mootoriüksus
The mootoriüksus, often translated as "motor unit," is the fundamental functional unit of skeletal muscle contraction. It consists of a single motor neuron and all the muscle fibers that it innervates. When a motor neuron receives a signal from the central nervous system, it fires an action potential, which travels down its axon to the neuromuscular junction. At the neuromuscular junction, the motor neuron releases neurotransmitters, such as acetylcholine, which bind to receptors on the muscle fiber membrane. This binding initiates a cascade of events that leads to the muscle fiber's contraction.
The number of muscle fibers innervated by a single motor neuron varies depending on the muscle's function.
The recruitment of motor units is a key mechanism for controlling muscle force. When a weak stimulus