Final answer:
Muscle tone is maintained by the nervous system's cyclical activation of intrafusal muscle fibres, not the activation of intrafusal fibres by alpha motoneurons. Alpha motoneurons activate extrafusal fibres, while gamma motoneurons activate intrafusal fibres, which are part of the muscle spindle and responsible for sensing stretch.
Step-by-step explanation:
The activation of intrafusal fibres by alpha motoneurons does not create muscle tone; instead, muscle tone is primarily created by the constant, low-level contraction of intrafusal muscle fibres, which are activated by alpha motoneurons. Intrafusal fibres are part of the muscle spindle and play a role in sensing muscle stretch, and they are activated by gamma motoneurons, not alpha. These muscle spindles provide feedback to the nervous system, allowing it to maintain the necessary muscle tone for posture and stability. Muscle tone is maintained through a complex interaction between the nervous system and skeletal muscles, resulting in the cyclical activation of a few motor units at a time. Variations in the frequency of motor neuron signalling can lead to different types of muscle contractions, ranging from a single twitch to complete tetanus, depending on the frequency and summation of action potentials. The frequency and number of motor neurons firing action potentials affect the tension produced in the skeletal muscle, leading to graded muscle responses for varying force production.