A receptor potential is best described as:

• A. A chemical released at synapses
• B. A graded potential arising from sensory receptors (vary with strength of stimulus)
• C. A rhythmic oscillation in neural networks
• D. An all-or-none action potential sent along axons

Answer: (B)

Sensory receptors produce a graded change in membrane potential when they are stimulated. This receptor potential grows in amplitude as the stimulus becomes stronger, so its size directly reflects stimulus intensity. It is a local, variable signal at the receptor, not an all-or-none spike. If the depolarization reaches threshold, it can trigger action potentials in the sensory neuron, but the receptor potential itself is not an all-or-none event. It’s also not a chemical released at a synapse, nor a rhythmic oscillation in neural networks. So the best description is a graded potential arising from sensory receptors that varies with stimulus strength.