What are the components of a reflex arc?

What are the components of a reflex arc?

• A. Receptor, sensory neuron, integration center, motor neuron, and effector.
• B. Receptor, interneuron, motor neuron, and muscle fiber
• C. Stimulus, receptor, brain, and target organ
• D. Afferent, efferent, and synapse

Answer: (A)

A reflex arc is a simple neural pathway that mediates a reflex action, with a receptor detecting a stimulus and generating the signal that travels through a sensory neuron to a CNS integration center, then via a motor neuron to an effector that produces the response. The integration center processes the input (often in the spinal cord) and can involve interneurons, especially in polysynaptic reflexes, though some reflexes are monosynaptic with a direct connection between sensory and motor neurons. This full chain—receptor, sensory neuron, integration center, motor neuron, and effector—captures the essential structure of a reflex arc. Some options miss essential parts or misplace the processing center—like listing only brain involvement, or omitting the receptor or integration center, or naming the effector without linking it to the CNS processing. That’s why the complete set best describes the reflex arc.

A reflex arc is a simple neural pathway that mediates a reflex action, with a receptor detecting a stimulus and generating the signal that travels through a sensory neuron to a CNS integration center, then via a motor neuron to an effector that produces the response. The integration center processes the input (often in the spinal cord) and can involve interneurons, especially in polysynaptic reflexes, though some reflexes are monosynaptic with a direct connection between sensory and motor neurons. This full chain—receptor, sensory neuron, integration center, motor neuron, and effector—captures the essential structure of a reflex arc.

Some options miss essential parts or misplace the processing center—like listing only brain involvement, or omitting the receptor or integration center, or naming the effector without linking it to the CNS processing. That’s why the complete set best describes the reflex arc.