Final answer:
The stretch reflex and Golgi tendon organs (GTOs) both serve important roles in regulating muscle tone. The stretch reflex causes muscle contraction upon sudden stretching, while GTOs can induce relaxation when there is too much muscle tension. Together, they work to balance muscle activity, but in the context of spasticity, an overactive stretch reflex can increase muscle tone, while GTOs attempt to decrease it.
Step-by-step explanation:
Role of the Stretch Reflex and Golgi Tendon Organs in Spasticity
The role of the stretch reflex and Golgi tendon organs (GTOs) in muscle spasticity is an integral part of understanding how the nervous system regulates muscle tension. The stretch reflex is initiated when muscle spindles, which are stretch receptors within the muscle, are activated due to a sudden stretch of the muscle. This reflex action results in the contraction of the stretched muscle to resist further stretching and maintain muscle length. When the muscle contracts, the antagonist muscles are inhibited to allow for this contracting action.
On the other hand, Golgi tendon organs are tension receptors located within the tendons that monitor the force of muscle contraction. GTOs serve to decrease muscle tension; when there is excessive contraction, GTOs can initiate a reflex that causes relaxation of the muscle, thereby preventing muscle damage and aiding in the reduction of spasticity. This is known as the inverse stretch reflex.
In the context of spasticity, the stretch reflex can be hyperactive due to damage in the central nervous system, particularly in cases involving upper motor neuron lesions, leading to an increase in muscle tone or hyperflexia. Conversely, GTOs act to reduce excessive muscle contraction. Therefore, the correct characterization of the relationship between the stretch reflex and Golgi tendon organs in relation to spasticity is that the stretch reflex increases muscle tone, while GTOs decrease muscle tension (Option C).