What term describes specialized cells that respond to stimuli such as pain or touch?

The correct term that describes specialized cells capable of responding to stimuli such as pain or touch is receptors. Receptors are specialized structures found in sensory organs that detect specific types of stimuli, such as mechanical pressure (touch), chemical signals (taste, smell), or temperature changes. When these receptors are stimulated, they convert the physical stimulus into electrical signals that can be transmitted to the nervous system.

In this context, effectors generally refer to muscles or glands that produce responses to stimuli after the information has been processed by the nervous system. Neurons are the primary cell type within the nervous system responsible for transmitting these signals, but they are not the cells directly responsible for sensing stimuli. Axons are the long projections of neurons that carry electrical impulses away from the neuron, but they do not directly sense external stimuli themselves.

Understanding the role of each of these terms helps clarify their specific functions within the sensory and nervous systems.