ofthe hearto It is striated Itisunderinvoluntarycontrolo Itisautorhythmic

Three Types of Muscle Cells

NeuromuscularJunctionSNeuromuscularJunction

Neuromuscular Junction

NeuronmuscularJunctionTheNeuromuscularJunctionTerminalButtonAxonofmotorneuron1.MotorneuronactionpotentialarivesMuscleFibersattheaxonterminalActionpotenitialMyelinsheath2.Ca2+entersvoltage-gatedchannelsAxonTerminak3.Acetylcholinereleasefromvesiclestojunctional cleft4.AcetylcholinebindstoitsreceptorsonAxonterminalTerminalbuttomotorendplateVoltage-gated calciumchannelVesicleofacetylcholineActionpotenitial5.Natentersmusclefibers (musclecells)propagationVoltage-gated Na+ channelin.muscle.fiber营an6.End-platepotentialeachsthreshholdtofireactionpotertialonmusclecellmembranePiasmamembraneMuscle fiber7.DegradationofacetylcholinebyofmusclefiberacetylcholinesteraseAcetyicholine receptor siteXAcetylcholinesteraseNeurotransmitter-gated channelMotorend plate

Neuronmuscular Junction

Disruption of neuromuscular signaling1. Occupationofacetylcholine receptorAxonMitochondriortermina---curareAcetyICoAAcetylcholine2.Inhibitionof acetylcholinesterase (AChEEnzymehSynapticvesicle---organophosphates-pesticides3. Blocking the releasing ofacetylcholine(ACholineCholinergicreceptofromAchvesiclesAcetate---botulinumtoxinPostsynapticAcetyicholinesterase(AChE)cellCurarePesticidesFoodpoison

Disruption of neuromuscular signaling 1. Occupation of acetylcholine receptor - curare 2. Inhibition of acetylcholinesterase (AChE) - organophosphates-pesticides 3. Blocking the releasing of acetylcholine (ACh) from ACh vesicles - botulinum toxin Curare Pesticides Food poison

SkeletalMuscleCellsStructure of a Skeletal MuscleMusclefibre(cell)PerimysiumBloodvesselBoneSarcoplasmicreticulumMusclefibreMyofibrilcellMyosinActinSarcomereFascicleTendonEpimysiurnEndomysium

Skeletal Muscle Cells

MyofibrilIbandAbandIbandZ discHzoneZ discMlinPart of askeletalmusclefiber(cell)SarcolemmaTriad1MitochondrionMyofibrilsMyofibrilTubules ofsarcoplasmicreticulumSarcolemmaTerminal cisternaofthesarcoplasmicreticulumTtubuleSarcoplasm.ThisisthemusclefibercytoplasmItcontainsglycosomes(granulesofglycogen)andtheoxygen-bindingproteincalledmyoglobin..Isisalmostcompletelyfilledwithcontractilefilamentscalledmyofilaments

Myofibril

SarcomereMuscleSarcomereNucleiBundleofMlineZlineZlinemusclefibersSinglemusclefiberThinfilament(cell)ThickfilamentTitinfilamentZ discZdiscMineMyofibril10000000009LightDarkZlinebandband01000ESarcomereSarcomereZoneofZoneofHzoneoverlapoverlapIbandAbandIbandIbandIbandAbandZdisc-alinethatseparatesonesarcomerefromanotherM lineaThickfilamentsM line-central lineofthesarcomerewheremyosinfilamentsareanchored(myosin)Hzone-theareawhereonlymyosinfilamentsarepresent聘Iband-theareawhereonlyactinfilamentsarepresentThinfilamentsaAband-includesoverlappingmyosinandactinfilaments(actin)ZlineZlineHzoneSarcomere

Sarcomere

SarcoplasmicReticulumSystemSarcoplasmicReticulum:Skeletal Muscleonemyofibrilmyofilaments1/2IbanoTtubuleterminalcisternaTerminalcisternaestorescalciumAbandtubules ofsarcoplasmicreticulumtriad1/2IbandSarcoplasmicReticulum.Thisisthesmoothendoplasmicreticulum(SER)inthemusclefiberItisanetworkoftubessurroundingmyofibrilsItreabsorbs calciumionsduringrelaxationItreleasescalciumionstocausecontraction

Sarcoplasmic Reticulum System Terminal cisternae stores calcium