How do you taste? | The Health Culture

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Beatles Russian nesting dolls from Russian Legacy

The reason animals, including humans, have a sense of taste is so we’ll know what’s good to eat and what’s not. But exactly how does taste happen? We experience taste as happening on the tongue, and advertisers often appeal to our “taste buds.” But is there really such a thing as a taste bud?

You can think of taste as a nested set of structures, a little like a collection of Russian nested dolls. In the Yellow Submarine dolls pictured here, John contains Paul contains George contains Ringo contains Yoko (Is that Yoko?). With taste, the tongue contains papillae, which contain taste buds, which contain taste cells, which contain taste receptors.

Source: National Geographic

The Latin word “papula” means pimple or swelling. Papillae are little swellings or projections on the top of the tongue. The photo of papillae on the right was taken through a microscope.

The chemical molecules of food, dissolved in saliva, fill the spaces between the papillae. There really is such a thing as a taste bud, and the sides of papillae are lined with them. Each taste bud is exposed to the surrounding fluid through an opening called a taste pore. Microscopic hairs poke out through the taste pores and interact with whatever food molecules they find. This is similar to the way we smell odors, where microscopic hairs detect gaseous molecules in the air.

Source: Colorado State University

You can see why they call it a bud (see diagram left). A taste bud looks like a poppy pod that hasn’t yet opened, with little hairs like stamens sticking out the top.

So the tongue contains papillae which contain taste buds. At the next level of nesting, taste buds contain taste cells. You can picture taste cells by imagining a bunch of bananas that are joined at both ends. That cluster of taste cells forms a taste bud.

At the final level of nesting, taste cells contain taste receptors (the little black dots in the diagram).

The taste receptors for bitter, sweet, and savory are proteins that change shape in response to the chemicals in food. When taste receptors change shape, they send a signal along nerve fibers in the taste cell. The nerves exit the taste bud at the bottom of the bunch of bananas, so to speak, and the signal gets sent to the brain, which is ultimately where taste happens.

The structures involved in taste aren’t exactly like nested dolls. There’s only one Paul inside of John, but there are many taste buds in a papilla, many taste cells in a taste bud, and many taste receptors in a taste cell. The terms papillae, taste buds, and taste receptors come up in subsequent posts, which is why I’ve explained them here.

I should also mention that the tongue has different types of papillae, and not all types have taste buds.