Final answer:
A strong stimulus results in a faster reflex response due to a more rapid rate of action potentials and the activation of more receptors, leading to a stronger input to the CNS. The response rate is faster, not because the action potentials move faster, but because a stronger stimulus initiates more action potentials and activates more receptors.
Step-by-step explanation:
Sir Charles Sherrington's findings on reflex action times relate to the way in which the intensity of a stimulus affects the reflex response. Although action potentials travel along an axon at a constant speed, regardless of stimulus strength, a strong stimulus can produce a faster response due to two main factors:
The intense stimulus elicits a more rapid train of action potentials, as the sensory receptor fires action potentials at a quicker rate. A stronger stimulus also activates more adjacent receptors, increasing the quantity of action potentials generated simultaneously.
This is significant because it enhances the overall input to the central nervous system (CNS), leading to a more immediate response. Additionally, during the refractory period, the conditions for initiating a new action potential differ. After an action potential occurs, another one cannot begin until the resting state is reached, and if during the relative refractory period, a new action potential requires a stronger stimulus than the initial one.
Finally, it's crucial to understand that a stronger stimulus does not result in a larger action potential, as all action potentials have the same amplitude; what changes is the frequency at which they are initiated and the number of receptors activated.