ABSTRACT
This chapter reviews the functional anatomy and perceptual processes of the chemical senses: taste, smell, and the common chemical sense. It focuses on the properties of those senses which have the most salient impact on the collection and interpretation of sensory evaluation data. Sensory receptors responsible for olfaction are located in the olfactory epithelium at the top of the nasal passages. Taste sensations are consciously experienced when neural signals originating at the receptor cells are relayed through their connecting neural pathways and are received by the appropriate area of the central nervous system. Thresholds are often thought of as that concentration of stimulus which defines the lower limit of sensitivity of the sensory system. In addition to the probabilistic nature of thresholds, their value is also dependent on the expectations brought to the threshold test by the subject. Thresholds are classically thought of as determinations made on individual subjects.
