Neuromuscular

Exercise: Muscle hypertrophy


H & E stain

 
Bimodal distribution of fiber size
  Larger fibers are hypertrophied and slightly paler than normal sized fibers


Gomori trichrome stain

 
Bimodal distribution of fiber size
  Larger fibers are hypertrophied and slightly paler than normal sized fibers
  Some larger muscle fibers with intermediate degrees of sarcoplasmic staining are present


ATPase pH 9.4

 
Fiber types
  Larger, hypertrophied fibers are Type 2 (Dark)
  Smaller fibers are Type 1 (Light)


ATPase pH 4.3

ATPase pH 4.6
Fiber types
  Larger, hypertrophied fibers are Type 2 (Light)
  Smaller fibers are Type 1 (Dark)
  Type 2C fibers (Intermediate) are absent
Fiber types
  Some larger, hypertrophied fibers are Type 2A (Very Dark)
  Some larger, hypertrophied fibers are Type 2B (Intermediate)
    The degree of staining of 2B fibers is unusually variable
  Smaller fibers are Type 1 (Light)


Cytochrome oxidase stain

SDH stain

PAS stain
Mitochondrial stains
  Larger, hypertrophied type 2 fibers are Light
  Smaller, type 1 fibers are dark
  3 populations of fibers: Pale (2B), Intermediate (2A) or Dark (1) staining
Larger muscle fibers are darker stained

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11/18/2014