Sensory Receptors
« Back to Glossary IndexSensory receptors, also called specialized sensory receptors or sensory neurons, are neurons (nerve cells) with receptors for the special senses (vision, hearing, smell, taste, equilibrium), which help identify, interpret, and respond to external stimuli. There are also internal general senses receptors for connective tissues (bind organs/cells together, provide support/protection, store fat), epithelial tissues (line body’s outer surfaces/internal cavities, form glands), muscle tissues (allow body to move), and nervous tissues (electrically active, release chemical signals for neural/other cellular communications). Receptor cells in tissues and organs throughout the body are the peripheral nervous system (PNS) — they convert stimuli into electrochemical signals (or nerve impulses) and send to the central nervous system (CNS). Also see Sensory Processing. Sensory receptors are classified by three different criteria:
- Structure, in relation to type stimuli. Three cell structures: neurons with free nerve endings, neurons with encapsulated endings, and specialized receptor cells.
- Location, in relation to type stimuli. Three locations: exteroceptors (external stimuli), interoceptors (internal stimuli), proprioceptors (stimuli from body’s movement in space).
- Function, on the basis of sensory transduction — how mechanical stimuli, light, or electrochemical signals change cell membrane potential (difference in electrical impulses inside-to-outside the cell):
Electroreceptors: electric receptors
Thermoreceptors: temperature
Chemoreceptors: chemical receptors
Photoreceptors: light receptors
Osmoreceptors: sodium-water
Nociceptors: pain receptors
Mechanoreceptors: tactile receptors
Vestibular: balance-movement
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