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2011-04-18 02:14:07
muscle tissues

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    • Skeletal
    • Cardiac
    • Smooth
  2. Skeletal Muscle
    • *Comprised of very long muscle cells
    • *Found in the muscles that move the skeleton
    • *Able to be controlled VOLUNTARIY
    • *Display light & dark bands giving appearance of strips or STRIATIONS
  3. Cardic Muscle
    • Found only in the heart
    • Have striations
    • Involuntary muscle
    • Have some neutonal regulation that controls the beating of the heart(subconscious level)
  4. Smooth Muscle
    • Found in the walls of hollow visceral organs e.g:stomach & bladder
    • Lack Striations
    • Can not be consciously regulated or controlled (involuntary)
  5. Characteristics of Muscle Tissue
    • Excitability
    • Contractility
    • Extensibility
    • Elasticity
  6. Excitability
    The ability to receive or respond to stimuli
  7. Contractility
    The ability to shorten forcibly when adequately stimulated
  8. Extensibility
    The ability to be stretched or extended
  9. Elasticity
    The ability of a muscle fiber to recoil and resume its normal resting length after being stretched or contracted
  10. Skeletal Muscle Functions
    • Producing Movement
    • Maintianing Posture
    • Stabilizing Joints
    • Generating Heat
  11. Producing Movement
    The movement of the skeleton
  12. Maintianing Posture
    The ability to make minute changes in positon to maintain normal positioning
  13. Stabilizing Joints
    Muscle tissue and muscle connections surround joints and keep them in position
  14. Generating Heat
    Muscles generate heat as they contract thereby maintaining normal body temp
  15. Skeletal Muscle can be broken down into smaller and smaller functional units
    • Muscle - a bundle of muscle fascicles
    • Fascicle - A bundle of muscle fibers
    • Muscle fiber - the muscle cell
    • Muscle Cell- Contains Myosin and Actin
  16. Skeletal Muscle
  17. Connective Tissue Sheaths
    within the muscle” A sheath of primarily reticular fibers that covers the muscle fiber
  18. Connective Tissue Sheaths
    around the muscle” A sheath of fibrous connective tissue that covers the muscle fascicle
  19. Connective Tissue Sheaths
    outside the muscle” - A sheath of dense irregular connective tissue that covers the whole muscle
  20. Muscle Attachments
    The Origin
    The place of attachment which provides little to no movement
  21. Muscle Attachments
    The Insertion
    The place of attachment which provides the most movement (moveable bone)
  22. Muscle Attachments
    Direct or Fleshy attachments
    The epimysium fuses to the periosteum of a bone or perichondrium of a cartilage
  23. Muscle Attachments
    Indirect attachments
    The connective tissue wrappings of the muscle extend beyond the muscle to form either a rope like tendon or a sheet like aponeurosis
  24. Muscle Fiber
    Cell membrane of the muscle cell
  25. Muscle Fiber
    Cytoplasm of the muscle cell
  26. Muscle Fiber
    Red pigment that stores oxygen in the muscle
  27. Muscle Fiber
    Rod-like fibers that run parallel down the length of the muscle fiber. Hundreds to thousands of myofibrils can be found in one fiber and account for approximately 80% of the cellular volume
  28. Muscle Fiber
  29. Muscle Fiber
  30. Muscle Fiber
  31. What are Myofibrils made of?
    Primarily made up of thick filaments and thin filaments
  32. What are thick filaments composed of?
    Primarily composed of a protein called myosin
  33. Myosin heads
    Globular heads on Myosin (thick) that can attach to actin.
  34. What are thin filaments composed of?
    Primarily composed of actin
  35. Tropomyosin
    A thin strand that wraps around Actin (thin) and blocks the actin binding sites
  36. Troponin
    A three polypeptide complex that regulates the position of tropomyosin relative to the actin binding sites.
  37. Sarcoplasmic reticulum

    An elaborate smooth endoplasmic reticulum that’s primary function is to regulate intercellular levels of calcium
  38. T Tubules
    • A long tube-like structure that are continuous with the sarcolemma
    • Runs in between two sarcoplasmic reticulums.
    • Action of the T Tubule:to initiate the release of calcium from the sarcoplasmic reticulum.
  39. Muscle contraction
    Shortening of the muscle fibers by the activation and movement of actin fibers over myosin fibers causing overlap (Sliding filament theory of contraction)
  40. When does muscle contraction occurs?
    when nerves excite the muscles by secreting a neurotransmitter called acetylcholine (ACH)
  41. What do ACH causes?
    Causes sarcolemma of the muscle fiber to produce an action potential which travels down the T tubule
    Neurons initiate the muscle contraction by secreting a chemical called Acetylcholine (ACH). This causes an action potential to occur on the surface of the Sarcolemma. The action potential then travels down the T-Tubule to activate the secretion of calcium from the Sarcoplasmic Reticulum. The calcium is then able to bind to Troponin which changes configuration. This change in configuration causes Tropomyosin to shift out of position allowing the globular head of Myosin to bind to the active site found on Actin.
  43. Steps in Muscle Contraction
    • Cross Bridge formation
    • The Power stroke
    • Cross Bridge detachment
    • Cocking the myosin head
  44. Cross bridge formation
    This is when the Myosin head is attached to actin
  45. The Power stroke
    The changing of the myosin head configuration from a high energy position (straight) to low energy position (bent) causes movement of the actin fiber
  46. Cross bridge detachment
    This is when a new ATP molecule binds to the Myosin head causing the head to loose its grip on actin
  47. Cocking the myosin head
    Once ATP is bound it is quickly converted to ADP causing the myosin head to go back into its high energy position
  48. Muscle Striations and Muscle Contractions
    A Band
    Dark band where actin and myosin overlap
  49. Muscle Striations and Muscle Contractions
    I Band
    Light band where only actin can be found
  50. Muscle Striations and Muscle Contractions
    H - Zone
    the area where only myosin filaments can be found
  51. Muscle Striations and Muscle Contractions
    Z - Line
    The midline in the I band where actin filaments can connect to each other
  52. Muscle Striations and Muscle Contractions
    M - Line
    The mid-line in the H - Zone where Myosin fibers are anchored
  53. Muscle Contraction
  54. Muscle Contraction