Human Physiology 12

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NursyDaisy
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100783
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Human Physiology 12
Updated:
2011-10-12 00:17:45
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Human Physiology
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Muscles
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  1. Most skeletal muscles cross one or more joints to bring about movements in those joints. Which attach of a muscle usually remains stationary when a muscle contracts?
    the origin
  2. Most skeletal muscles cross one or more joints to bring about movements in those joints. Which attach of a muscle usually moves when a muscle contracts?
    the insertion
  3. What portion of a whole muscle produces the force?
    the belly
  4. What is a muscle producing a particular movement called?
    agonist
  5. What is a muscle that assists the prime mover in its action?
    Synergist (examples: Triceps & anconeus)
  6. What is a muscle whose actions oppose those of the prime mover?
    antagonist
  7. Because of the tissue composition of an individual skeletal muscle what level of organization is a muscle such as the biceps brachii or pectoralis major classified within?
    An organ
  8. What is the study of muscle?
    Myology
  9. List the four characteristics of muscle tissue.
    • excitability
    • contractility
    • elasticity
    • extensibility
  10. In some situations, as when you lay an object on a table, a muscle is actually getting longer while doing what you want. One of the characteristics of muscle that most authors list is contractility. Yet a muscle allowing you to extend your elbow in a controlled fashion is not getting shorter. What is it
    doing?
    Producing force
  11. What is another term for skeletal muscle cell?
    Muscle fibers
  12. What are five functions of muscle tissue. Be aware of how smooth and cardiac muscle as well as skeletal muscle might be involved in these functions.
    • body movement
    • maintenance of posture
    • temperature regulation
    • storage and movement of materials
    • support
  13. What are cordlike structures that attach muscle to bone, skin, or other structures?
    tendons
  14. What are sheets of tissue that connect muscle to bone, skin, or other structures?
    Aponeuroses
  15. What is another term for the plasma membrane of a muscle fiber?
    sarcolemma
  16. What histological term refers to the stripes seen in cardiac and skeletal muscle fibers?
    striations
  17. What is histological term for the functional connection between a muscle fiber and a motor neuron?
    the neuromuscular junction
  18. What is the specialized region of the sarcolemma at the neuromuscular junction?
    motor end plate
  19. What are all of the muscle fibers innervated by a single motor neuron?
    a motor unit
  20. What is the functional unit of a whole skeletal muscle?
    the motor unit
  21. How are contractions of varying strengths produced within a skeletal muscle?
    by recruiting varying numbers of motor units
  22. What is the number of muscle fibers innervated by a single motor neuron?
    the innervation ratio
  23. What is the relative innervation ratio for muscles involved in fine skeletal movements?
    low (1:10 is the low end)
  24. What is the relative innervation ratio for muscles involved in gross skeletal movements?
    high (1:2000 is the high end)
  25. What is the process of activating motor units?
    recruitment
  26. What are the longitudinal, parallel subunits within a muscle cell?
    myofibrils
  27. What are the long, thin strands of contractile proteins within a muscle fiber?
    myofilaments
  28. What are the two types of myofilaments within a muscle fiber?
    thick and thin filaments
  29. What protein makes up the thick filaments of a muscle fiber?
    myosin
  30. What protein makes up the thin filaments of a muscle fiber?
    actin
  31. What is the functional unit of a muscle fiber?
    a sarcomere
  32. What structure are thin filaments attached to proximally and distally within a sarcomere?
    the Z-lines
  33. What structure makes up the proximal and distal borders of a sarcomere?
    the Z-lines
  34. What structure attaches a thick filament to the Z-line?
    a titin filament
  35. Shortening of a sarcomere occurs due to what action?
    sliding of the myofilaments over one another
  36. What part of myosin changes configuration to bring about contraction?
    the cross bridge (myosin head)
  37. What part of a sarcomere functions to split ATP to ADP and Pi and thus release energy for contractions? What is a second name for this part?
    the myosin head acts as myosin ATPase
  38. What term describes the change in configuration of a cross bridge that is attached to actin?
    power stroke
  39. What two chemicals are attached to a cross bridge that is cocked but not attached to actin?
    ADP + Pi
  40. What chemical must be released from a cross bridge in order for the power stroke to occur?
    Pi
  41. What chemical is released from the cross bridge after the power stroke?
    ADP
  42. What chemical must attach to the cross bridge in order for it to release from actin after the power stroke?
    ATP
  43. What is the immediate source of energy for muscle contractions?
    ATP
  44. What is the result of the hydrolysis of ATP to ADP and Pi after the power stroke?
    the energy is used to cock the cross bridge
  45. What molecule covers the active sites on actin when a muscle is relaxed?
    tropomyosin
  46. What molecule is attached to tropomyosin to allow its regulation?
    troponin
  47. What ion binds to troponin to change it configuration?
    Ca++
  48. What organelle stores calcium within a muscle fiber?
    the sarcoplasmic reticulum
  49. What neurotransmitter occurs at the neuromuscular junction?
    acetylcholine
  50. What structures open to the extracellular environment outside of a muscle fiber and conduct action potentials through the cell?
