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Flashcards

FOM sep 23

Shylla T English 99 cards

Cards in this deck (99)

  1. 1epimysiumouter fibrous layer of the WHOLE muscle; what we often call the “Deep Fascia
  2. 2Muscles contract bythick myosin filament pulling the thin actin filaments to the center of the sarcomere
  3. 3The Motor Unit refers toone alpha motor neuron and ALL of the muscle fibers that are innervated by it.
  4. 4Muscle spindlescollect information on stretch and contraction timing and report this to the spinal cord, which forwards the information back to the cortex and cerebellum.
  5. 5myscles are activated by and need to be contractednerve thru bouton
  6. 6bwteeen the bouton and sacrolemmasynaptic cleft
  7. 7t tubules carrysignal from outside to inside to the middle
  8. 8muscle spindlemain job is to send signals to brain/cns to let it know that the muscle is streching or contracting (feedback)
  9. 9..
  10. 10Functional demands of bonePROVIDE RIGID LEVER ARMS FOR MOVEMENT
    BE ADAPTABLE
  11. 11PROVIDE RIGID LEVER ARMS FOR MOVEMENResist compressive, tensile, shear, bending and torsional forces
    Be stiff but not overly brittle
    Protect of vital soft tissue
    Provide locus of hemopoesis and immune differentiation in marrow space, cancellous bone (changes with development
  12. 12the soluions for these damandsOne solution to these demands is the material.
    In this case the material is a COMPOSITE MATERIAL, with cells secreting Type I collagen fibers that become imbedded with mineral this case Hydroxyapatite.
  13. 13BE ADAPTABLEACCOMMODATE GROWTH
    REPAIR ITSELF
    PROVIDE READILY-ACCESSIBLE MINERAL RESERVOIR (calcium, phosphorus)
  14. 14ACCOMMODATE GROWTHExpand
    Adapt to local physical demands throughout ontogeny
  15. 15Remodeling createsHaversian systems
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  21. 21REMODELINGRemoves bone mass.
    Liberates sequestered calcium
  22. 22remodeling is done byosteoclast who break down the bone to release ca into blood since bone is being used less
  23. 23mechanical stressstimulates bone or bone remodeling
    so less m stress means bone is being used less which means its going to be broken down
    area of more stress will cause remodeling to make stronger bone
  24. 24bone remodeling happens because of 2 reasonshormonal controls--less ca2 in blood
    response to mechanical stress
  25. 25FACTORS DRIVING INCREASED RESORPTIONDecreased estrogen
    Increased bone sensitivity to PTH
    Increased PTH levels
    Lack of loading
  26. 26FACTORS INHIBITING BONE FORMATIONDecreased kidney production of 1,25(OH)2D3 vitamin d
    Decreased calcium absorption in gut
  27. 27STAGES OF REMODELINGACTIVATION
    Resorption
    Coupling
    Formation
    Mineralization
  28. 28ACTIVATIONActivated osteoblast lining cells produce collagenase
    Which digests osteoid on bone surface, exposing mineralized matrix.
    minerals attract osteoclasts,
  29. 29Resorptionosteoclast produce acid and break down mineral
    Bone mineral is dissolved
    Organic matrix phagocytized.
  30. 30Coupling1-2 week gap between osteoclast resorbing & bone formation onset.
    Osteoblasts recruited to site.
  31. 31FormationOsteoblasts line exposed bone surface
    Secrete osteoid.
    Duration about 3 months.
  32. 32MineralizationCommences 10-15 days after onset of formation.
    3-6 months after formation completion for complete mineralization.
  33. 33Osteoclast inhibitorsbisphosphonates
  34. 34Why exercise is importantLack mechanical stimulation = increased osteoclastic activity, loss of osteoblastic activity
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  38. 38WHAT DOES REMODELING ACCOMPLISH?ACCOMMODATES GROWTH
    REPAIR ITSELF-fracture healing
    PROVIDE READILY-ACCESSIBLE MINERAL RESERVOIR (calcium, phosphorus)
  39. 39ACCOMMODATES GROWTHExpand
    Adapt to local physical demands throughout ontogeny
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  42. 42Osteopenialow overall bone mass and micro-architectural disruption;
  43. 43Osteoporosislow overall bone mass and micro-architectural disruption with accompanying structural deficiency
  44. 44Osteomalaciapoorly mineralized bone; collagen normal.
    Rickets: juvenile type of osteomalacia
  45. 45Osteoporosis is a more severe form of osteopenia Low overall bone mass accompanying structural deficiency.
  46. 46Osteoporosis is caused bymismatch between bone resorption and bone formation
    Loss of bone material can cause cracks to propagate and cause fracture or failure
  47. 47IMPORTANCE OF EXTRACELLULAR MATRIX (ground substance)Collagen provides tensile strength.
    Secreted by osteoblasts.
