Transcript Figure 10.6 Levels of Functional Organization in Skeletal Muscle Fiber

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