1. Striated muscle
    Skeletal muscle and cardiac muscle
  2. Unstriated muscle
    Smooth muscle
  3. Voluntary muscle
    Skeletal muscle
  4. Involuntary muscle
    Cardiac and smooth
  5. 4 Properties of muscle tissue
    • Contractility (ability to shorten)
    • Excitablility (capacity to recieve/respond to stimuli)
    • Extensibility (ability to stretch)
    • Elasticity (ability to return to original shape after contraction)
  6. 4 Functions of Muscle Tissue
    • Production of movement
    • Maintaining posture
    • Stabilizing joints
    • Generating heat
  7. Epimysium
    Connective tissue surrounding muscle
  8. Perimysium
    Connective tissue surrounding fascile
  9. Endomysium
    Connective tissue-surrounding fiber
  10. Fascicles
    Muscle bundles made up of muscle fibers
  11. Myofibrils
    A part of the muscle fiber that has sequences of sacromeres.
  12. Sarcomere
    • Functional (contractile) unit of muscle, region between z-lines.
    • Z-line to z-line, the section of muscle that includes M line, A band, and I band.  These are lined up on myofibrils that then make up muscle fibers, fascicles (muscle bundles), and muscle.
  13. 3 Myofibril proteins types
    • Contractile: generate force during contraction Actin, Myosin
    • Regulatory: initiate and terminate contraction; Troponin, Tropomyosin
    • Structural: maintain alignment, elastic & extensible; Titan, myomesin, dystrophin
  14. 3 types of muslce fibers
    • Slow oxidative (type I)
    • Fast Oxidative-Glycolytic (type II-A)
    • Fast Glycolytic (Type II-B)
  15. Z line
    Anchors thin filaments (actin & nebulin)
  16. M line
    Contains myomyesin (binds to Titan & stablize thick filaments)
  17. I band
    Composed of thin filaments
  18. A band
    Composed of thick & thin myofilaments. H zone - only thick filaments, M line - contains Myomyesin (binds to Titan & stabilize thick filaments). Titan - anchors thick filaments to Z and M line
  19. H band
    Only thick filaments
  20. Titan
    Anchors thick filaments to Z and M lines
  21. Tropomyosin and Troponin
    Actin looks like a double stranded string of pearls.  Tropomyosin wraps along this string and effectivley covers the actin binding sites.  Troponin sits along this line with binding sits for Ca+.  When Ca+ is bond, it flexes, moving the Tropomyosin off the binding sites, so that the myosin can bind to the actin.
  22. Transverse tubules
    run perpendicular along the myofibrils and bring the action potential down.  Sarcoplasmic reticulum is where the Ca+ is stored and allows for a quick release.  Lateral sacs "unplug" the calcium stores for a quick response, then pump is back out when it is no longer needed...
  23. Sarcoplasmic reticulum
    2 Terminal cisternae + T tubule = Triad. Cisternae - have Calsequestrin - sequesters Ca+
  24. Skeletal muscle ->
    Myofiber (muscle cell/myocyte - multinucleated) -> Myofibril -> sarcomere -> myofilament
  25. Myofilaments:
    • Thick: cmposed of myosin - tail (light meromyosin), head & cross-bridges (heavy meromyosin)
    • Thin: composed of Actin (F&G actin), Troponin (TIC subunits) and Tropomyosin (wraps aroun F actin)
  26. Cardiac Muscle
    • Contractile machinery similar to skeletal (actin, myosin, T tubules, SR) - striated
    • Fiber: uninucleated, enriched with mitochondria & lipids, branched
    • Intercalated discs with gap junctions: physically connect adjacent mycocytes - electrical coupling. Muscle functions as an electrical and mechanical "functional syncytium" - rapid synchronous contractions
    • Cardiac action potential 100-250 msec vs. 1-2 msec in skeletal muscle - due to slow calcium channels which bring in extracellular Ca2+ to trigger SR Ca2+ release.
  27. Smooth muscle
    • Hollow organs: GI, reproductive, urinary, respiratory tracts, eyes, vasculature
    • Fusiform (spindle shaped) cells: increased dense extracellular material
    • Slow, prolonged contraction
    • No myofibrils: actin and myosin loosely organized (actin: myosin ~ 12:1) No alignment/striations
    • No T-tubules: SR poorly developed; have "caveolae" - voltage gated Ca2+ channels
    • Dense bodies = Z lines
  28. Mutli unit versus single unit is smooth muscle
    • Multi-unit
    • Eye: ciliary body & iris
    • Similar to skeletal muscle, no electrical coupling - seperate innervation to each fiber (neurogenic)
    • Single unit (visceral/unitary)
    • Hollow organs: GI, reproductive, urinary, respiratory tracts, vasculature
    • Autorhthmicity: rapid transmssion of stimuli via gap junctions hroughout tissue - similar to cardiac (myogenic)
  29. Autorhythmicity
    Rapid transmission of stimuli via gap junctions throughout tissue- similar to cardia (myogenic)
  30. Myo/Sarco
  31. Myocyte
    Muscle cell or muscle fiber
  32. Sarcoplasm
    Cytoplasm or myocytes
  33. SR
    Sarcoplasmic reticulum (ER of myoctyes)
  34. T tubules
    Transvers tubules
  35. A/I bands
    Anisotropic/Isotropic bands
  36. F/G actin
    Filamentous/Glubular actin
  37. Troponin C/I/T
    Tropinin subunits that bind to Ca2+, G-actin (inhibitiory) or Troponin
  38. DHP receptor
    Dihydropyridine receptor (Calcium channel)
  39. Type I fibers
    Slow-twitch (oxidative) or red fibers
  40. Type II fibers
    Fast-twitch (oxidative-glycolytic, glycolytic) or white fibers
  41. Ach
  42. Isometric/Isotonic
    Same length/tension
Card Set
First lecture