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Contraction and Metabolism of Skeletal Muscle

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					Contraction and Metabolism of Skeletal Muscle
Chapter 9 Pgs 295-303

Overview
• Contraction • Motor unit • Muscle twitch and graded muscle responses • Treppe and muscle tone • Isotonic and Isometric contractions • Muscle metabolism

Principles of Muscle Contraction
• Same for contraction of muscle cell and whole skeletal muscle • Muscle tension vs. load • Muscle contraction does not always shorten and move the load!
– Isometric – Isotonic

• Skeletal muscle contraction varies

Graded Muscle Responses
• Refers to a relatively smooth muscle contraction that varies in strength as different demands are placed on the muscle • 2 ways to grade a muscle contraction
– Change frequency of stimulus – Change strength of stimulus

Muscle Response to Change in Frequency of Stimulus

Muscle Response to Stronger Stimuli

Isometric and Isotonic Muscle Contraction

Ex: Squats

Muscle Metabolism—Overview
• Stored ATP • Direct phosphorylation of ATP
– Creatine phoshpate

• Anaerobic respiration
– Glycolysis and lactic acid formation

• • • •

Aerobic respiration Muscle fatigue Oxygen debt Heat production during muscle activity

Muscle Fatigue—How long can you do this?

Oxygen Debt


				
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posted:4/16/2008
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