myofibril
/ˌmaɪoʊˈfaɪbrɪl/
noun
- A tiny thread-like structure in a muscle cell that helps the muscle contract and relax.
- When you exercise, the myofibrils in your muscles grow thicker and stronger.
- Under a microscope, you can see the myofibril running through the muscle tissue.
- Each myofibril is made of proteins that slide past each other to make the muscle shorten.