The process of muscle contraction begins at the behest of the brain. From the brain, the command is transmitted to the spinal cord (1), from where the command is transmitted along the motor nerve (2-3) to the surface (6) of the striated muscle cell (4), whereby the muscle contracts. Each nerve cell is linked with hundreds of muscle cells.

Explanation of the numbers in the picture: 1. spinal cord, 2. motor neuron, 3. motor neuron axon. 4. muscle cell, 5. muscle cell nucleus, 6. neuromuscular junction, 7. fascicle (a bundle of skeletal muscle fibers).