Sensory System

Abstract

The sensory system provides information to the central nervous system about the external world (exteroceptive) and the internal environment (interoceptive). Impulses traveling toward the central nervous system are called afferent impulses. Afferent information may be transmitted as conscious data that are perceived by the organism and then used to modify behavior; as unconscious data that, although used to modify behavior, remain unperceived by the organism; or as both conscious and unconscious data. Afferent impulses are functionally subdivided into 4 categories: general somatic afferent impulses (from skin, striated muscles, and joints), general visceral afferent impulses (largely unconscious, from serosal and mucosal surfaces, smooth muscle of the viscera, and baroreceptors), special somatic afferent impulses (relating to vision, hearing, and equilibrium), and special visceral afferent impulses (relating to taste and smell).