: any of the repeating, contractile, structural subunits of striated muscle cells (as of skeletal or cardiac muscle) that are composed of the protein filaments actin and myosin
Basically, during contraction a sarcomere shortens like a collapsing telescope, as the actin filaments at each end of a central myosin filament slide toward the myosin's center.—Jesper L. Andersen et al.see z line
Recent Examples on the Web More myofibrils will increase the mass of a muscle cell while more sarcomeres will increase the length. —Popular Science, 1 Jan. 2019 Our bodies rebuild these tears by adding either sarcomeres, which are fibrous proteins inside muscle cells, or myofibrils—chains of rod-like units also in muscle cells that give them their striped appearance. —Popular Science, 1 Jan. 2019 The basic functional units of muscle tissue are called sarcomeres. —Alexa Tucker, SELF, 19 Aug. 2018
These examples are programmatically compiled from various online sources to illustrate current usage of the word 'sarcomere.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.
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