TEAS Prep Notes - Muscular System

muscles Pull on BonesTendons attach muscles to bonesorigin: part of attachment thatdoesn't move during contractionskeletal muscles movebones when they shortenor lengthenInsertion: Point of attachmentthat DOES moveLigamentduring contractionconnect boneto bonemain types of contraction1isotonic = shortening"same tension"2Isometric = no length change, butNo contraction, you'd"same length"fall down (crushing)3Eccentric = lengthening calves arecommon to do this whenhiring uphill, w/ocontraction tearingTypes of musclewould occurskeletal voluntary containstriationsSmouth - Invcuuntary, lack striationsundiac. only found in heart, is striated,contains T-tubles & myotibrils, is branched meadmuscle AnatomyTendon: connects muscle to boneIskeletal muscle> muscle Eascides > muscleFibers myotibili sarcomeremotor unit: one motor neuron and all themuscle fibers that it controls Rectus Femorishas ~800 motor units, each necron controlsabout 1000 cellsmotor units controls How MANY CELLS CONTRACTEvents inside of muscle cells determineFascica muscle (group fibers ofHow HARD each cell contractssimilar slow least!either intermediate twichEpimysium :"upon muscle"HAasurrounds the entire mode6BPerimysium"around muscle",surrounds groups ofmyofibillscarcolemnamuscle fibers (cell)PACK inside of cell(cell membrane)Endomysiumcontain contractiveEndomysium:units, sarcomeresinside muscle"AE wantz line - seperatessarcomeresstriations (stripesare caused by overlap700A Bandb bandun us in whenmyosin: Thickof myosin & actin.area2.00motor proteinCritical for contraction6006oasCROO000Actin thincanmuscle proteinwhat happens during muscle contraction?myosin head binds to actin, >horteningSARCOMERE can have 2000 inthe sarcomere as the acrin is pulled overAssone myotibiliDOBthe myosinwww.sciencewithsusanna.comIsotonic contractionas*Elongation of actin & myosin fivamentsEccentinc contractionoccur in both contraction & Relaxation(make you more sore due 10)small tears in sarcomere 6Neuromuscular Junction -> axonterminal+synaptic cleftmuscle fibeaward orAlca"country (ACa):ismotor nervefrom spinal card /⑆spinal nerve or cranalnerveAMteamingsarcoplasmicReticulum (SR)once Ach binds to thereleases Ca2+ whenreceptors. the ENTIRE musclecell depotarizesSTREET gettmuscle cell isdepolarizedcalcium will bind toboth directionstroponin. Thisallows myosinTragoninto bind to adth.Activeintopurpose? throughout convaction Allow the tomyosinusually in a castExcitation contraction couplingAtrophy: muscles not used regularly&will cause this, myofibrils will shrinkDepolarizationmechanical movementof myosin on actinresulting in weaker muscle contractionsas a result of cermentationBuildup of lactic add impairs the muscle's abilityto contrast due to changes in muscle tissue PHmuscle contractionmuscle Relaxationmotor neurons signalcontraction a antagonistic muscleto retease aatylcholine intoRemoval of acetylcholine from thewww.sciencewithsusanna.comthe neuromuscular junctionNeuromuscular junctionThan triggers release of calciumRemoval of ogtoplaspt from me cytoplasminto the cytoplasm of muscle cellcalciumat a musclecell cross - Bridge cycleThis proteinmeasured in bloodafter suspected 0 attack. At rest, actin is NOTbound to myusin (TroponinActinanDepolorization releases Ca21 from saraplosmic myosin reticulum,is in the way)ca 2t binds to ttopaninlactin andTOBinD ACTINmyosinATP > ADP(hydrolysis)changes myosinconfiguration to recock"it For next cyclecATPEJECTED!POWERSTROKEADPas myosinmoves ACTIN!binds to actinATP causes myosin to fall off actinATP binds myosinATPmyosin is stuck on ACTIN untilOxygen debt: During heavy exercise, pyruvic acid builds up in musdes convertsfaster than it can be oxydized. This pyruvic acid tolactic aud. A high level of oxygen is required even after theexercise finishes to oxidate this lactic acidsteps before & after an Action Potential1 Depolarization2 Threshod2 Reporarization4Retractory period