Muscle Tissue

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Stephen E. Fish, Ph.D. Mitchell L. Berk,
Ph.D. Marshall University J. C. E. School of
Medicine
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Note to instructors I use these PowerPoint
slides in histology lectures that I give to first
year medical students. Copy the slides, or just
the images into your own teaching media. We all
know that teaching science often requires
compromises and simplification for specific
student populations, or the requirements of a
specific course. Please feel free to offer
suggestions for improvements, corrections, or
additional illustrations. I would be pleased to
hear from anyone who finds my work useful, and am
always willing to make it better. Also, the
images have been compressed to screen resolution
to keep PowerPoint file size down, and I can
provide them at any resolution. Contact me about
the illustrations and Mitchell L. Berk about the
photomicrographs. Stephen E. Fish,
Ph.D. Fish_at_Marshall.edu Berk_at_Marshall.edu
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Introduction to Muscle
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3 Muscle types Skeletal

• Striated (but so is cardiac)
• Voluntary (except in reflexes)
• Strong, fast, discontinuous contractions

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3 Muscle types Cardiac

• Striated (but so is skeletal)
• Always involuntary
• Strong, intermediate speed, continuous repeated
  contractions

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3 Muscle types Smooth

• Not striated
• Always involuntary
• Weak, slow, can sustain continuous contraction

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Definition of a muscle fiber

• A skeletal muscle fiber is a single, long,
  multinucleated cell with flattened nuclei on the
  periphery
• A cardiac muscle fiber is an indeterminate number
  of cells with 1 (occasionally 2) rounded nuclei
  that are joined end to end
• A smooth muscle fiber is a single cell with a
  single speckled hotdog nucleus in the center

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Connective tissue components of a skeletal muscle

• Transfers pull to skeleton
• Brings in vessels nerves
• Type 1 collagen
• Epi peri are dense irregular
• Endo is loose irregular

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Connective tissue component terminology of all 3
muscle types
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Other components of muscle CT
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Skeletal muscle
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Skeletal muscle
Cross section
Longitudinal section
Who is this guy
What is this?
Notice striations on longitudinal sections
Notice texture on the cut ends of cross sections
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Skeletal muscle CT (there is very little
epimysium on our slides)
Perimysium
Endomysium
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Endomysium
Perimysium
Epimysium
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Striations
Dark A bands Light I bands Z line in
your imaginoscope
What is this nucleus in the middle?
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Bands are a feature of myofibrils within a fiber
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Origin of bands lines
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Detail you can see in EM photographs
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Myosin motor heads make cross bridges between the
myosin 2 filament actin
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Ca binds troponin to initiate contraction
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T-tubules the sarcoplasmic reticulum
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Motor units
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