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MUSCLE PHYSIOLOGY

Sielrtal Musde: Excitation-Contraction Ciiupling II

During musde contraction, thin filaments of each inyofibril slide deeply between thick filaments, bringing Z bands doser togeiher and shortenmg sarcomeres. A bands remain same width, but I bands narrowed. H /nnes also narrowed or disappear as thin filaments encioai li upon them. Mynfibrils, and consequently musde fibers (musde cclls), fasddes, and musde as whole grow thic ker. Dunng relaxation, reverse occurs

Figurę 3.4 Muscie Contraction and Relaxation__

rhe sliding oł the attin and myosin filaments past one another results in contraction. This sliding action is Ihe result of tbe cydical binding (cross bridge formation) of adin and myosin.

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