Anatomy and development of the human taste system.

The sense of taste relies on well-defined neuroanatomical structures, namely, the taste buds and afferent nerve fibers. Taste buds are clusters of 50-100 neuroepithelial cells located throughout the oral cavity, including the epiglottis and larynx. They are responsible for the initial transduction process that ultimately results in the perception of bitter, sour, salty, sweet, and umami (savory) sensations. They service as the initial sentinel for a sensory system critical in evolution for distinguishing "dangerous" food components, often perceived as bitter or unpleasant, from "useful" ones, often perceived as pleasant, salty, or sweet. This chapter describes the anatomy and development of the human peripheral taste system and provides historical context for what is presently known about this element of this important sensory system. Its main focus is on the fundamental question of how tastants are perceived-a question that has been of philosophical and scientific interest for more than two millennia. Descriptions of lingual and extralingual taste buds, their blood and nerve supplies, and the associated salivary glands are provided, including details of their microstructure and transduction mechanisms.