Muscle and Bone

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Muscle and Bone
2011-04-20 22:17:03

Muslce, Bone, Skin
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  1. 3 kinds of muscle
    • skeletal muscle
    • cardiac muscle
    • smooth muscle
  2. what is skeletal muscle? what does it connect?
    voluntary muscle tissue

    connects one bone to another via tendon
  3. tendon v. ligament
    tendon = muscle to bone

    ligament = bone to bone
  4. agonist and antagonist
    agonist = muslce repsonsible for movement (contracts)

    antagonist = second muscle (stretches)
  5. when antagonist contracts, in what direction does the muscle move?
    opposite direction as to when it was move when the agonist was contracted
  6. synergistice muscle
    assists agonist by stabilizing the origin bone
  7. Skeletal muscle can squeeze blood and lymph vessels, what advantages does this have?
    aids circulation
  8. muscle is like what kind of machine?

    muscle = leverage to apply force to the bone to move
  9. Is greater or lesser force required to move the bone?
  10. contraction of skeletal muscle - releases energy?
    yes, heat!
  11. what is shivering?
    rapid contraction of skeletal muscle to warm the body
  12. skeletal muscle contraction: sacromere
    composed of thick and thin filaments
  13. sacromere lumen is filled with
    Ca2+ ions

    mitochondria and nuceli
  14. does sacromere have a single or many nuclei?
    many -

    only type of muscle like this
  15. thick and thin filament - actin and myosin
  16. thick = myosin
    thin = actin
  17. contraction involves
    5 stage cycle -

    actin and myosin work together to.....
  18. 1st stage in contraction
    preventing myosin head from bonding-

    tropomyosin covers the active site on actin
  19. why would we not want the myosin head to bind?
    head has high energy position with P and ADP attached
  20. 2nd stage in contraction
    exposing the active site

    troponin pulls the tropomyosin back
  21. 3rd stage in contraction
    myosin head expels a P and ADP (low energy position)
  22. what is this 3rd stage called (when myosin head expels a P and ADP)?
    power stroke

    it causes shortening of the sacromere and the muscle contraction
  23. 4th stage of contraction
    ATP reaches to myosin head from active site
  24. 5th stage of contraction
    ATP splits into P and ADP causing myosin head to cock in high-energy position
  25. overall scheme of contraction
    tropomyosin covers active site and has troponin attached

    when Ca2+ bind to troponin, it changes conformation and moves the tropomyosin

    mvmt. opens myosin binding sites on the actin

    when they bind the move (contract)
  26. How is the muscle contraction initiated?
    action potential

    neron attaches to muscle cell and releases neurotransmitter into synapse
  27. what neurotransmitter is released into begin muscle contraction?
  28. how does the action potential reach deep into the muscle?
  29. stimulated T-tubules spread action potentially rapidly to
    sacroplasmic reticulum
  30. what does an activated sacroplasmic reticulum do
    becomes permeable to Ca2+ ions

    calcium begins 5-stage cycle
  31. what happens to Ca2+ after contraction?
    it is actively pumped back to sacroplasmic reticulum
  32. in contraction what sections reduce in size and which stay the same?
    H and I get smaller

    A band doesn't change
  33. k
  34. does skeletal muscle contract all at once?
    no, single neuron innervates each muscle fiber

    they contract independently of each other
  35. skeletal muscle types
    1. slow oxidative muscle

    2. fast oxidative muscle

    3. fast glycolytic fibers
  36. slow-twitch: color, rate to split ATP
    red - large amounts of myoglobin

    larger mitochondria

    split ATP at a slower rate
  37. slow to split ATP means....
    • slow to fatigue
    • slow contraction velocity
  38. fast-twitch: color? rate to split ATP

    split ATP at high rate
  39. split ATP at fast rate
    fast contraction

    resistant to fatigue
  40. fast-glycolytic color and rate of contraction
    white (b/c of low myoglobin content)

    • contract very rapidly
    • contain large amounts of glycogen
  41. what does myoglobin do?
    stores O2 inside muscle cell
  42. do muscle cells undergo mitosis?

    instead, change over time when exposed to repetitive contraction
  43. cardiac muscle: striate? nuclei, mitochondria? voluntary?

    contains only 1 nucleus

    much more mitochondria - stronger

  44. how are action potentials spread in a cardiac muscle?
    gap junctions
  45. smooth muscle: voluntary? nuclei?
    involuntary - innervated by ANS

    single nucleus
  46. does smooth muscle contain thick and thin filaments if it has only one nucleus?
    yes, but not organized into sacromeres
  47. intermediate filaments and dense bodies in smooth muscle: picture
  48. 2 types
    single unit and multi unit
  49. single unit
    cells connected by gap junctions spreading action potential from a single neuron
  50. single unit: do cells contract separately? where are they found?
    no contracts as a whole

    intestines, arteries, veins, stomach, uterus, urinary bladder
  51. multi unit
    each unit fiber is directly attached to a neuron

    fibers contract independently
  52. is bone living tissue?
  53. 3 types of cells are:
    what are they surrounded by?
    surrounded by extensive matrix

    • 1. osteoblasts
    • 2. osteocytes
    • 3. osteoclasts
  54. osteoblasts
    secrete collagen and organic compounds that form bone

    differentiate into osteocytes
  55. do osteoblasts undergo mitosis?
  56. osteocytes
    exchange nutrients and waste with blood
  57. do osteocytes undergo mitosis?
  58. osteoclasts
    • reabsorb bone matrix,
    • releasing materials back into blood
  59. where do osteoclasts develop from
    white blood cells: monocytes