What is the component of the nervous system that directly activates skeletal muscle?

The component of the nervous system that directly activates skeletal muscle is the lower motor neurons. These neurons are responsible for transmitting signals from the spinal cord and brainstem directly to the muscles, causing them to contract. Lower motor neurons innervate skeletal muscles at the neuromuscular junction, where electrical impulses trigger muscle contractions.

While upper motor neurons play a role in the voluntary control of movement by sending signals to lower motor neurons, they do not directly innervate skeletal muscle. Instead, the command for movement originates in the upper motor neurons, which communicate with lower motor neurons that in turn activate the muscle fibers.

The peripheral nervous system encompasses all of the neural pathways that link the central nervous system (including both upper and lower motor neurons) to the limbs and organs, but it is the lower motor neurons specifically that have the direct action on skeletal muscle. The cerebellum is involved in coordination and balance rather than the direct activation of skeletal muscle.