A&P 1 exam 3 (part 1)

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  1. single motor neuron and all of the muscle fibers it innervates
    motor unit
  2. the basic and smallest unit of skeletal muscle contraction
    motor unit
  3. if control is important, you want motor units to be
  4. if control is not important, you want motor units to be ?
  5. motor units depend on?
    what muscle does
  6. low intervation ratio?
    few muscle fibers per motor neuron
  7. high intervation ratio?
    more muscle fibers per motor neuron
  8. is control important in low intervation or high intervation ratio?
    low intervation ratio
  9. high intervation ratios give you
    more power
  10. where are motor units found with low intervation?
    • extrinsic eye muscles
    • muscles that move fingers ( like able to pick up a feather and bowling ball)
  11. example of high innervation?
    moving large parts of body like the leg, thigh, quads or hamstrings)
  12. in high innervation you do not need?
    precise control but minimum amount of power
  13. what does brain control?
    motor units and variation between muscles
  14. responsible for contracting motor units
    role of nervous system
  15. 2 types of muscle contraction
    • isotonic
    • isometric
  16. same force
  17. in isotonic contraction, what happens to the muscle fibers?
    they shorten, which gives them movement
  18. same length
  19. what happens to muscle fibers in isometric contraction?
    muscle fibers do not shorten
  20. moveable force? immoveable force?
    • isotonic contraction
    • isometric contraction
  21. generating a force depending on strength and resistance
  22. what happens when there is a combination of isotonic and isometric contractions?
    elevating and holding
  23. what is the only thing a muscle fiber can do?
  24. when a muscle receives a nervous impulse what happens?
    it twitches
  25. what can only be initiated with a nervous impulse?
    contraction and skeletal muscle
  26. all or none response (invariant)
    twitch response
  27. how does the twitch response length of time vary?
    duration varys from muscle to muscle
  28. different muscles have a different length of ?
  29. shortest twitch response?
    1/100th of a second
  30. longest twitch response?
    1/10th of a second
  31. where is a short twitch response found?
    in eye muscles
  32. where is a long twitch respond found?
    quads, hamstrings
  33. twitch response happens at what level?
    cell level
  34. time it takes when neuron arrives at motor unit to when contraction actually occurs
    laten period
  35. what is a muscle twitch initiated by?
    a nervous impulse, stimulus
  36. minimum stimulus strength
  37. is required stimulus is above this, it will generate twitch response
  38. if required stimulus is below this, it will not generate a twitch response
  39. if you see a twitch, then is was atleast ____ and will always get the same response and amount
  40. do muscle fibers twitch at organ level?
  41. contraction of whole muscles and is variable
    organ level contraction
  42. the force of organ level contraction depends on?
    the number of motor units
  43. min force ?
    1--- 1 motor units
  44. max force organ level contraction?
    all motor units are contracting
  45. in organ level contraction, the CNS determines?
    the number of motor units that will contract
  46. what is variation based on with organ level contraction?
    recruitment of motor units
  47. where does recruitment take place?
    in the CNS
  48. don't change twitch, but use multiple and overlapping twitches to get the job done
    twitch fusion
  49. high enough to arrive again before other twitch relaxes
  50. partial twitch fusion where things partially overlap
  51. complete twitch fusion
    complete tetanus
  52. increase frequency more and stimulus arrive during contraction phase of previous twitch
    incomplete tetanus
  53. during what is there no relaxation because the frequency is high enough
    complete tetanus
  54. this only works for a short period of time
  55. increase duration of contraction by twitch fusion
  56. motor unit stays in ____ until you stop stimulating is or if you run out of energy
  57. twitches get greater and greater
  58. common result of twitch fusion but doesn't always occur
  59. when happens with a higher twitch?
    sarcomeres pull 2 times closer together
  60. during summation, when a twitch hits the point where it levels off, the sarcomere is?
    fully contracted
  61. only works for seconds?
  62. made up of motor units and prolongs partial contraction
  63. tonus helps to
    spread out duration of a single motor unit
  64. what only works for partial contraction
  65. contraction requires?
  66. during contraction ATP must be synthesized as fast as?
    it is used up
  67. problem with ATP during contractions?
    muscle doesn't have enough ATP
  68. transfer PCr to ADP, which then goes to ATP?  this happens during?
    • phosphocreatine
    • ATP resynthesis
  69. muscle fiber types?
    • red
    • white
  70. red fibers rely on?
    oxidation of glucose for energy
  71. have a slow twitch, oxidative and darker in color
    red fiber
  72. have a fast twitch, powerful, glycolytic and lighter in color
    white fibers
  73. white fibers contraction?
    contract quicker, less time to contract
  74. how is the proportion of red vs white fibers determined?
    muscle function and genetics
  75. red vs white fibers use muscle function? when
    whether speed and contraction or durability is more important
  76. red vs white fibers use genetics when?
    individual variation
  77. sprinters have high proportion of what type of fibers?
  78. marathon runners have high proportion of what type of fibers?
Card Set:
A&P 1 exam 3 (part 1)
2014-10-20 19:05:51
anatomy physiology fall 2014 bio 259

General Principles of Muscle Contraction Fall 2014
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