    transverse tubules
  51. Action potentials within a muscle fiber are not graded. What is this effect called?
    the all-or-none law
  52. What type of structure opens within the t-tubules in response to depolarization?
    voltage-gated Ca2+ channels
  53. What type of mechanism regulates the release of Ca2+ from the sarcoplasmic reticulum?
    Ca2+-induced Ca2+ release mechanism
  54. What structures remove Ca2+ from the sarcoplasm once a muscle fiber is no longer depolarizing?
    Ca2+-ATPase pumps
  55. What type of contraction occurs as a muscle actually gets shorter when producing force?
    isotonic or concentric
  56. What type of contraction occurs when a muscle does not change its length as it produces force?
    isometric
  57. What type of contraction occurs when a muscle is elongated as it produces force?
    eccentric or lengthening
  58. What is the general relationship between the length of a muscle and the tension it is able to produce?
    There is an ideal length (2-2.25 m) at which the fiber produces maximum force. Any increase or decrease in this length lessens the force produced.
  59. Skeletal muscles at rest obtain most of their energy from what?
    aerobic respiration of fatty acids
  60. What is the main source of energy for skeletal muscle during heavy exercise?
    muscle glycogen
  61. Exercise increases the what carrier molecule in the plasma membranes of muscle fibers?
    GLUT 4 (the carrier protein for glucose)
  62. What source of energy usually makes up the largest percentage of that used by a muscle?
    free fatty acids from the plasma
  63. What is the maximum rate of oxygen consumption by the body?
    VO2max (maximal oxygen uptake or aerobic capacity)
  64. What units is V-O-2 max measured in?
    ml of oxygen per minute per kilogram of body weight
  65. What is the general range of V-O-2 max overall?
    12 ml/min/kg in older, sedentary people to 84 ml/min/kg in young, elite, male athletes
  66. What is the percentage of the maximal oxygen uptake at which a significant rise in blood lactate
    levels occurs?
    lactate threshold
  67. Why does a person continue to breathe heavily after exercise?
    to repay the oxygen debt
  68. What is the cause of oxygen debt?
    the use of oxygen stored in hemoglobin and myoglobin
  69. What substance is used to make ATP when ATP is used faster than it can be produced through
    cellular respiration?
    creatine-phosphate (phosphocreatine)
  70. What are the two categories of skeletal muscle fibers based on contraction time?
    slow-titch (type I) and fast-twitch (type II)
  71. Within muscles, what is the red pigment, similar to hemoglobin, that stores oxygen?
    myoglobin
  72. Based on metabolism, what other term may be used for slow-titch muscle fibers?
    slow-oxidative
  73. Based on the amount of myoglobin, what is another term for slow-twitch muscle fibers?
    red fibers
  74. Based on the amount of myoglobin, what is another term for fast-twitch fibers?
    white fibers
  75. Based on metabolism, what are the two types of fast-twitch fibers?
    fast oxidative (type IIA) and fast glycolytic (type IIX)
  76. What is exercised-induced reduction in the ability of a muscle to generate force?
    muscle fatigue
  77. What appears to be the cause of muscle fatigue during maximal contractions?
    an accumulation of K+ outside of the cells
  78. What are the two major components of muscle fatigue?
    peripheral (within muscles) and central (in the CNS)
  79. What is the general adaptation shown in muscles trained for endurance?
    an increase in aerobic capacity through such changes as more mitochondria and capillaries
  80. What is the general adaptation of muscles trained with high-intensity exercise?
    hypertrophy from an increase in cross-sectional area of fibers and an increase in the number of fibers
  81. How can damaged muscle fibers be replaced?
    through the conversion of satellite cells into muscle fibers
  82. What sensor responds to the tension put on tendons?
    Golgi tendon organ
  83. What sensor responds to changes in muscle length?
    muscle spindle apparatus
  84. What is a response to sensory input that does not depend on the activation of upper motor neurons?
    a reflex
  85. What is the neural pathway of a reflex?
    a reflex arc
  86. What type of reflex arc involves a single synapse within the CNS?
    a monosynaptic reflex
  87. What reflex occurs in all muscles in response to a rapid change in their length?
    the stretch reflex
  88. What type of reflex has two synapses within the CNS?
    a disynaptic reflex
  89. What is the effect of feedback from the Golgi tendon organs?
    inhibition resulting in relaxation
  90. Stretch reflexes involve dual innervation. The agonist is excited. The antagonist is inhibited. What is this dual innervation called?
    reciprocal innervation
  91. What is reciprocal innervation of both the side of the body sensing a reflex stimulus and the contralateral side?
    double reciprocal innervation
  92. What type of double reciprocal innervation occurs when a painful stimulus occurs on the sole of one
    foot?
    a crossed-extensor reflex

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