When the nerves in your tongue receive signals from taste bud cells, they pass them on to more nerves and then more, sending the message racing out the back of your mouth, up through a tiny hole in your skull, and into your brain. However, it is detected by the nerves in your tongue, which are specialists at detecting and passing on electric signals. This impulse is so tiny you cannot feel it. These proteins cooperate, rapidly shifting electrically charged atoms called ions here and there, to produce a tiny electrical current inside the cell. The taste bud puts dozens of proteins inside the cell to work. When a taste bud cell is notified that a substance such as food has been detected, it goes into action ( Figure 2). Just as a lock opens only with its matching key, a taste receptor reacts only to its matching type of food particle. This process can be imagined as if the receptors are locks and the food particles are keys. The receptor proteins ignore most of the mix, but when they detect their target food particles they react, notifying their cells that a taste substance has been detected. Taste receptors activate when chewed food mixes with saliva, then flows over and around the papillae like a mushy river. There are five specialized kinds of taste receptor proteins, and each kind detects particles with one of five basic tastes: sweet, sour, salty, bitter, and savory (the “meaty” aspect of foods such as soup broth). The role of taste receptor proteins is to detect substances in your mouth, such as food particles. Thousands of different proteins are found in our bodies, and each plays a special role in the body’s structure and function. Each taste bud cell is attached to nerves at its base, as shown in Figure 2.Īt their very tips, where they poke out from the tongue, each taste bud cell stores tiny proteins called taste receptors ( Figure 1). The cells making up taste buds store special taste receptor proteins at their tips, which respond to particles in food. Each taste bud is made up of a cluster of cells, which are packed together like segments of an orange. Taste buds are hidden beneath the surface of the papillae and barely poke out. The bumps on the surface of the tongue are called papillae. Figure 1 - The structure of the tongue.The taste buds cannot be seen with the naked eye, but if you could zoom in, you would see that each of our papillae contains thousands of taste buds, all peeking out. Only the tips of the taste buds poke through to the surface of the tongue. The real taste buds are made up of delicate cells nestled like sections of an orange beneath the surface of the papillae, where they are well protected. The bumps we see are called papillae, and they are a special tough part of our skin. Most people think they are taste buds, but it is a little more complicated than that ( Figure 1). What do we see when we stick out our tongues? Bumps. However, scientists looking closely have uncovered remarkable details about the pieces making up the taste system, and how these pieces fit together.
How are these signals conveyed from the mouth to the brain? This has long been a mystery. One of the most important properties of food is taste, the combination of sweet, sour, salty, bitter, and savory sensations coming from your tongue. What about a food you dislike? Foods have many different properties that contribute to enjoyment: smell, temperature, and even how they feel in your mouth. Is it pizza? Chocolate? Sushi? Imagine your favorite treat and the pleasure you get from eating it. Each of us lives in a unique taste world, making everyone different in the foods they love and hate. One of the most amazing findings is that taste sensitivity varies from person to person. We all know it starts on the tongue, but how does it really work? Scientists have discovered that taste comes from a chain reaction that starts with sensitive proteins on your tongue, races through taste buds, enters your nerves, and ends in your brain. The ability to taste brings us some of the finest things in life: the sweetness of candy, the saltiness of chips, and the sourness of lemonade.