two classes of taste cells, called papillae and taste cells

two classes of taste cells, called inner and outer hair cells

three classes of taste cells, the two classes of taste cells, hair cells, the papillae, and the taste buds

three classes of taste cells, the Type I glial-like cell, the Type II receptor cell and the Type III presynaptic cell

three classes of taste cells, the Type I systems of nerve endings, the Type II system with receptor cells and the Type III presynaptic system with relay cells