Glossary
- A band
- The darker of the two bands in striated muscle fibers; contains both actin and myosin myofilaments, which overlap in part causing the darker appearance
- Actin
- protein that makes up most of the thin myofilaments in a sarcomere muscle fiber
- Endomysium
- loose, and well-hydrated connective tissue covering each muscle fiber in a skeletal muscle
- Epimysium
- outer layer of connective tissue around a skeletal muscle
- Fascicles
- bundle of muscle fibers within a skeletal muscle surrounded by perimysium<
- H zone
- Area in the middle of the A-band with only myosin (thick) fibers; this area disappears during muscle contraction
- I band
- The lighter of the two bands; contains only actin myofilaments and titin filaments, which anchor the actin to the Z-discs
- M line
- Anchor in the middle of the dark band of myosin myofilaments
- Myofibrils
- long, cylindrical organelle that runs parallel within the muscle fiber and contains the sarcomeres
- Myosin
- protein that makes up most of the thick cylindrical myofilament within a sarcomere muscle fiber
- Nebulin
- actin-binding protein, which helps to hold the sarcomere together
- Perimysium
- connective tissue that bundles skeletal muscle fibers into fascicles within a skeletal muscle
- Periosteum
- connective tissue that surrounds the outside of bone and merges with the dense regular connective tissue of the tendons, which connect muscle to bone
- Sarcolemma
- plasma membrane of a skeletal muscle fiber
- Sarcomeres
- longitudinally, repeating functional units of skeletal muscle, with all of the contractile and associated proteins involved in contraction
- Skeletal muscle
- striated, multinucleated muscle that requires signaling from the nervous system to trigger contraction; most skeletal muscles are referred to as voluntary muscles that move bones and produce movement
- Skeletal muscle fiber cell
- any of the cells of skeletal muscle tissue. Skeletal muscle fibers are long, cylindrical, multinucleate cells
- Tendon
- dense connective tissue structure that anchors a muscle to bone
- Titin
- connects the myosin filament to the Z-disc and is responsible for the elasticity of muscle contraction
- Troponin
- regulatory protein that binds to tropomyosin on the actin molecule; it binds to calcium to regulate the tropomyosin molecule
- Tropomyosin
- regulatory protein that covers myosin-binding sites to prevent actin from binding to myosin
- Z disc
- Anchors the actin molecules (thin filaments
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Grant and Other Information
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Other text from OpenStaxCollege licensed under CC BY 3.0. Modified by Alice Rudolph, M.A. and Andrea Doub, M.S. for c3bc.
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