different kinds of sensations, different kinds of receptor cells
rod and cone cells of the eye's retina are specialized to respond
to the electromagnetic radiation of light. Hearing: the ear's receptor neurons
are topped by hair bundles that move in response to the vibrations
of sound. Smell: olfactory neurons at the
back of the nose respond to odorant chemicals that bind to them. Taste: receptor cells on the tongue
and the back of the mouth respond to chemical substances that bind
to them. Touch: Meissner's corpuscles are
specialized for rapid response to touch, while free nerve endings
bring sensations of pain.
Illustration, Eade Creative Services Inc. / George
Eade illustrator (rod and cone cells adapted from Scientific American
Vol. 256, No. 2, page 42, 1987). Edited by Dr. Hugo Heyrman.