The Chemical Senses Taste and Smell

Did you know that The Chemical Senses Taste and Smell? In fact, they both rely on your sense of smell. The human body is an amazing machine. In addition to our ability to think and feel, we have five senses that allow us to interact with the world around us. These senses are taste, smell, touch, sight, and hearing. Each of these senses plays a vital role in our everyday lives. Today, we’re going to focus on the two senses that allow us to taste and smell the world around us.

Chemical Receptors

Have you ever thought about how you feel about food taste or the Smell of any perfume? The answer lies that all these perceptions are only possible through Chemical Receptors like taste buds or olfactory receptors. Chemical Receptor is responsible for the stimulation of all types of chemical senses. Now the question comes into our mind: what are chemical senses? We are going to describe both olfaction and gustation here. To know all about it, let’s explore further here! 

What are The Chemical Senses Taste and Smell? 

Chemical senses respond to the chemicals present in air or food. When we eat foods, taste buds detect the chemicals, and you’ll feel the taste. Similarly, chemical receptors sense some chemicals in aroma when we sense perfume. Both odor and taste sensations interact as foods are detected in combination with gustatory and olfactory senses. 

Examples

Olfaction, also called Smell and taste (gustation), is an example of chemical senses. The food that we eat and the air that we breathe contain chemicals. Sensory receptors sense these chemicals.

What are the three chemical senses? 

Usually, it’s considered that there are just two chemical senses, Taste and Smell, but there’s also a third one named the Trigeminal chemosensory system. The trigeminal system is also a chemical sense that detects chemicals in the skin. Its chemical Receptor is present in the leather lining oral and nasal cavities. Therefore it’s called cutaneous chemosensation. Overall, there are three chemical senses in living organisms as follows. 

• Taste 
• Smell 
• Trigeminal System

Taste

Taste (gustation) is detected by the chemical Receptor present in the mouth. We usually divide the taste into four basic sensations: sour, sweet, salty, and bitter. But the Japanese found that six different senses come under the category of preference. Umami is the fifth one related to taste sub sensation. Umami sense is due to monosodium glutamate interaction. And the sixth one is associated with taste due to food containing fatty Content. 

So, when we eat food, the molecules present in that food dissolve in saliva (the fluid in our mouth). These molecules interact with taste buds on the tongue, throat, and inside the mouth.

Taste Receptors (Taste Buds)

A group of taste receptor cells containing hair-like extensions that protrude from their center is known as a taste bud. The life cycle of a taste bud is about 10-15 days. Some can be dead before burning the tongue, but it may not severely affect the tongue skin when they die off inside the mouth but a minor irritation on pain. 

How do taste receptor cells detect taste?

So, when the food molecules interact with taste buds, they bind with the taste receptor through hair-like extensions and cause chemical changes. The chemical change in receptor cells results in the signaling of the nerve impulse. Nerves transmit these nerve impulses to the brain for sensory functions, where information is accompanied by the thalamus, medulla, limbic system, and gustatory cortex (nestled beneath the gap between temporal lobes and frontal lobes in the brain) 

Smell 

The second chemical sense related to the chemical perception present in the air is Smell. The Olfactory receptors sense the Smell. When odor molecules interact with receptor cells in the olfactory system, we feel the sense of odor.

Olfactory Receptors

A mucous membrane at the top of the nose or the nasal cavity contains Olfactory receptor cells. These receptors also have minor thin hair-like extensions that allow odorant molecules dispersed in mucus to engage with chemical Receptors upon those extensions. Chemical changes inside receptors cells cause a signal to be delivered to a bulb-like structure called the olfactory bulb. This bulb is present at the base of the frontal lobe from where the Olfactory nerve originates.

How do the olfactory receptor cells detect a Sense of Smell?

When odorant molecules interact with receptors, the message conveyed from the olfactory bulb is delivered to the limbic system and central Olfactory cortex. The sensitivity of the Olfactory System in various species varies dramatically. Dog’s olfactory systems are frequently thought to be considerably superior to our own. And they can still do fantastic work with noses. 

According to data analysis, Dogs may be able to smell harmful dips in malignant tumors and blood glucose levels. Many genes that function for odor receptors are found in a dog’s nasal cavity between 800-1200, comparable to the fewer than 400 found in humans, which may explain their exceptional olfactory abilities. In addition, Pheromones are the chemical message that usually signals the male to female when there’s time to mate with her.

Trigeminal System 

One of the chemical senses that’s rarely known is the Trigeminal Chemosensation system. The Trigeminal System contains receptor cells that are present in the skin of the nose and mouth. They also detect chemicals that interact with skins. That’s why they’re known as cutaneous sensory receptors. When some substances interact with skin receptors present in nasal or mouth areas, nerves create and transmit the nerve impulse to the brain. 

How are the chemical senses different from the non-chemical senses?

One of the main differences between chemical and non-chemical senses is that Chemical senses need chemical receptors to respond. At the same time, others require neurons to send signals to the brain for a response. Due to the involvement of chemical receptors, they show differences from other senses.

What are the chemical senses in psychology?

Psychology says that both smell and taste function together. For example, when we eat food, both olfactory and taste receptor tissues get stimuli from food. Hence, psychology proved that there is an interaction between both senses.

Are smell and taste memory senses?

Both are closely related to memory because the olfactory nerve is connected with the hippocampus. Hippocampus is the functional part of the brain related to memory. For example, when we sense any chemical or perfume, we may recall the memory spent in the past with this odor. So, the relation of the Olfactory System in nasal passages with the brain proves that both sensations are related to memories.

What parts of the brain are involved in processing the chemicals we taste?

Taste Receptors send the signal to the nervous system passing through the spinal cord. This nerve impulse first goes towards the medulla, then the thalamus, and to the limbic system. Afterward, the signal reaches the Gustatory cortex divided into two substructures: the anterior insula and frontal operculum. It is the part of the brain where information about taste is perceived.

What glands control the Sense of Smell?

The glands that control the Smell are the Bowman or olfactory glands. They are found in the olfactory mucosa, where Olfactory information takes place there with the help of a specialized receptor.

Final Thoughts

To sum up, Chemical senses are those senses that contain chemicals and are detected by chemical receptors. Typically, three chemical senses are present in human beings: taste, Smell, and the trigeminal chemical sensation system. So, whenever we smell or taste a portion of food, a chemical present in that molecule interacts with the receptors. Those receptors send signals to nerve endings to produce basic sensations like sweet, salty, and sour, etc.

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