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50 Cards in this Set
- Front
- Back
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Functions of muscular tissue |
Produce body movements Maintain posture Heat production Protection |
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Skeletal muscular tissue is attached to ____ by _____ |
Bone by tendon |
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Microscopic feature of skeletal muscular tissue |
Striated Long Cyclindrical Unbranched Peripherally located nuclei |
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Skeletal muscular tissue nervous control |
Somatic nervous system - voluntary |
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Skeletal muscles arise from |
Fusion of hundred or more my oblast during embryonic development |
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Satellite cells |
Part of myoblast that does not fuse or differentiate but remains mesenchymal cells Located on the external surface of muscle fibers inside the developing external lamina Proliferate and produce new muscle fibers following muscle injury |
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Skeletal muscle fiber length |
Very long, vary greatly Few centimeters to 30-40 cm |
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Skeletal muscle fiber diameter |
Very large 10-100 um |
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Transverse t tubules |
Long invaginations in the sarcolemma that penetratate into the sarcoplasm Aligned with each A-I band junction Filled with interstitial fluid Ensures action potential to excite the whole muscle fiber at the same instant |
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Nuclei skeletal muscle |
100 or more Found beneath sarcolemma |
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Glycogen |
Large molecule composed of many glucose molecules Can be used for ATP synthesis |
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Myoglobin |
Red colored protein found only in muscle Binds O from interstitial fluid Releases O needed by the mitochondria for ATP synthesis |
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Mitochondria |
Lie in rows throughout fiber Close to contractile muscle proteins |
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Sarcoplasm reticulum |
Fluid filled system of membranous sacs which encircle each myofibril Dilated end sacs called terminal cisterns butt against T tubules at both sides Abundant in skelatal muscle fiber Relaxed - store Ca Release of Ca ions triggers muscle contraction |
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Mtofibrils |
Contractile organelles of skeletal muscle Arranged in parallel bundles 2um in diameter and extend the entire length of a muscle fiber Contain thick and thin filaments |
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Sarcomere |
Basic functional unit of myofibril |
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Z disc |
Narrow plate shaped regions of dense material Separate one sarcomere from the next |
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A band |
Dark middle part of sarcomere Extend the entire length of thick filaments Includes part of thin filaments that overlap thick filaments |
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I band |
Lighter less dense area Contains remainder of thin filaments Z disc passes through center |
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H zone |
Narrow region in center Contains thick and no thin filaments |
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M line |
Region in center of H zone Contains proteins that hold thick filaments together |
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Epimysium |
Outer layer Entire muscle Dense irregular connective tissue |
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Perimysium |
Separates 10 to 100 muscle fibers Groups into fascicles Dense irregular collagenous connective tissue |
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Endomysium |
surrounds individual muscle fiber Reticular fibers |
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Myosin |
Thick filament Tail and two myosin heads Motor protein |
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Actin |
Thin filaments Myosin binding site Motor protein |
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Regulatory protein |
Help switch contraction on and off |
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Tropomyosin |
Component of thin filaments Covers Myosin binding site when relaxed |
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Troponin |
Thick filament |
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Structural proteins |
Keep thick and thin in proper alignment Give elasticity and extensibility Link myofibril to sarcolemma and extracellular matrix |
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Titin |
Connects z disc to M line Stabilize thick filaments Stretch and spring back unharmed Accounts for extensibility and elasticity of myofibril |
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Alpha actinin |
Protein of z disc Attaches to actin molecules and to titin molecules |
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Myomesin |
Forms M line Binds titin connects adjacent thick filaments |
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Nebulin |
Wraps around thin Anchor thin to z discs Regulates length of thin during development |
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Dystrophin |
Link thin filaments to integral proteins of sarcolemma Reinforce sarcolemma Transmit tension to tendons |
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Location of cardiac muscle |
Heart and large vessels attached to heart |
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Microscopic features of cardiac muscle |
Branched cylindrical Uni or binucleated Centrally located nucleus Striated Intercalated discs |
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Cardiac muscle fiber length |
Long 50 to 100 um |
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Cardiac muscle diameter |
Large 10 to 20 um |
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Intercalated discs |
Contain gap junctions and desmosomes |
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Cardiac muscle structure |
Larger t tubules found at z lines Sarcoplasmic reticulum less developed |
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Connective tissue of cardiac muscle |
Endomysium Subendocardial and subpericardial ct |
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Location of smooth muscle |
Walls of hollow viscera Airways Blood vessels Iris Cillary body of eye Arrector pili of hair follicles |
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Microscopic features of smooth muscle |
Fusiform Spindle shaped not striated Centrally located nucleus |
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Motor control of smooth muscle |
Autonomic Involuntary |
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Length of smooth muscle fiber |
Intermediate 30 to 200 um |
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Diameter of smooth muscle |
Small 3 to 8 um |
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Structure of smooth muscle |
No regular pattern of overlapping Actin and Myosin form lattice and insert into dense bodies in the sarcoplasm Gap junctions allow ionic communication No t tubules Very little SR Caveolae |
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Regulatory proteins of smooth muscles |
Myosin light chain kinase Calmodulin |
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Connective tissue of smooth muscle |
Endomysium and less organizer CT sheaths |
