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Muscle_Tissue

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					                Muscle Tissue
   Characteristics of Muscle
   Responsiveness: to produce chemical signals
    coordinated with electrical charges
   Conductivity: to pass stimulus beyond local area
    to excite contraction
   Contractility: to shorten when stimulated
   Extensibility: to stretch between contractions
   Elasticity: to return to original shape
           Skeletal Muscle
 Skeletal muscle: voluntary striated muscle
  attached to one or more bones
 Striations: caused by overlapping of
  contractile proteins
                 Myofilaments
    Myofilament: long protein cords, fills muscle
     cell
    A myofibril is a bundle of 3 myofilaments
    Myofilaments:
1.   Thick filaments: made of myosin, looks like a
     golf club
2.   Thin Filaments: are composed of two strands
     of proteins, F actin and G actin where G actin
     contains active sites where the head of myosin
     can bind
3.   Elastic filaments: made of titin, flanks the thin
     filament and anchors it to the Z disk
                Striations
 A band (dArk band): consists of thick
  filaments that lay side by side
 I band (L(I)ght band): consists of thin and
  elastic filaments between thick filaments
 H band: a section of the A band that is not
  covered with thin and elastic filaments
 Z disk: a dense protein that anchors thin
  and elastic filaments, central to
  contraction of muscle
                  Striations
   Sarcomere: the functional contractile unit
    located between the Z disks

				
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posted:9/7/2012
language:English
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