Chapter 12 vocab

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Chapter 12 vocab
2013-11-12 23:49:59
Physiology chapter 12 vocab

physiology chapter 12 vocab
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  1. agonist muscle
    the prime mover of any skeletal movement
  2. atagonistic muscles
    flexors and extensors that act on the same joint to produce opposite actions
  3. epimysium
    the fibrous connective tissue proteins w/in the tendons extended around the muscle in an irregular attangements forming a sheath
  4. fascicles
    connective tissue from this outer sheath extends into the body of the muscle, subdividing it into columns
  5. perimysium
    each of these fascicles is thus surrounded by its on connective tissue sheath
  6. sarcolemma
    each myofibers is surrounded by a plasma membraneĀ enveloped by a thin connective tissue layer called an endomysium
  7. A bands
    dark bands
  8. I bands
    light bands
  9. Z lines
    In an electron microscope a thin dark lines can be seen in the middle of the I bands
  10. motor end plate
    the specialized region of the sarcolemma of the muscle fiber at the neuromuscular junction
  11. Acetylcholine (ACh) released by the axon terminals diffuses across the synaptic cleft and bind to ACh receptors in the plasma of the end plate, thereby stimulating the muscle fiber.
  12. motor unit
    each somatic motor neuron together with all of the muscle fibers that it innervates
  13. recruitment
    when contractions of greater strength are required, larger and larger motor units are activated
  14. myofilaments
    smaller structures contained in each myofibril
  15. thick filament (A band)
    are primarily composed of the protein myosin
  16. Thin filaments (I band)
    are primarily composed of the protein actin
  17. H band
    the central lighter regions of the A bands contain only thick filaments
  18. sarcomers
    the stuctural subunit of the myofibril in the striated muscle: equal to the distance between two successive Z lines
  19. cross bridges
    sliding of the filaments is produced by the actions of numerous cross bridges that extend out from the myosin toward the actin.