Which type of nerve fibers are responsible for reflex actions?

Reflex actions are primarily mediated by interneurons, which play a crucial role in the central nervous system. These neurons act as connectors or intermediaries between sensory (afferent) neurons and motor (efferent) neurons. When a sensory neuron detects a stimulus, it transmits an impulse to a spinal cord interneuron, which processes the information and triggers an immediate response by connecting to motor neurons. This pathway allows for quick, involuntary responses to stimuli without the need for conscious thought, thereby facilitating reflex actions.

In contrast, afferent fibers carry sensory information to the central nervous system from the periphery, while efferent fibers convey signals from the central nervous system to muscles or glands, initiating movement or secretion. Although motor fibers are indeed involved in the reflex arc, they do not perform the processing role that interneurons do. Thus, the critical function of interneurons in coordinating reflex actions highlights their significance in the overall response mechanism.