Glossary

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1. actin filaments
   a structural protein of muscle that joins myosin during contaction.
2. myosin filaments
   protein that acts as basis for muscle contraction.
3. tropomyosin
   filamentous protein tha attaches to actin in the thin filaments and then acts, together with another protein, troponin, to inhibit and regulate the attachment of myosin cross bridges to actin.
4. troponin
   a protein found in the thin filaments of the sarcomere of skeletal muscle. A subunit of troponin binds to calcium, and as a result, causes tropomyosin to change position in the thin filament.
5. sarcomere
   the structural subunit of a muscle cell in striated muscle.

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