Muscular-System.pdf - ANATOMY AND PHYSIOLOGY 2. Cardiac...

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ANATOMY AND PHYSIOLOGYFINPage 1Muscular SystemMuscle are responsible for all types ofbody movementThree (3) basic muscle types are found in thebody1. Skeletal Muscle2. Cardiac Muscle
ANATOMY AND PHYSIOLOGYFINPage 23. Smooth MuscleI.Muscle TypesSkeletal and smooth muscle cells areelongated (muscle cell = muscle fiber)Contraction and shortening of musclesare due to the movement ofmicrofilamentsAll muscles share some terminologyoPrefixesmyoandmys- referto “muscle”oPrefixsacro-refers to “flesh”Skeletal muscleMost skeletal muscle fibers are attachby tendons to bonesSkeletal muscle cells are large, cigar-shaped, and multinucleateAlso known asstriated musclebecauseof it’s obvious stripesAlso known asvoluntary musclebecause it is the only muscle tissuesubject to conscious controlSkeletal muscle are surrounded andbundled by connective tissueoEndomysiumencloses a singlemuscle fiberoPerimysiumwraps around afascicle (bundle) of musclefibersoEpimysiumcovers the entireskeletal muscleoFasciaon the outside of theepimysium
ANATOMY AND PHYSIOLOGYFINPage 3I.Muscle TypesThe epimysium of skeletal muscleblends into a connective tissueattachmentoTendonscordlike structuresMostly collagen fibersOften cross a jointbecause of theirtoughness and smallsizeoAponeurosessheetlikestructuresAttach musclesindirectly to bones,cartilages, orconnective tissuecoveringsWhereas all muscle types producemovement, skeletal muscle has threeother important roles:oMaintain posture and bodypositionoStabilize jointsoGenerate heatATPADP + PII. Microscopic Anatomy of Skeletal MuscleSarcolemmaspecialized plasmamembraneMyofibrilslong organelles insidemuscle celloLight (I) bands and dark (A)bands give the muscle it’sstriated (banded) appearanceBanding pattern of myofibrilsoI band = light bandContains only thinfilaments (actin)Z disc is a midlineinterruptionA band =dark bandoContains the entire length ofthe thick filaments (myosin)Sarcomerecontractile unit of a musclefiberoStructural and functional unit ofskeletal nuscleOrganization of the sarcomereoMyofilaments produce banding(striped) patternThick filaments =myosin filamentsThin filaments = actinfilamentsThick filaments = myosin filamentsoComposed of protein myosinoContain ATPase enzymes tosplit ATP to release energy formuscle contractionsoPossess projections known asmyosinheadsoMyosin heads are known ascross bridgeswhen they linkand thin filaments duringcontraction
ANATOMY AND PHYSIOLOGYFINPage 4II. Microscopic Anatomy of Skeletal MuscleThin filaments = actin filamentsoComposed of the contractileprotein actinoActinis anchored to the Z discAt rest, within the A band there is azone that lack actin filaments called theH zoneDuring contraction, H zones disappearas actin and myosin filaments overlapSacroplastoc reticulum (SR)oSpecialized smooth

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Term
Summer
Professor
Jane Julio

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