There Is New Information To Think About Taste, Other Senses
September 7, 2020 at 7:23 p.m.
By Max [email protected]
This column about taste was prompted by a recent report published in PLOS Genetics describing a new subset of Type III cells discovered in taste buds. Taste buds employ three types of taste cells: Type I acts as support cells; Type II cells detect bitter, sweet and umami tastes; and Type III cells detect sour and salty flavors. The new subset are broadly responsive and can announce sour stimuli using one signaling pathway, and sweet, bitter and umami stimuli using another.
Umami is a taste we describe as savory, brothy or meaty. It is one of the five fundamental building blocks of flavor.
Attributes
Taste, or gustation, refers to the capability to detect the taste of substances such as food, certain minerals and poisons, etc.
The sense of taste is often confused with the “sense” of flavor, which is a combination of taste and smell perception. Humans receive tastes through sensory organs called taste buds concentrated on the upper surface of the tongue.
There are five basic tastes: sweet, bitter, sour, salty and umami. The sense of taste is well developed at birth and diminishes when we grow older. In the early years, sweet sensations are preferred and as we age the sense of taste changes and differentiates tastes (gustatory stimuli) better.
Like the sense of smell, our gustatory sense serves highly our joy/quality of life but also our protection: It warns us in relation to poisonous things we might ingest. The ability of taste can be decreased through smoking, alcohol, environmental pollution, viruses and bacteria.
Loss
In a recent study published in the journal Nature Medicine, researchers used data from about 18,000 participants who had been tested for SARS-CoV-2 to understand which symptoms were most common in those who had tested positive. They found that loss of taste and smell were reported by most of those tested, about 65%, and that the most predictive group of symptoms was loss of taste, smell, fatigue, persistent cough and loss of appetite.
Respiratory viruses can often lead to temporary or permanent loss of taste or smell. Other than infection by the coronavirus, the most common causes of a loss of the sense of taste are nasal airway problems, upper airway infection, such as sinus infection, tonsillitis or sore throat.
Function
We use our taste system to decide if we are going to consume or reject a potential food item. This is critical for survival, as we need energy to live but also need to avoid potentially toxic compounds. Therefore, it is important to understand how the taste cells in our mouth detect the chemicals in food and send a message to our brain.
Signals from the taste cells form a code that conveys information about the nature of the potential food item to the brain. How this taste coding works is not well understood. Currently, it is thought that taste cells are primarily selective for each taste stimuli and only detect either bitter, sweet, sour, salt or umami (amino acids) compounds.
The recent study mentioned above discovered a new population of taste cells that can detect multiple types of stimuli, including chemicals from different taste qualities. Thus, taste cells can be either selective or generally responsive to stimuli in brain cells that process taste information.
Other Senses
There are a number of references to additional senses to consider together with the five considered traditional.
One major example is the vestibular system. It explains the perception of our body in relation to gravity, movement and balance. The vestibular system measures acceleration, g-force, bodily movements and head position. Examples of the vestibular system in practice include knowing that you are moving when you are in an elevator, knowing whether you are lying down or sitting up and being able to walk along a balance beam.
The other is proprioception, the sense of the relative position of neighboring parts of the body and strength of effort being employed in movement. This sense is important as it lets us know exactly where our body parts are, how we are positioned in space and to plan our movements. Examples of our proprioception in practice include being able to clap our hands together with our eyes closed, write with a pencil and apply with correct pressure and navigate through a narrow space.
Final Thoughts
Some scientists say there are far more senses than those listed in this column, but they disagree on the exact number. Most of those familiar with the matter say there are between 14 and 20, depending on how you define a sense. Perhaps the simplest definition is: a sense is a channel through which your body can observe itself or the outside world.
Max Sherman is a medical writer and pharmacist retired from the medical device industry. He has taught college courses on regulatory and compliance issues at Ivy Tech, Grace College and Butler University. Sherman has an unquenchable thirst for knowledge on all levels. Eclectic Science, the title of his column, touches on famed doctors and scientists, human senses, aging, various diseases, and little-known facts about many species, including their contributions to scientific research. His new book “Science Snippets” is available from Amazon and other book sellers. He can be reached by email at [email protected].
