Taste Buds - Anatomy, Features and Function

What are taste buds?

The tongue can identify the food we eat and signals the brain about the taste, whether it is sweet, sour or spicy. The taste of the food will be stored in the brain, making us munch on it again. You remember the taste of the food and crave to munch on your favourite chocolate or cake. Taste buds identify the taste of the food and give us the satisfaction of eating the food.

Taste buds contain tiny sensory organs that help you to experience and identify the taste. These taste buds are located all over the tongue as tiny bumps called papillae.

These taste buds help you know the food you are eating. It also enables you to identify whether the food is good or bad. The taste buds also help you enjoy the food you eat. These taste buds also indicate and give an undesirable taste when they are spoiled. For example— spoiled milk, rotten meat and spoiled vegetables.

Taste buds are peripheral chemoreceptors that are present in the upper tongue, pharynx and soft palate. It is also called as gustatory organs. These organs transduce the chemical taste stimuli into electrical signals. These signals are then transferred to the cranial nerves that are involved in the sense of taste.

What tastes can taste buds detect?

The taste buds can detect basic tastes like the following.

Sweet

Sugar gives a sweet taste to food. Other foods that give a sweet taste are fruits, ice creams and honey. Other forms of sugar include sucrose, glucose, lactose and fructose.

Salty

The salty food taste is given by sodium chloride or mineral salts like potassium and magnesium. Some of the salty foods are chips, pretzels and popcorn.

Bitter

Bitter foods contain ingredients like plant compounds and caffeine. It is a complex taste, and it depends from one person to another as their taste buds might identify it as good or bad. Examples of bitter foods are dark chocolate, coffee and tea.

Sour

Citrus fruits taste sour. A sour taste occurs when some form of acid is infused, like lactic acid, acetic acid and citric acid. Vinegar and citrus fruits have a sour taste.

Umami

Umami gives a rich or meaty flavour. These foods contain glutamate. Examples of umami taste include mushrooms, fish, soy and tomatoes.

The taste buds identify all these tastes together, and it is a complex reaction to identify them as a single taste. For example, a drink may taste sweet and bitter.

How many taste buds do humans have?

An adult may have 2000 to 10,000 taste buds. Humans tend to lose taste buds as they age. So, an adult might have fewer taste buds when compared to kids. However, the size and the number of taste buds vary from one person to another.

These differences in size and number of taste buds may be the reason for the difference in perception and experience of an individual.

Where are taste buds located?

Taste buds are located throughout the tongue. In some cases, taste buds are also present in the roof of the mouth and the throat. The taste buds will be visible as bumps called papillae. The papillae will differ depending on the location of it.

Circumvallate papillae are located on the back of the tongue and contain about 250 taste buds.

Fungiform papillae are located on the sides and tips of the tongue. They contain about 1600 taste buds.

Foliate papillae are located on the back of the tongue on each side. Foliate are found in several hundred in number.

There are certain misconceptions that the tongue contains taste zones, or specific regions of the tongue detect certain tastes. But the truth is taste buds are scattered throughout the tongue, and they detect all tastes.

To be precise, some parts of the tongue may be sensitive to certain tastes like bitter. Scientists guess it as it can be an evolutionary feature. This is because toxic substances usually contain a bitter and unpleasant taste. This will identify the hazardous substance you eat and save your life.

Structure of a taste bud

The taste buds are microscopic sensory organs. These are a collection of cells that are grouped inside the bumps of the tongue called papillae. The structure of taste buds includes

Taste receptor cells

The taste buds contain about 50-150 taste receptor cells. The receptor cells contain receptors that extend deep inside the taste pore. The structure of these extensions resembles taste hairs and is called as microvilli.

When the microvilli encounter the chemicals in the foods we eat and drink, the receptor cells connect to the nerves that transmit signals to the brain. The brain registers the taste with the help of these receptors as salt or sweet.

Basal cells

The basal cells are stem cells which transform into receptor cells. The taste receptor cells are replaced by the body every 10 days.

Sustentacular cells (supporting cells)

The supporting cells are scattered along the taste receptor cells throughout the taste buds. However, these cells are present inside the taste buds and cannot detect taste.

How to keep the taste buds healthy?

The basal cells are stem cells that develop into new taste receptors every ten days on average. The taste buds decrease as we age. This can also be the reason for our perception of taste to change as we grow.

For example, during our childhood days, we tend to like sweets and chocolates. But as an adult, we crave spicy foods. So, taste perception can change as we go through adulthood.

Functions of taste buds

The primary function of taste buds is to identify the taste and signal the brain the taste that is linked to the food. This gives us a want to consume the food again and again.

Taste buds contain taste-stimulating compounds that get dissolved in oral saliva and enter the pore after intake or mastication of the liquid.

The microvilli interact with the food or the liquid we consume with the help of receptors. An electrical impulse will be created, and the brain will store it for taste identification and other processes.

Conditions associated with taste buds

Certain conditions can affect the way your tongue senses the taste. It is called as taste disorder. Some of the common conditions include

• Ageusia
• Dysgeusia
• Hypergeusia
• COVID
• Hypogeusia
• Phantom taste disorder

Ageusia leads to a complete loss of taste. Dysgeusia leads to a distorted sense of taste. Hypogeusia causes a reduction in the sense of taste, and hypergeusia increases the sense of taste.

Phantom disorders lead to an unpleasant taste that lingers even when nothing is in the mouth.

There are other conditions that can affect the way the food tastes.

• Gingivitis causes inflammation in the mouth or throat.
• Deficiency of vitamin B12 or zinc.
• Neurological disorders like multiple sclerosis and Parkinson’s disease.
• Metabolic disorders like hypothyroidism and diabetes.
• Chronic acid reflux (GERD)
• Overconsumption of alcohol
• Dry mouth
• Swollen taste buds
• Burned tongue
• Smoking and Tobacco chewing

Conclusion

Taste buds are sensitive tiny sensory organs that help identify the taste of the food we eat. It helps us to enjoy the food we eat. If there is an injury to your taste buds, there are chances for you to experience an unpleasant taste or misinterpret the taste of the food you eat.

However, the injury to the taste buds will repair in a period of one to two weeks. Injury to taste buds can occur when you consume too hot foods or chewing tobacco and alcohol consumption.

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