Muscle Microanatomy & Sarcomere Function

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Across
  1. 3. Repetitive binding/release of myosin to actin.
  2. 7. Motor protein converting ATP into mechanical energy.
  3. 9. Protein stabilizing thin filament length.
  4. 12. Plasma membrane of a muscle cell.
  5. 13. Force generated by contracting muscle.
  6. 15. Boundary delimiting sarcomeres, anchoring thin filaments.
  7. 17. Region where thick/thin filaments interact during contraction.
  8. 18. Proteins (troponin/tropomyosin) controlling actin-myosin interaction.
  9. 19. Globular protein forming thin filaments.
  10. 22. Process where actin/myosin filaments slide past each other.
  11. 23. Giant protein anchoring thick filaments to Z-discs.
  12. 24. Tubules conducting electrical impulses into the muscle fiber.
  13. 27. Expanded SR regions adjacent to T-tubules, storing Ca²⁺.
  14. 28. Functional unit of muscle contraction (Z-disc to Z-disc).
  15. 29. Proteins (myosin/actin) generating force during contraction.
  16. 31. Organelle storing/releasing calcium ions for contraction.
Down
  1. 1. Myosin head bound to actin during contraction.
  2. 2. Central region of A-band with only thick filaments.
  3. 4. Central line anchoring thick filaments.
  4. 5. Optimal sarcomere length for maximal force generation.
  5. 6. Protein blocking myosin-binding sites on actin at rest.
  6. 7. Long protein bundles (actin/myosin) enabling contraction.
  7. 8. Cytoplasm of a muscle cell, containing glycogen and mitochondria.
  8. 10. Return to resting state after contraction.
  9. 11. Myosin filaments with globular heads for crossbridge formation.
  10. 14. Titin filaments providing recoil after stretching.
  11. 16. Dark region where thick and thin filaments overlap.
  12. 20. Filamentous proteins (actin/myosin) within myofibrils.
  13. 21. Myosin head pivoting to pull thin filaments toward sarcomere center.
  14. 22. Proteins (titin/nebulin) maintaining sarcomere integrity.
  15. 24. Actin filaments with binding sites for myosin.
  16. 25. Connective tissue surrounding individual muscle fibers.
  17. 26. Structure formed by one T-tubule flanked by two terminal cisternae.
  18. 27. Calcium-binding protein regulating tropomyosin position.
  19. 30. Light region of sarcomere containing only thin filaments.