title: Muscle structure and function--an explanation.
abstract: The structure of vertebrate skeletal muscle is reviewed. The mechanism of muscular contraction and its control is then discussed from the point of view of molecular structure. Contraction takes place by a sliding filament mechanism produced by cross-bridges which form between thick and thin filaments. Control is exercised by tropomyosin and troponin. When the calcium concentration is low, these proteins interfere with the formation of cross-bridges and prevent contraction, but when the calcium concentration is increased, they no longer interfere and contraction proceeds.
mesh_terms: D000199:Actins / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D009119:Muscle Contraction; D009210:Myofibrils / Q000648:ultrastructure; D009218:Myosins / Q000378:metabolism; D014335:Tropomyosin / Q000378:metabolism
chemical_list: D000199:Actins; D014335:Tropomyosin; D000255:Adenosine Triphosphate; D009218:Myosins