Anatomy Chapter 11 The Muscular System

  1. There are ______ Human skeletal muscles
  2. What are the levels of the fascia?
    • Superficial
    • deep
    • epimysium
    • perimysium
    • endomysium
    • tendons
    • aponeuroses
  3. Epimysium...
    • Covers whole muscle belly
    • blends into connective tissue that separates muscles
  4. Perimysium...
    • a slightly thicker layer of connective tissue
    • surrounds a bundle of cells called a fascicle
  5. Endomysium...
    • A thin layer of areolar tissue surrounding each cell
    • allows room for capillaries and nerve fibers
  6. Where is Deep Fascia found?
    Between adjacent muscles
  7. Where is Superficial Fasscia (Hypodermis) found?
    • Between skin and muscle
    • *contains adipose tissue*
  8. Most skeletal muscles span _____ and are attached to bone in at least two places
  9. When muscles contract the ______ bone, the muscle's insertion moves toward the _______ bone (The muscles origin)
    • moveable
    • immovable
  10. Muscles attach in what two ways?
    • Directly: epimysium of the muscle is fused to the periosteum of a bone
    • Indirectly: connective tissue wrappings extend beyond the muscle as a tendon or aponeurosis
  11. Each muscle is served by one ____, an _____, and one or more ______
    • nerve
    • artery
    • veins
  12. Each skeletal muscle fiber is supplied with a _______ ending that controls _________
    • nerve
    • contraction
  13. __________ require continuous delivery of oxygen and nutrients via arteries
    Contracting fibers
  14. Wastes must be removed via
  15. Describe a muscle fiber
    • A long, cylindrical cell with multiple nuclei just beneath the sarcolemma
    • Fibers are 10 to 100 mm in diameter, and up to hundreds of centimeters long
  16. Each cell is a _________ produced by fusion of embryonic cells
  17. Sarcoplasm has numerous _________ and a unique oxygen-binding protein called ________
    • glycosomes
    • myoglobin
  18. Muscle Fibers contain ______, ______, ___________, and _________
    • organelles
    • myofibrils
    • sarcoplasmic reticulum
    • T tubules
  19. Myofibrils are
    densly packed, rodlike contractile elements
  20. ______ make up most of the muscle volume
  21. The arrangement of myofibrils within a fiber is such that a 
    perfectly aligned repeating series of dark A bands and light I bands is evident
  22. What is the smallest contractile unit of a muscle
  23. A Sarcomere is 
    the region of a myofibril between two successive Z discs
  24. Sarcomeres are composed of 
    Thick and thin myofilaments made up of contractile protein
  25. Thick myofilaments extend...
    the entire length of an A band
  26. Thin myofilaments extend..
    across the I band and partway into the A band
  27. What is a Z-disc?
    a coin-shaped sheet of proteins (connectins) that anchors the thin filaments and connects myofibrils to one another
  28. Thick filaments are composed of the protein ____
  29. Each ___________ has a rodlike tail and two globular heads


    myosin molecule

    two interwoven, heavy polypeptide chains

    Two smaller, light polypeptide chains called cross bridges
  30. Thin filaments are chiefly composed of the protein ____
  31. Each _______ is a helical polymer of globular subunits called G actin
    actin molecute
  32. The subunits of actin molecule contain the active cites to which _______ attach during contraction
    myosin heads
  33. _________ and ________ are regulatory subunits bound to actin
    Tropomyosin and troponin
  34. Sarcoplasmic Reticulum is
    an elaborate, smooth enodplasmic reticulum that mostly runs longitudinally and surrounds each myofibril
  35. Sarcoplasmic Reticulum functions in the regulation of ____________ levels
    intracellular calcium
  36. Elongated tubes called _________ penatrate into the cell's interior at each A band-I band junction
    T Tubules
  37. _________ associate with the paired terminal cisternae to form _____
    • T Tubules 
    • triads
  38. T Tubles are continuous with the ______
  39. T Tubules conduct _____ to the deepest regions of the muscle
  40. The impules conducted by T Tubules signal for the release of ______ from adjacent terminal cisternae
  41. ______ and __________ provide tightly linked signals for muscle conraction
    • T tubules 
    • SR
  42. A double zipper of ___________________ protrudes into the intermembrane space
    integral membrane proteins
  43. T tubule proteins act as __________
    voltage sensors
  44. SR foot proteins are receptors that regulate ____ release from the SR cisternae
  45. At low intracellular Ca2+ concentration:
    • Tropomyosin blocks the binding sites on actin
    • Myosin cross bridges cannot attach to binding sites on actin
    • The relaxed state of the muscle is enforced
  46. At higher intracellular Ca2+ concentrations
    • Additional calcium binds to troponin ( inactive troponin binds two Ca2+)
    • Calcium- activated troponin binds an additional two Ca2+ at a separate regulatory site
  47. Contraction
    refers to the activation of mysoin's cross bridges (force- generating sites)
  48. _______ occurs when the tension generated by the cross bridge exceeds forces opposing shortening
  49. ________ ends when cross bridges become inactive, the tension generated declines, and relaxation is induced
  50. Contraction of ______-- and ___________ is similar
    • mucle fibers (cells)
    • muscles (organs)
  51. Two types of muscle contractions are
    • Isometric contraction
    • Isotonic contraction
  52. An isometric contraction is
    increasing mucle tension (Muscle does not shorten during contraction)
  53. Isotonic contraction is
    decreaseing muscle length (muscle shortens during contraction
  54. A motor unit is a __________ and all the muscle fibers it supplies
    motor neuron 
  55. The number of muscle fibers per motor unit can vary from 
    four to several hundred
  56. Muscles that control fine moevemnts (fingers, eyes) have 
    small motor units
  57. Factors Affecting Muscle Tension
    • Frequency of stimulation
    • Length of fibers
    • Number of fibers contracting
  58. Amount of tension production by muscle fibers depends on 
    number of cross bridges formed
  59. Skeletal muscle contracts most forcefully over 
    a narrow ranges of resting length
  60. What is a twitch?
    Cycle of contraction, relaxation produced by a single stimulus
  61. What is a Treppe?
    Repeated stimulation after relaxation phase has been completed
  62. What is summation?
    Repeated stimulation BEFORE relaxation phase has been completed
  63. Wave summation=
    one twitch is added to another
  64. Incomplete tetanus= 
    muscle never relaxes completely
  65. Complete tetanus=
    relaxation phase is eliminated
  66. What is a Myogram?
    The record of a muscle contraction
  67. What are the 3 periods of a myogram?
    • Latent
    • Contraction
    • Relaxation
  68. Where is internal tension generated?
    inside contracting muscle fibers
  69. Where is external tension generated?
    in extracellular fibers
  70. Muscle tone _______ bones and joints
  71. All the muscle fibers are ______ by one neuron
  72. Precise control of movement is determined by ______ and ______ of motor unit
    • number
    • size
Card Set
Anatomy Chapter 11 The Muscular System
Pp Notes