The tongue is a slab of mucous membrane. Its upper surface is studded with taste buds. Located in the taste buds are taste cells. These actually receive the sensation of taste. Taste buds look something like microscopic rosebuds. To a large extent, we taste salt with the tip, sweet in the middle, bitter in the rear and sour along the sides of the tongue. Taste buds are also found on the upper as well as on the lower side of the tongue, though they are largely concentrated on the upper surface. Some taste buds are scattered around the oral cavity.
The tasting action is a chemical process, like smell. Food must be liquefied before the real taste can emerge. The saliva helps in doing this together with the teeth that grind the food into small particles. Once liquefied, it binds to the receptors of the taste buds, a minute current is generated and passed onto the brain. The brain then identifies the taste.
Substances may taste different to different people. Also people learn to accept tastes, which they had previously found horrid. For example children detest bitter food, but gradually accept them as in the case of bitter gourd. Unlike the other sense organs, the sense of taste does not diminish with age.