The upper surface of your tongue is lined with bumps called papillae. In addition to helping you physically manipulate food in your mouth, your papillae contain specialized structures called taste buds, which allow you to detect the flavors in the foods you eat. Inside each taste bud are nerve endings that relay taste sensations to your brain.
Papillae Basics
There are three types of papillae on your tongue. The front and middle sections of your tongue contain fungiform papillae; smaller versions of these papillae appear on the front and sides of your tongue, while larger versions appear further back. Elongated papillae called foliate papillae appear on the rear sides of your tongue. The largest type of papillae, called vallate papillae, appear at the central rear of your tongue's surface. When you eat, the rough surface created by your papillae allows you to grip your food more efficiently for chewing and swallowing.
Taste Bud Basics
Each one of your taste buds contains between 50 and 150 specialized cells called taste receptor cells; these cells are arranged in clusters with a central opening. In turn, each of these central openings contains tiny hairs called microvilli, which send taste signals from your tongue to your brain. Once your brain receives these signals, it sorts them out and classifies them for you. Depending on the classification your brain makes, you perceive each taste as being sweet, salty, bitter, sour or savory.
Diminished Numbers
At birth, you have roughly 10,000 taste buds. Each individual taste bud survives for about two weeks before dying off and being replaced. However, as you age the rate of taste bud replacement slows down, and by the time you reach your later years you may have as few as 5,000 working buds. If you smoke, over time you may experience an additional decrease in your taste bud total. Functionally, a decrease in the number of your taste buds leads to a decrease in your sense of taste.
Reduced Taste Sensations
A number of factors can lead to a dulling or damaging of your taste buds and your sense of taste. In addition to smoking, they include consumption of spicy or extremely sour foods, infections, exposure to extreme heat or cold, use of certain medications and dry mouth. Some individuals also develop sensitivities to certain foods that trigger a temporary reduction in their sense of taste. If you damage a taste bud, in most cases it will heal over time. If you experience an ongoing loss of taste, ask your doctor for advice and guidance.
Considerations
In addition to providing you with a sense of taste, your taste buds protect your health by warning you about potentially harmful substances before you swallow them. They achieve this effect by relaying "off" taste profiles to your brain. Your sense of smell also contributes to safe and harmful taste profiles by giving your brain additional information about the foods you eat.
