However, the tongue has the highest concentration of taste buds that help us in perceiving the sense of taste. Tongue is mainly made of muscles, and is covered by a mucous membrane.
There are several small bumps on the upper surface of the tongue, and these bumps are called papillae. There are different types of papillae on the tongue, and most of the taste buds are found on these papillae. It is said that there are around 10,000 taste buds on the tongue.
Taste Buds - Function and Structure
Each taste bud is a bulbous, flask-like structure with a tiny pore that opens up to the surface of the tongue. Inside this structure, there are two types of cells - gustatory receptors (or taste receptor cells) and supporting cells.
The gustatory receptors have tiny hair-like structures called microvilli that extend out through the taste pore, and on the other end, these cells are connected to neurons that transmit information to the brain. These gustatory cells are replaced with new ones at regular intervals, throughout the life of a human being.
You may have heard that taste buds change with increasing age or do not work in aged people. This is because as you age, some of these structures may stop working, as new gustatory cells are no longer produced to replace older ones. Swollen taste buds on the tongue is another common condition, wherein some of these structures get inflamed and cause pain.
The microvilli that project out of taste buds come into contact with the food you eat and respond to certain tastes. They send messages to the brain regarding its taste. Most taste buds can sense almost all basic tastes like sweet, salty, bitter, sour and savory (or umami). However, it is believed that each taste bud responds strongly to a specific taste.
Earlier, it was perceived that the taste buds on certain areas of the tongue respond strongly to particular flavors, and as per this theory, it was suggested that saltiness and sweetness are sensed by those on the tip of the tongue. Those on the rear end are responsible for bitter flavor, and sour taste is sensed by taste buds on the sides of the tongue.
However, this theory was proved wrong later. Another aspect of taste sensation is that even the olfactory receptors inside nose play a vital role in determining the taste. These cells send messages to the brain beforehand, and the joint efforts of the olfactory receptors, along with the gustatory receptors inside the taste buds, helps us to taste our food.
In short, taste buds on the tongue help us to perceive the sensation of taste. Some people develop a condition called ageusia, which is inability to taste. Partial or reduced inability to taste is hypogeusia. Such taste problems can be caused by damage to taste buds, side effects of certain medication, and infections and other problems with certain nerves.
Some people develop enlarged taste buds, and one of the main reasons for this is accidental biting. There can be various other causes like acid reflux disease and tongue ulcers. Such inflamed taste buds can cause painful bumps on tongue that can cause pain. You may resort to remedies, followed by treatment of the underlying condition (if any).