Lecture 12: Muscle

  1. Epimysium
    • in sk. m
    • CT encapsulates major bv's and nerves
  2. Perimysium
    • in sk. m
    • CT encapsulates small bv's and nerves
  3. Endomysium
    • in sk. m
    • CT encapsulates capillaries & nerve endings
    • NO bv's or nerves
  4. Basal vs. external lamina
    • Basal lamina- for epithelial cells
    • external lamina- other? Schwann, muscles
    • External lamina- between sarcolemma & endomysium
  5. Muscle organization
    Muscle->fasicle (group)->myofiber (cell)->myofibril->myofilaments (thin/thick)
  6. I band
    thick only
  7. A band
    both thick & thin
  8. H band
    thick only
  9. M line
    where thick anchors
  10. Nebulin
    • determines thin filament length
    • part of think filament: actin, tropomyosin, troponin, nebulin
  11. Desmin
    links Z line to organelles and sacrolemma
  12. Titin
    • stretch M to Z "tit"ens
    • prevet overextetion during relaxation
  13. Strength of muscle contraction determined by:
    • 1.size of motor unit
    • 2. # motor units activated
    • 3. # myofibrils in each muscle fiber (inc byt exercise/hypertrophy)
  14. Myotendinous junctions
    Very long I bands interact will collegen fibrils of tendon
  15. Golgi Tendon Organ
    pinches sensory nerve endings and provides energy of how much force muscle is producing
  16. muscle spindle
    • intrafusal muscle fiber- encapsulated in fluid filled capsule
    • 1. nuclear chain & nuclear bag 2. annulospiral ending: provides info on RATE of extenision; flower spray: EXTENT
    • extrafusal- outside spindle
  17. dystrophin
    elastic linkage between peripheral actin and dystroglycan, which bind to external lamina
  18. Nemaline Myopathies
    thin filament defect
  19. Desmin-related Myopathies (DRM)
    defect in desmin
  20. Amylotrophic Lateral Sclerosis
    Loss of upper and lower motor neuron
  21. Progressive Muscular Atrophy (PMA)
    Loss of lower motor neurons
  22. Multiple sclerosis (MS)
    Loss of upper motor neurons
  23. Myasthenia Gravis
    Autoimmune, disrupts ACh signaling at NMJ
  24. Mitochondrial Myopathies
    muscle wkness, exercise intolerance
  25. MD: Duchenne MD, Myotonic MD
    • progressive wkness, muscle fiber necrosis
    • Duchenne MD- defects in dystrophin gene, common early onset
    • Myotonic MD- slow relaxation, late onset MD
  26. Pericardium
    2 layers mesothelium: parietal, visceral
  27. Endocardium
    layer of enothelial & subendothelial (sm. m, collegen, fibroblast) cells
  28. Intercalated disks
    • link sarcomeres
    • transverse, longitud
  29. fascia adherens
    • thin filaments insert into fascia adherens
    • like "a Z line"
  30. Desmosomes
    • link intermedaite fil
    • tranverse and long
  31. Gap junction
    • electrical signals portals
    • ONLY long
  32. ANP
    • lowers bp by inhibiting renal Na reabsorption & secretion of vasocontrictors.
    • directly promotes relaxation of sm m
Card Set
Lecture 12: Muscle
skeletal, cardia, smooth