muscle contraction. microscopic anatomy of skeletal muscle sarcomere contractile unit of a muscle...

MUSCLE CONTRACTION

Microscopic Anatomy of Skeletal Muscle

• Sarcomere• Contractile unit of a muscle fiber

Figure 6.3b

Microscopic Anatomy of Skeletal Muscle• Sarcomere• Thick filaments = myosin• Thin filaments = actin

Figure 6.3c

The Sliding Filament Theory of Muscle Contraction (5 Steps)

• 1) Sarcoplasmic reticulum releases Ca2+

Figure 6.7

The Sliding Filament Theory of Muscle Contraction (5 Steps)

• 2) Ca2+ causes myosin (thick) heads to attach to actin (thin)

Figure 6.7

The Sliding Filament Theory of Muscle Contraction (5 Steps)

• 2) Ca2+ causes myosin (thick) heads to attach to actin (thin)

Figure 6.7

The Sliding Filament Theory of Muscle Contraction (5 Steps)

• 3) ATP gives myosin power to “pull” actin along it

Figure 6.7

The Sliding Filament Theory of Muscle Contraction (5 Steps)

• 3) ATP gives myosin power to “pull” actin along it

Figure 6.7

The Sliding Filament Theory of Muscle Contraction (5 Steps)

• 4) Myosin heads bind to the next site along actin (thin)

Figure 6.7

The Sliding Filament Theory of Muscle Contraction (5 Steps)

• 4) Myosin heads bind to the next site along actin (thin)

Figure 6.7

The Sliding Filament Theory of Muscle Contraction (5 Steps)

• 5) Continued action causes actin to continue to slide along myosin

Figure 6.7

The Sliding Filament Theory of Muscle Contraction (5 Steps)

• 5) Continued action causes actin to continue to slide along myosin

Figure 6.7

Muscle Video• http://www.youtube.com/watch?v=NRzJjx3ANuE

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