FoundationalConceptsNeuroscience

Structural cells Pore Microvilli

of tongue

Cranial nerve fibers

to brain

Taste receptor cells

Ps

Gustatory stem cells

Figure 13.1. Taste bud components.

Five types of taste receptor cells have been described in the human
mouth: salt, sour, bitter, sweet, and umami. They are characterized
by different kinds of taste receptor proteins, responding to different
kinds of substances floating around in the mouth, and they give rise
to signals that are associated with different perceptual experiences of
tastiness.

Salt. Salt is sodium chloride (NaCl), mostly. Put some NaCl (table salt)
into the mouth and experience the taste of saltiness. NaCl crystals in
the mouth rapidly become Na* and Cl ions in solution. The proteins
on taste receptor cells related to the perceptual experience of saltiness
are thought to be channels that allow sodium ions to flow across the