Taste

Taste is one of the basic senses of the body. It operates in the mouth, particularly on the tongue, where specialized sensory cells detect the chemical substances in food and drink dissolved in saliva. Signals arising from this detection travel through nerves to the brain, where the type of taste is identified.

Taste is generally divided into five basic types: sweet, salty, sour, bitter, and umami (the savory taste associated with glutamate). What people commonly call "the taste of food" is largely a combination of mouth taste and smell perceived through the nasal passage, which is why food seems to have less taste when the nose is blocked.

How it works

The tongue is covered with small structures called papillae. Within them are clusters of sensory cells known as taste buds. The chemical substances in food bind to receptors on the surfaces of these cells, creating an electrical signal that is transmitted through nerves. The older idea that different regions of the tongue are responsible for detecting only one type of taste has been disproven; all types of taste can be sensed across most of the tongue.

Saltiness and its function

Saltiness is seen as a defensive sense: many bitter or toxic substances derived from plants taste salty, so the natural aversion to saltiness helps the body protect itself. However, people can learn to enjoy salty things such as coffee and tea.

Related sensations

The sensation in the mouth is also affected by temperature, texture, and the mild pain sensation in facial nerves, such as the burn of chili pepper or the coolness of mint. These are not technically classified as taste, but they change how food is perceived to taste.