文档介绍：Skeletal Muscle
Structure and Function
Chapter 19
Muscle types
Skeletal muscle
Striated
Voluntary
400 skeletal muscles
40-50% of total body weight
Functions
otion and breathing
Postural support
Heat production during cold stress
Smooth muscle
Non-striated
Tonal control
Cardiac muscle
Electrically coupled cells
2006
Structure of Skeletal Muscle: Connective Tissue Covering
Epimysium
Surrounds entire muscle
Perimysium
Surrounds bundles of muscle fibers (Fascicles)
Endomysium
Surrounds individual muscle fibers
2006
Structure of Skeletal Muscle: Microstructure
Sarcolemma
Muscle cell membrane
Myofibrils
Threadlike strands within muscle fibers
Actin (thin filament)
Troponin
Tropomyosin
Myosin (thick filament)
2006
Structure of Skeletal Muscle: Microstructure
A band
Anisotropic (dark)
I band
Isotropic (light)
Z disc
Zwischenscheibe (between zone)
H zone
Hellerscheibe (clear disc)
2006
Structure of Skeletal Muscle: The ere
A I
2006
Structure of Skeletal Muscle: The ere
2006
Z-disc
-actinin
Thick Filaments
Myosin
Figure
Structure of Skeletal Muscle: The ere
Thin Filaments
Actin
Troponin (CTI)
Tropomyosin
2006
Structure of Skeletal Muscle: The ere
Nebulin
defines length of thin filament
Tropomodulin
caps thin filament
Titin
centers thick filament
2006
The Neuromuscular Junction
Synapse between motor neuron and muscle fiber
neuromuscular cleft
Motor end plate
Pocket formed around motor neuron by sarcolemma
Acetylcholine
Causes end-plate potential (EPP)
Depolarizes muscle fiber
2006