MUSCLE TISSUE

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MUSCLE TISSUE
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Muscle Tissue 

• If it contracts, it's muscle
• Muscle tissue is categorized on the basis of a
  functional property the ability of its cells to
  contract.
• consists of the contractile protein fibrils actin
  and myosin. Muscle is responsible for movement of
  the body and changes in the size and shape of
  internal organs.
• Muscle cells are generally referred to as muscle
  fibres.
• Muscle fibres are typically arranged in parallel
  arrays allowing them to work together effectively

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The three types of muscle

• Three types of muscle tissue can be identified
  histologically
• skeletal muscle (striated muscle, voluntary),
• cardiac muscle
• smooth muscle (non-striated muscle, involuntary).

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Skeletal muscle

• Skeletal muscle constitutes the muscle that is
  attached to the skeleton and controls motor
  movements and posture.

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Skeletal Muscle

• Skeletal muscle fibres (cells) are multinucleated
  
• They are filled with longitudinally arrayed
  subunits called myofibrils.
• The myofibrils are made up of the myofilaments
  myosin (thick filaments) and actin (thin
  filaments).
• The striations reflect the arrangement of actin
  and myosin filaments and support structures.
• The individual contractile units are
  called sarcomeres.

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Skeletal Muscle Summary

• Summary Skeletal muscle fibres bear obvious
  striations, have many peripherally located
  nuclei, are of the same thickness throughout
  their length and do not branch.

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Skeletal Muscle
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Skeletal Muscle
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Cardiac Muscle

• Cardiac muscle is the type of muscle found in the
  heart
• Cardiac muscle is intrinsically contractile but
  is regulated by autonomic (unconscious) and
  hormonal stimuli.

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Cardiac Muscle Summary

• Striations are present (actin and myosin)
• Greater number of mitochondria present
• Cardiac muscle cells have only one or two nuclei,
  which are centrally located.
• Cardiac muscle cells are joined to one another in
  a linear array. The boundary between two cells
  abutting one another is called an intercalated
  disc.
• Cardiac muscle fibres are branched

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Cardiac Muscle
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Cardiac Muscle
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Smooth Muscle

• Smooth muscle is the intrinsic muscle of the
  internal organs, iris of the eye and blood
  vessels.
• Like cardiac muscle, smooth muscle fibres are
  intrinsically contractile but responsive to
  autonomic and hormonal stimuli. They are
  specialized for slow, prolonged contraction.

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Smooth Muscle

• Smooth muscle fibres are generally arranged in
  bundles or sheets (no striations)
• A single nucleus is located in the central part
  of the fibre.
• Fibres do not branch.
• Smooth muscle fibres lie over one another in a
  staggered fashion
• Fusiform Shape with tapered ends

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Smooth Muscle
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Musclel Tissue Summary
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Muscle Tissue Summary