HUMAN TASTE TEST: Taste is the ability to respond to dissolved molecules and ions called tastants, which humans detect via taste receptor cells, which are clustered into taste buds. The tongue has about 10,000 taste buds. When these detect food particles, they send signals to the brain carrying information about their "taste." Each taste bud contains 50-100 taste cells, representing the five taste sensations: salty, sour, sweet, bitter and umami (the response to acidic salts like MSG, often used as a flavor enhancer in Asian dishes, processed meats, and processed cheeses).
Each taste cell has receptors that bond to specific molecules and ions in response to the various taste sensations, connected to a sensory neuron leading back to the brain. So taste -- like all sensations -- resides in the brain. That's the reason different people like different things. Although a single cell may have several types of receptors, one may be more active than the others, so certain tastes will be preferred by that individual. Also, no single taste cell contains receptors for both bitter and sweet tastants.
ABOUT THE TONGUE: The tongue is a versatile group of muscles anchored in the mouth and throat. It is integral to creating articulate speech and other noises. Its top surface is covered by taste buds able to detect the bitter, salty, sour, sweet, and umami (or savory) qualities of food. The tongue, which acts both as a voluntary and involuntary muscle, filters germs and also moves food around within the mouth before transferring it to the esophagus.
The Biophysical Society contributed to the information contained in the TV portion of this report. This report has also been produced thanks to a generous grant from the Camille and Henry Dreyfus Foundation, Inc.