    Bone mineral provides compressive strength. Crystalizes around collage fibers.
    Both are non-cellular.
    Healing however, needs to deal with both. And cells to drive it.
  48. 48REMODELING DRIVES ARCHITECTURE, HEALS BONE.Architecture is shaped by use. If you don’t use it you lose it.
  49. 49Special attributes of BONE:Loss is ultimately gain: The story of osteoclasts and why bone resorption is good.
    Loving the arteries: Vascularity drives bone remodeling and complete healing
  50. 50..
  51. 51BONE FAILURE -- FRACTURE great force causes failure which causes fractureWhere and how bone fractures
    depends on shape of bone,
    magnitude of force,
    location of loading and condition of bone
  52. 52SHAPETibial fracture typically occurs at narrowest part, distal diaphysis
  53. 53MAGNITUDEFracture from high compressive impact typically result in multiple fracture planes
  54. 54LOCATIONDistal radius (Colle’s fracture); Clavicle in juveniles.
  55. 55SPIRAL FRACTUREFAILURE IN TORSION
    Typical high force: auto accident, skiing.
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  58. 58What is the underlying cause of this fracture?great force
  59. 59Avulsion fracturefailure in tension from traction
  60. 60If there is a stable fracture site vascular continuity can be established between broken fragmentsmesenchymal repair blastema will differentiate directly into trabecular bo
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  66. 66TENDONS functionsTendons carry tensile forces from muscle to bone
    They carry compressive forces when wrapped around bone like a pulley
  67. 67tendons blood supplyVessels in perimysium (covering of tendon)
    Periosteal insertion
    surrounding tissues
  68. 68ligament anatomySimilar to tendon in hierarchical structure
    Collagen fibrils are slightly less in volume fraction and organization than tendon
    Higher percentage of proteoglycan matrix than tendon
  69. 69ligaments blood supplyMicrovascularity from insertion sites
    Nutrition for cell population; necessary for matrix synthesis and repair
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  73. 73Grades of strainGrade I
    Grade II
    Grade III
  74. 74Grade Iwithin physiological loading, small number of collagen fibrils fail
  75. 75Grade IIsignificant failure, joint laxity, severe pain
  76. 76Grade IIIcomplete failure
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  79. 79cell type of cartilagechondrocytes
    Tissue fluid (proteglycans and glycoproteins)
  80. 80collagen of crtilagetype II collagen
  81. 81In cartilage the resistance to compression is provided by:water binding to cations
    Repulsion of proteoglycan side units
  82. 82stiffness of cartilage due torepulsion
    turgidity
  83. 83RepulsionStrong negative charge due to sulfate/carboxyl disassociation creates strong repulsive forces on monomers.
  84. 84TurgidityCation attraction to negatively charged monomers causes significant OSMOTIC PRESSURE “water-loading
  85. 85growing cartilage is calledgrowth plate cartilage
  86. 86Articular CartilageNo PERICHONDRIUM
    4 regions in articular cartilage (from joint space ------>bone
  87. 87Synovial Jointshigh load with large range of motion
  88. 88cartilage vascular supplyAnti-vascular
  89. 89..
  90. 90Movement is vital in vivo and in vitro forregeneration of cartilaginous tissue
  91. 91AC initially stiff under loading. With increased duration of loadingviscous flow increases deformation and relieves stress on the water
  92. 92Lubricationbinding of cartilage proteoglycans + water
  93. 93Synovial fluidplasma filtrate (electrolytes + small molecules; fewer proteins).
  94. 94Synovial membraneMacrophage-like cells to phagocytize debris
    Cell secreting synovial proteins --
    create viscosity
    -Hyaluronic acid
    -Lubricin
  95. 95Immobilized tendons/ligaments show considerabledegeneration in mechanical properties
  96. 96Mechanisms of lubricationBoundary lubrication (NON-MOVING JOINT)
    Sliding hydrodynamic lubrication (MOVING)
    Squeeze film hydrodynamic lubrication (MOVEMENT & IMPACT LOADING):
  97. 97Boundary lubrication (NON-MOVING JOINT)fluid clings by chemical attraction of lubricin to cartilage surface; close joint approximation.
  98. 98Sliding hydrodynamic lubrication (MOVING)synovial fluid sucked into space.
  99. 99Squeeze film hydrodynamic lubrication (MOVEMENT & IMPACT LOADING):fluid forced out into joint space under load, sucked back when unloaded.

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Flashcards on FOM sep 23, created by Shylla T on 22/09/2019.
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Shylla T
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