Final answer:
The reflex is an involuntary motor response recorded from skeletal muscles, generated by sensory input without conscious thought. Reflex actions, such as the corneal or stretch reflexes, differ from voluntary movements controlled by the somatic nervous system and involve simple to complex neuronal pathways.
Step-by-step explanation:
The reflex is a pure motor response and can be recorded from any skeletal muscle. This occurs when a sensory input directly generates a motor response without the need for conscious thought. Reflexes can be simple, involving a single neuronal connection, known as somatic reflexes. An example of such a reflex is the corneal reflex, which is the contraction of the orbicularis oculi muscle to blink the eyelid when something touches the surface of the eye. Other reflexes include the stretch reflex, which helps maintain muscle length by causing muscle contraction in response to a stretch detected by muscle spindles. Reflexes are different from voluntary skeletal muscle contractions, which are governed by the somatic nervous system and involve intentional actions. The nervous system modulates the strength of muscle contractions through the frequency of action potentials sent to the muscle fibers by motor neurons. This is known as a graded muscle response. Additionally, the skeletomotor system, which allows for voluntary movements, primarily operates through a two-cell path involving the upper motor neuron (UMN) and the lower motor neuron (LMN).