Intermediate
Technical
In the Industry Vocabulary Test
motor unit
A motor neuron and all the muscle fibers it innervates, functioning as the basic unit of muscle contraction.
Full Definition
A motor unit consists of a single motor neuron and all the skeletal muscle fibers it innervates through its axon branches. Motor units vary in size from small units with few muscle fibers (for fine motor control) to large units with hundreds of fibers (for powerful movements). The recruitment and firing patterns of motor units determine the force and precision of muscle contractions, making them fundamental to understanding neuromuscular control.
In Context
- "Electromyography recorded the firing patterns of individual motor units during the task." — movement analysis study
- "ALS progressively destroys motor units, leading to muscle weakness and atrophy." — disease mechanism paper
Don't confuse with
muscle fiber
motor neuron