noun
- A contractile filament in muscle cells that is composed of thick and thin protein filaments and is responsible for muscle contraction.
Usage: Biology/anatomy term; Usually used in plural form (myofibrils)
Examples
- Myofibrils are the basic contractile units of skeletal muscle.
- Each muscle fiber contains hundreds of myofibrils arranged in parallel.
- The myofibrils are composed of repeating units called sarcomeres.
- During muscle contraction, the myofibrils shorten as thick and thin filaments slide past each other.
- Damage to myofibrils can result in muscle weakness or injury.