Sensory Reception and Processing

Our senses are how the body notices change, both in the world around it and within itself. Two related but distinct processes are involved: sensation, simply becoming aware that a stimulus has occurred, and perception, actually interpreting what that stimulus means — and both of these happen in the brain, not at the receptor itself, which only detects and encodes the stimulus as a nerve impulse.

Receptors can be sorted in two independent ways. By location, they are either exteroceptors, sitting at or near the body surface and picking up external stimuli like sound, light, touch, taste and smell, or interoceptors, sitting inside visceral organs and blood vessels and picking up internal stimuli; a special subclass of interoceptor, the proprioceptor, sits in skeletal muscles, tendons, joints, ligaments and the connective tissue around bones and muscles, and reports on the body's own position and movement. By the type of stimulus they detect, receptors are classed as mechanoreceptors (pressure and vibration — found in the cochlea and the semicircular canal/utriculus), chemoreceptors (chemicals — found in taste buds and the nasal epithelium), thermoreceptors (temperature — fo …