Final answer:
Phasic receptors quickly adapt to stimuli and produce a quick burst of action potentials initially, signaling changes in stimulus intensity rather than maintaining a prolonged response.
Step-by-step explanation:
The characteristics of a phasic receptor include the ability to adapt quickly to a stimulus and the tendency to produce a quick burst of action potentials when first stimulated. Sensory receptors like Pacinian corpuscles and Meissner's corpuscles are examples of rapidly adapting or phasic receptors that detect transient pressure as well as low-frequency vibration and flutter.
This ability to quickly adapt means that phasic receptors are not ideal for producing a steady, prolonged response; instead, they signal changes in stimulus intensity. When the stimulus is constant, the rate of action potential production declines, and this decrease is a form of sensory adaptation that allows an organism's nervous system to focus on new and potentially important changes in the environment.