Anatomy 9-11

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Anatomy 9-11
2013-06-21 17:34:29

chapters 9 through 11
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  1. What is a muscle fibers plasma membrane?
  2. What does myoglobin store?
    O2 (oxygen)
  3. Glyosomes are granules of?
  4. Function of the SR?
    Store Calcium (Ca2+)
  5. What is continuous with sarcolemma and closely associated with SR?
    T tubule
  6. Thin filament is made of
    • Actin
    • Tropomyosin
    • Troponin
  7. Thick filament is made of?
    • Myosin
    • Titin
  8. A band:
    • Dark band
    • Thick and Thin filaments
  9. I band:
    • Light band
    • no thick filament
  10. Sarcomere
    • Functional unit of myofibril and skeletal muscle.
    • From of Z disc to the next.
  11. Neuromuscular Junction
    Interaction between motor neuron and skeletal muscle cell.
  12. Neurotransmitter released at neuromuscular junction:
    • ACh (acytocholine)
    • Removed by acetylcholinesterase
  13. AP generation on sarcolemma:
    • AP at axon terminal
    • CA2+ influx
    • ACh exocytosis
    • ACh binds to receptor
    • Chemical-gated Na+ channels open
    • Na+ influx
    • Depolarization
    • Voltage-gated Na+ channels open
    • Na+ influx
    • threshold potential
    • positive feedback
    • depolarized to AP
    • voltage-gated K+ channels open
    • k+efflux
    • repolarization
  14. Cross bridge cycle
    • Ap along T tublue opens ca2+ channels in SR
    • Ca2+ enters cytosol and binds to troponin
    • Tropomyosin shifts position to expose binding sites
    • Myosin head binds to actin
    • Power stroke of myosin head causes sliding
  15. What is the function of ATP in the cross bridge cycle?
    • ATP allows myosin to detach from actin (rigor mortis w/o ATP)
    • Hydrolysis of ATP into ADP and Pi provides energy: low state to high state.
  16. Does cross bridge cycle stop immediate after AP disappears?
    Not until Ca2+ return to SR
  17. What is shortened during isotonic contraction?
  18. Muscle sheath:
    Dense fibrous connective tissue
  19. Epimysium
    Enclose the whole muscle
  20. Perimysium
    enclose each fascicle
  21. Endomysium
    Enclose each muscle fiber
  22. Motor unit
    a neuron and all the muscle cells it controls
  23. Muscle fatigue
    when a muscle is stimulated bu can no longer contract due to ionic imbalance and SR damage.
  24. Muscle tone
    the continuous partial contraction state of muscle
  25. Isometric
    Tension develops but muscle does not change length
  26. Isotonic
    Muscle length changes during a contraction
  27. Latent period
    brief period without measurable muscle tension.
  28. Contraction
    The period with active sliding of myosin and actin fibers
  29. Relaxation
    When the cross bridge cycle stops
  30. Wave summation
    • Low frequency
    • before relaxation.
  31. Fused tetanus
    • High frequency
    • smooth sustained contraction
  32. How does the muscle respond to increased strength of stimulus?
    Recruitment of motor units
  33. How is ATP generated for muscle?
    • CP pathway which donates P to ADP
    • Anerobic glycolysis which produces lactic acid
    • aerobic pathway (cellular respiration; produces most ATP)
    • 60% of energy from ATP is wasted as heat.
  34. What affects contraction force in a given muscle?
    • Size of muscle fiber
    • recruitment
    • frequency of stimuli
    • optimal length
  35. Slow Fibers
    • red
    • aerobic pathway
    • slow fatigue
  36. Fast fibers
    • white
    • anaerobic glycolysis
    • fast fatigue
  37. A muscle usually has....
    mixed types
  38. Fibers in one motor unit are...
    the same.
