Structure of Skeletal Muscle (AQA A-Level Biology): Flashcards
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What does skeletal muscle attach to and enable?
What does skeletal muscle attach to and enable?
Attaches to bones; enables voluntary movement
Myofibrils
Myofibrils
Contractile units within muscle fibres; contain actin and myosin filaments
Sarcoplasm
Sarcoplasm
Specialised cytoplasm in muscle fibres
Structure of actin filaments
Structure of actin filaments
Two protein strands twisted in helical arrangement
Structure of myosin filaments
Structure of myosin filaments
Long rod-shaped tails with bulbous heads projecting outward
Sarcomere
Sarcomere
Functional unit of contraction; distance between two Z-lines
What I bands contain
What I bands contain
Only thin actin filaments
What A bands contain
What A bands contain
Both thick and thin filaments overlapping
Slow-twitch fibre characteristics
Slow-twitch fibre characteristics
Contract gradually, sustained periods; rich in mitochondria, myoglobin, blood supply; for endurance
Fast-twitch fibre characteristics
Fast-twitch fibre characteristics
Rapid, powerful contractions for brief periods; high glycogen, myosin, phosphocreatine