Senses or Sensory System

Senses, or sensory system, part of the nervous system, gather information — sensations — detected by external stimuli (exteroception — from the environment) and internal stimuli (interoception — from the body). Historically and in varied cultures, it was thought we have five senses, but now we recognize two sensory categories: special (relating to sensory organs — eyes, ears, etc.) and general (visceral, autonomic) senses. They’re further classified by whether nerve fibers run to (afferent) or from (efferent) the central nervous system/CNS. Also see Neurons, Sensory Receptors, and Action Potentials