Chapter 9 Anatomy and Physiology I.docx - Chapter 9 Anatomy...

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Chapter 9 Anatomy and Physiology ICharacteristics of MusclesoFunctions:MovementPostureJoint stabilityLess likelihood of injuryHeat productionExample is shiveringoAll tissues exhibit:Excitability (irritability)Respond to stimulusContractilityExtensibilityFlexing or stretchingElasticitySkeletal MuscleoVoluntary and striatedStraited by myosin and actin arrangementoUsually attached to boneoMuscle generates tension in muscle fibers and that is follow byexternal tension in order to move a load.oMuscle fiber
Muscle cell with multiple nucleioKnow connective tissue wrappings!Muscle fiber is wrapped by endomysiumPerimysium wraps the fascicleEpimysium is continuous with the tendon and wraps manyfasciclesMuscle fiberoMyofilaments make up a muscle fiber and are made ofmyofilamentsoIn order of largest to smallest:Whole muscleMuscle fascicleMuscle fiber (cell)MyofibrilsMyofilamentsoPlasma membrane is called sarcolemmaoCytoplasm is called sarcoplasm and contains glycogen andmyoglobin for ATP productionoSarcoplasmic reticulum joins with T tubules to form a terminalcistern.Cistern holds calcium like a cistern/ wellSarcoplasmic reticulum is like endoplasmic reticulumTriad is 2 cisterns and 1 tubuleMyofilaments (Actin and Myosin)oTwo kinds:Thick myofilaments2
Multiples myosin stuck togetherBinds to actinThin myofilaments2 strands of actin wound togetherBinds to myosinTropomyosin cover bonding sites during relaxationTroponin binds to calcium and ATP to removetropomyosinContractionoMyosin and actin bind together and engageoSarcomere is shortenedoAn analogy would be a crew of rowers and the oars are myosinwhile the water is actinContraction and relaxationoKey players:Brain and skeletal muscles communicate through motorneurons to contractSpinal cordaxonaxon terminusmuscle fibersAxon terminus and muscle fibers form theneuromuscular junction, but it is not perfectly sealedoSteps:1ststep delivers excitationNerve impulse to motor neuron,Calcium goes into end of motor neuron3
Calcium entry causes ACh (acetylcholine) to bereleased by exocytosis of the motor neuron intosynovial junctionACh binds to receptor on the sarcolemma (muscle

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Term
Fall
Professor
Jones
Tags
Physiology, Anatomy, delayed onset muscle soreness, Muscle fascicle

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