Final answer:
A sensory receptor is a specialized nerve cell that responds to a stimulus by generating a nerve impulse. There are different types of sensory receptors, including neurons with free nerve endings and encapsulated nerve endings. They can be classified as general senses or special senses.
Step-by-step explanation:
A sensory receptor is a specialized nerve cell that responds to a stimulus in the internal or external environment by generating a nerve impulse. The nerve impulse then travels along with the sensory (afferent) nerve to the central nervous system for processing and to form a response. There are different types of sensory receptors. Some are neurons with free nerve endings, such as pain and temperature receptors. Others have encapsulated nerve endings, like lamellated corpuscles that respond to pressure and touch. There are also specialized receptor cells, such as photoreceptors in the retina that respond to light stimuli.
In terms of classification, there are general senses and special senses. General senses are distributed throughout the body and have receptor cells within the structures of other organs, while special senses have specific organs devoted to them, such as the eye, inner ear, tongue, or nose. The nerve impulse then travels along with the sensory (afferent) nerve to the central nervous system for processing and to form a response.