Olfaction

Abstract

The ability to react to chemical stimuli is a common functional feature of living tissue. The effect that is elicited by the stimulus varies with the functional characteristics of the cells involved, as well as with the nature of the stimulating agent. Some systems show a broad sensitivity whereas others are highly specific and react only to certain stimuli. In the specialised chemoreceptor organs, such as the chemoreceptors of the carotid bodies or the olfactory sense organ, the cells are able to transduce the stimulus into a coded message that provides the central nervous system with information about the strength and nature of the stimulating agent. Though the cells of different tissues show widely different sensitivities and reaction patterns, they seem to have a great deal in common as regards the basic mechanisms of their responses.