The First Four: Sour, Sweet, Salty, and Bitter

The perception of taste has its physiological origin in the taste receptor cells. These are found in the taste buds, which are embedded in tiny protrusions (papillae) located primarily on the top of the tongue but also distributed over the soft palate, pharynx, epiglottis, and the entrance to the esophagus. There are approximately 9,000 taste buds on the human tongue, clustered together in groups of 50 or so. Each taste bud is made up of 50–150 taste receptor cells. Like other cells, they are encapsulated in a cell membrane, and it is this membrane that holds the secret of taste perception.