Special Senses

Special senses refer to external senses with specialized organs to detect vision (eyes), hearing (ears), balance/spatial orientation (inner ear), smell (nose), and taste (tongue). They require a distinct organ to function (unlike general senses, including touch, distributed across the body). Sensory receptors in the sensory organs transduce sensory information (light, sound waves, chemicals) into electrical signals that are sent via cranial nerves to specific sensory cortices in the brain for processing. Sensation is carried to the brain by special somatic afferents — and specialized neurons in specialized nerves transmit “instructions” back out to the sensory organs (like olfactory nerve for smell and vestibulocochlear nerve for hearing and balance). Also see Sensory Perception, Senses, and Exteroception. Special senses include:

• Vision (sight) is detected by the eyes, which capture light and convert to visual information.
• Hearing (audition) is detected by the ears, which pick up/translate sound waves to auditory signals.
• Balance (vestibular function) is detected by inner ear’s semicircular canals that sense head movement, body position, balance, spatial orientation (so we can walk on two legs).
• Smell (olfaction) is detected by nasal cavity’s olfactory receptors responding to airborne chemicals. 
• Taste (gustation) is detected by tongue’s taste buds that sense dissolved chemicals in food.