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