___________ potentials can elicit production of __________ potentials that are communicated to CNS.

• A. Action; receptor
• B. Receptor; action
• C. Generator; postsynaptic
• D. Sensory; motor

Answer: (B)

Receptor potentials are graded depolarizations that occur at the sensory receptor in response to a stimulus. When these local changes are large enough, they trigger the generation of action potentials in the primary sensory neuron. Those action potentials then propagate along the neuron’s axon and are carried to the central nervous system. In other words, the initial receptor-level change translates stimulus strength into action potentials that are the actual signals sent to the CNS. This distinction—receptor potentials being stimulus-dependent, graded changes, and action potentials being the all-or-none signals that travel to the brain—is what makes the pairing in this statement correct.