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Musculoskeletal System definitions Flashcards

Musculoskeletal System definitions
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  • Skeleton
    The support structure of an organism, composed of mineralized tissues like bone, working with muscles to enable movement and protect internal organs.
  • Myocytes
    Specialized cells in muscle tissue capable of contraction, containing multiple nuclei and packed with myofibrils composed of actin and myosin for movement.
  • Myofibrils
    Rod-like protein structures in muscle cells composed of actin and myosin, organized into sarcomeres, responsible for muscle contraction.
  • Sarcomeres
    Contractile units in muscle fibers, composed of actin and myosin filaments, arranged between Z discs, responsible for muscle contraction and giving striated muscle its characteristic appearance.
  • Myofilaments
    Protein structures in muscle cells, composed of actin (thin) and myosin (thick), that slide past each other to enable muscle contraction.
  • Endoskeleton
    An internal support structure made of mineralized tissues like bone, providing shape, protection, and enabling movement in vertebrates.
  • Actin
    A protein forming thin filaments in muscle fibers, interacting with myosin for muscle contraction, regulated by tropomyosin and troponin, and essential for the sliding filament model.
  • Myosin
    A motor protein in muscle cells that interacts with actin to produce contraction through ATP-dependent movements, forming thick filaments in sarcomeres.
  • Tropomyosin
    A protein that wraps around actin filaments, blocking myosin binding sites, and moves to expose these sites when troponin binds calcium, facilitating muscle contraction.
  • Troponin
    A calcium-sensitive protein that, upon binding calcium, causes tropomyosin to move, exposing myosin binding sites on actin filaments, facilitating muscle contraction.
  • Sarcoplasmic Reticulum
    A specialized smooth endoplasmic reticulum in muscle cells that stores and releases calcium ions to trigger muscle contraction.
  • Myoglobin
    A muscle protein that stores oxygen, aiding in high-demand situations by providing an additional oxygen reserve when hemoglobin supply is insufficient.