weight and work skeletal muscle. definitions motor unit: a motor neuron and all muscle fibers it...
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Weight and WorkSkeletal Muscle
Definitions• Motor Unit: a motor neuron and all muscle fibers it
innervates.
• Twitch: single contraction in response to a single
stimulus/AP.
• Isotonic: muscular contraction where constant
tension continues while the length of the muscle
changes.
– Concentric
– Eccentric
• Isometric: muscular contraction against resistance
in which the length of the muscle remains the same.
Isotonic Contraction
Isometric Contraction
Work
• Work is accomplished only when an object is
moved.
• Work = Force X Distance
• Force = muscle tension required to overcome the
load (weight of the object).
• In an isometric contraction where no object is
moved (muscles do not change length) the work
done = zero.
Load/Velocity relationship
• Load is an important determinant of
shortening velocity. Load =
velocity
Load/Velocity Relationship
3 Muscle Fiber Types
Slow Oxidative
Fast Oxidative Fast Glycolytic
Postural muscles
Bird flight muscles
Mammal breast muscles
Lithobates pipiens• Referred to as Rana pipiens
also.
• Opportunistic feeders
• Occurs through much of US
and Canada (cosmopolitan)
• Status is controversial:
widespread, but most
populations throughout
range are decreasing rapidly.
• Commonly used in research.
HOMEWORK!!!!• Write an entire lab report, again.
• Include answers to ALL labscribe
questions WITHIN the body of the
paper.
• Follow my formatting
instructions!!!!!!
• Due on November 28/29.
Next Week…
• Have a GREAT Thanksgiving!!!
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