  39. What makes a given muscle contract fast?
    • Less load
    • recruit MORE muscle fibers
    • MORE fast fibers
  40. What makes a given muscle contract for longer duration?
    • Less load
    • recruit more muscle fibers
    • more slow fibers
  41. Why are some muscles more powerful than others?
    They contain more muscle fibers.
  42. Smooth muscle
    • No T tubule
    • Poor SR
    • Ca2+ mainly from outside
    • Use less ATP
    • Stimulation through varcosities
  43. Origin
    fixed or immovable point of attachment
  44. insertion
    attachment on the moveable bone
  45. Prime mover/Agonist
    primarily responsible for producing a specific movement
  46. Antagonist
    Oppose or reverse the action of another muscle
  47. Synergist
    aids another muscle by promoting the same movement
  48. fixator
    stabilizes the origin of another muscle
  49. Adduction
    pectoralis major - latissimus dorsi
  50. abduction
  51. flexion
    • biceps brachii
    • brachialis
  52. extension
    triceps brachii
  53. dorsiflexion
    tibialis anterior
  54. plantar flexion
    • gastrocnemius
    • soleus
  55. Astrocyte
    transport nutrients from capillaries to neurons
  56. Microglia
  57. ependyma
    • ciliated
    • circulate fluid
  58. oligodendrocyte
    form myelin sheath
  59. schwann cell
    form myeline sheath
  60. satellite cells
    cover neuron cell body
  61. Structure of a neuron
    • Cell body
    • Axon
    • Myelin sheath
  62. Sensory neuron
    • Afferent fibers
    • Carry signal from sensory receptor to CNS
  63. Motor neuron
    • Efferent fibers
    • carry signal from CNS to effector (muscle and gland)
  64. Interneuron
    • Most abundant neuron
    • Mostly in CNS
    • Conduct between motor and sensory neurons
  65. RMP
    • -70mV
    • plasma membrane polarized
  66. depolarization
    less negative than RMP
  67. hyperpolarization
    more negative than RMP
  68. Effect of inreasing extracellular k+ on RMP
    RMP becomes less negative.
  69. Graded potential
    • variable magnitude
    • chemical-gated channels
    • depolarization or hyperpolarization
    • dendrite and cell body
  70. Action potential
    • all-or-none
    • voltage-gated channels
    • depolarization
    • axon hillock (initiate AP) and axon
  71. Why can myelin sheath electrically insulate axon?
    membrane lacks ion channels.
  72. Threshold potential
    Initiate positive feedack: open voltage-gated Na+ channels
  73. What ion is responsible for the depolarization phase and repolarization phase of AP?
    • Depolarization: Voltage-gated Na+ changels open, Na+ moves in
    • Repolarization: voltage-gated K+ channels open, K+ moves out
  74. How does neuron respond when a stimulus is given in absolute refractory period?
    • Na+ channels inactive
    • Produce no AP
  75. Relative refractory period?
    • Threshold is elevated
    • requires stronger stimulus to generate AP
  76. How is the intensity of stimuli to a neuron coded?
    high stimulus > high AP frequency
  77. Myelin sheath
    insulate axon to speed up propagation
  78. Node of Ranvier
    • exposed region on axon
    • boost AP
  79. AP propagates in one direction due to....
    absolute refractory period.
  80. Distance between Nodes of Ranvier> ^ AP propagation speed?
    No. distance too long so AP cannot propagate
  81. What is the fate of neurotransmitters in the synaptic cleft?
    • Reuptake by astrocytes or axon terminals
    • degraded by enzymes in synaptic cleft
    • diffuse away from synaptic cleft
  82. How does the neurotransmitter open ion channels in the postsynaptic membrane?
    • Direction: receptor is ion channel
    • Indirectily: open channels through a 2nd messenger.
  83. How do signals from one neuron pass to another?
    • Through synapse
    • Axon terminal
    • Synaptic cleft
    • postsynaptic membrane
  84. So these signals always lead to the generation of AP in the post synaptic cleft?