Muscular System II

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Muscular System II

• March 29, 2007
• BIOL 203
• Karen Kraus

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Feel the excitment

• Neuromuscular junction
• Acetylcholine release
• Depolarization
• T-tubules
• Ca2 release

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Another day deeper

• Calcium binding
• Troponin conformational change
• Revealing of myosin binding sites

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Cross that bridge when we get to it

• Myosin head attachment
• Power stroke
• ATP attachment
• ATP hydrolysis
• Recocking

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Power stroke
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Problems?

• Myasthenia gravis
• Rigor mortis
• Tetanus
• Botulism

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Response time

• Threshold stimulus
• graded contractions
• motor unit

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Measuring the force

• Myogram
• twitch
• wave summation
• tetanus
• treppe

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Pushing and pulling

• Tension vs. load
• isotonic
• forcegtload
• concentric vs. eccentric
• isometric
• forceltload

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Lifes energy

• ATP
• Creatine phosphate
• Glycolysis
• Oxidative phosphorylation
• Fatigue
• Oxygen debt

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Forcing the issue

• Factors affecting force
• number of fibers contracting
• relative size
• series-elastic elements
• degree of muscle stretch

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Speeding for a long time

• Factors affecting velocity and duration
• muscle fiber type
• myosin ATPase activity
• oxidative vs. glycolytic
• load
• recruitment