sarcomere

noun

sar·​co·​mere ˈsär-kə-ˌmir 

plural sarcomeres

: 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

Examples of sarcomere in a Sentence

Recent Examples on the Web

On a molecular level, sarcomeres—proteins that aid contraction—were shorter and disordered after space exposure, and cells’ mitochondria, responsible for energy production, had become deformed. —Margherita Bassi, Smithsonian Magazine, 26 Sep. 2024

Using high-resolution laser imaging, the scientists also saw details of nerves in the gastric system, small units in muscles called sarcomeres and, when the dye was applied to the mice’s scalp, even structures of the brain’s blood vessels. —Lauren J. Young, Scientific American, 5 Sep. 2024

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

Word History

Etymology

sarco- + -mere

First Known Use

1891, in the meaning defined above

Medical Definition

sarcomere

noun

sar·​co·​mere ˈsär-kə-ˌmi(ə)r 

: 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

Skeletal muscle is a unique kind of tissue, made up of long, thin fibers composed of several different proteins. These proteins interlock like Legos inside fibrous compartments called sarcomeres.

—Gretchen Reynolds, The New York Times Sports Magazine

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., Scientific American

see z line

sarcomeric

ˌsär-kə-ˈmer-ik 

adjective