Skeletal Muscles (AQA A-Level Biology): Flashcards
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10 cards from this deck
Antagonistic muscle pairs
Antagonistic muscle pairs
Muscles working in opposite directions; one contracts, other relaxes
Sarcomere
Sarcomere
Functional unit of muscle contraction between two Z-lines
Sliding filament mechanism
Sliding filament mechanism
Filaments slide past each other without shortening themselves
A-band width during muscle contraction
A-band width during muscle contraction
Remains constant (myosin filament length unchanged)
Role of tropomyosin in muscle
Role of tropomyosin in muscle
Blocks/unblocks actin binding sites; regulates contraction
Sarcoplasmic reticulum function
Sarcoplasmic reticulum function
Stores calcium ions; releases them to trigger contraction
Effect of calcium ions on tropomyosin
Effect of calcium ions on tropomyosin
Causes tropomyosin to shift, exposing actin binding sites
Cross-bridges in muscle
Cross-bridges in muscle
Formed when myosin heads attach to actin filaments
Why muscle relaxation requires ATP
Why muscle relaxation requires ATP
Active transport of calcium back into sarcoplasmic reticulum
Phosphocreatine system duration
Phosphocreatine system duration
About 10-15 seconds of maximum effort