Senses

Senses, media through which stimuli in the environment of an organism act on the organism (external senses); also, the internal senses, which report on the the internal state of the organism (through thirst, hunger, pain, etc.). The organs of sense—the eye ear, skin, etc.—contain specialized cells and nerve endings that communicate with centers in the nervous system. Sense organs may be stimulated by pressure (in touch, hearing, and balance), chemical stimulation (smell, taste), or electromagnetic radiation (vision, heat sensors).