Download Figure 10.6 Levels of Functional Organization in Skeletal Muscle Fiber

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Figure 10.6 Levels of Functional
Organization in Skeletal Muscle Fiber
Figure 10.6
Figure 10.7 Thick and Thin
Filaments
Figure 10.7
• Sliding filamentsdecreasetheory
in fiber length
Sliding 30%
filament
• Explains the relationship between thick and thin
filaments as contraction proceeds
• Cyclic process beginning with calcium release
from SR
– Calcium binds to troponin
– Trponin moves, moving tropomyosin and exposing
actin active site
– Myosin head forms cross bridge and bends toward H
zone
– ATP allows release of cross bridge
appearance of a Sarcomere during the
Contraction of a Skeletal Muscle
Fiber
Figure 10.8
Tension
• Created when muscles contract
• Series of steps that begin with excitation at the
neuromuscular junction
–
–
–
–
Calcium release
Thick/thin filament interaction
Muscle fiber contraction
Tension
Figure 10.9 An Overview of the
Process of Skeletal Muscle
Figure 10.9
Control of skeletal muscle activity
occurs at the neuromuscular junction
• Action potential arrives at synaptic terminal
• ACh released into synaptic cleft
• ACh binds to receptors on post-synaptic neuron
– Action potential in sarcolemma
Figure 10.10 Skeletal Muscle
Innervation
Figure 10.10a, b
Figure 10.10 Skeletal Muscle
Innervation
PLAY
Animation: Neuromuscular junction
Figure 10.10c
Excitation/contraction coupling
• Action potential along T-tubule causes release
of calcium from cisternae of SR
• Initiates contraction cycle
•
•
•
•
Attachment
Pivot
Detachment
Return
Figure 10.12 The Contraction
Cycle
Figure 10.12
Figure 10.12 The Contraction
Cycle
Figure 10.12