What does sarcomere mean?
A sarcomere is the basic contractile unit of the striated muscle fibers found in skeletal and cardiac muscle. It forms a repeating segment of a muscle fiber, bounded by structures called Z-lines, and contains thick filaments of myosin and thin filaments of actin. When the muscle contracts, these filaments slide past one another, shortening the sarcomere and drawing the Z-lines closer together. Sarcomeres therefore provide both the physical mechanism of contraction and a useful unit for measuring changes in muscle structure. Their number, length, and alignment can be studied microscopically in cardiac and skeletal muscle tissue, and abnormalities may help researchers identify certain muscle and heart conditions. Although the term is specialized, it names one of the central structural concepts used to explain how striated muscle produces movement.
nounA sarcomere is one of the repeating contractile units that make up the striated muscle fibers of skeletal and cardiac muscle. Each sarcomere contains organized filaments of actin and myosin whose interaction produces contraction.
- The fundamental contractile unit of a striated muscle fiber, extending from one Z-line to the next.
"Microscopic changes in the alignment of the sarcomeres can indicate damage in cardiac muscle."
"The shortening of sarcomeres enables the muscle fiber to contract."
"Researchers examined the arrangement of sarcomeres in tissue taken from the patient's heart."
The plural is regular and takes the ending -es.
"The image shows several sarcomeres arranged in parallel within a muscle fiber."
Every time a muscle contracts, overlapping proteins inside its repeating sarcomeres act like microscopic pulling ropes.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does sarcomere come from?
Sarcomere was formed in the 19th century from combining forms derived from Greek sarx, meaning flesh, and meros, meaning part. The form sarco- usually refers to flesh or connective tissue, while myo- refers to muscle. The resulting term literally designates a part of muscle and came to denote the repeating unit in which the contractile proteins are organized.
Related word forms
How sarcomere is actually used
This is a technical term used chiefly in anatomy, physiology, histology, and related biomedical fields. It normally refers to the organized units of skeletal or cardiac muscle, not smooth muscle.
Easily confused with sarcomere
A sarcomere is a normal structural unit of muscle, whereas a sarcoma is a malignant tumor arising from connective, muscle, or other soft tissues.