The hundreds of visible bumps that cover your tongue are not, in fact, taste buds — they’re papillae like this “fungiform papilla,” seen above. Their job, along with other types of papillae, is to sense touch and taste — in this case, like feeling the texture of a crispy cookie and tasting its sweet flavor in your mouth.
Before you can satisfy your cookie craving, a sugary molecule must first fall into a taste bud through a small opening on the fungiform papilla, seen here in the very center. Inside, dozens of so-called “gustatory” cells recognize it. Gustatory cells matching the molecule’s type — sweet, salty, sour, bitter, or the savory umami flavor — activate and send the signal along, so you experience the right taste.