This column about taste was prompted by a recent report published in PLOS Genetics describing a new subset of Type III cells discovered in taste buds. Taste buds employ three types of taste cells: Type I acts as support cells; Type II cells detect bitter, sweet and umami tastes; and Type III cells detect sour and salty flavors. The new subset are broadly responsive and can announce sour stimuli using one signaling pathway, and sweet, bitter and umami stimuli using another.
Umami is a taste we describe as savory, brothy or meaty. It is one of the five fundamental building blocks of flavor.
Attributes
Taste, or gustation, refers to the capability to detect the taste of substances such as food, certain minerals and poisons, etc.
The sense of taste is often confused with the “sense” of flavor, which is a combination of taste and smell perception. Humans receive tastes through sensory organs called taste buds concentrated on the upper surface of the tongue.
There are five basic tastes: sweet, bitter, sour, salty and umami. The sense of taste is well developed at birth and diminishes when we grow older. In the early years, sweet sensations are preferred and as we age the sense of taste changes and differentiates tastes (gustatory stimuli) better.
Like the sense of smell, our gustatory sense serves highly our joy/quality of life but also our protection: It warns us in relation to poisonous things we might ingest. The ability of taste can be decreased through smoking, alcohol, environmental pollution, viruses and bacteria.
Loss
In a recent study published in the journal Nature Medicine, researchers used data from about 18,000 participants who had been tested for SARS-CoV-2 to understand which symptoms were most common in those who had tested positive. They found that loss of taste and smell were reported by most of those tested, about 65%, and that the most predictive group of symptoms was loss of taste, smell, fatigue, persistent cough and loss of appetite.
Respiratory viruses can often lead to temporary or permanent loss of taste or smell. Other than infection by the coronavirus, the most common causes of a loss of the sense of taste are nasal airway problems, upper airway infection, such as sinus infection, tonsillitis or sore throat.
Function
We use our taste system to decide if we are going to consume or reject a potential food item. This is critical for survival, as we need energy to live but also need to avoid potentially toxic compounds. Therefore, it is important to understand how the taste cells in our mouth detect the chemicals in food and send a message to our brain.
Signals from the taste cells form a code that conveys information about the nature of the potential food item to the brain. How this taste coding works is not well understood. Currently, it is thought that taste cells are primarily selective for each taste stimuli and only detect either bitter, sweet, sour, salt or umami (amino acids) compounds.
The recent study mentioned above discovered a new population of taste cells that can detect multiple types of stimuli, including chemicals from different taste qualities. Thus, taste cells can be either selective or generally responsive to stimuli in brain cells that process taste information.
Other Senses
There are a number of references to additional senses to consider together with the five considered traditional.
One major example is the vestibular system. It explains the perception of our body in relation to gravity, movement and balance. The vestibular system measures acceleration, g-force, bodily movements and head position. Examples of the vestibular system in practice include knowing that you are moving when you are in an elevator, knowing whether you are lying down or sitting up and being able to walk along a balance beam.
The other is proprioception, the sense of the relative position of neighboring parts of the body and strength of effort being employed in movement. This sense is important as it lets us know exactly where our body parts are, how we are positioned in space and to plan our movements. Examples of our proprioception in practice include being able to clap our hands together with our eyes closed, write with a pencil and apply with correct pressure and navigate through a narrow space.
Final Thoughts
Some scientists say there are far more senses than those listed in this column, but they disagree on the exact number. Most of those familiar with the matter say there are between 14 and 20, depending on how you define a sense. Perhaps the simplest definition is: a sense is a channel through which your body can observe itself or the outside world.
Max Sherman is a medical writer and pharmacist retired from the medical device industry. He has taught college courses on regulatory and compliance issues at Ivy Tech, Grace College and Butler University. Sherman has an unquenchable thirst for knowledge on all levels. Eclectic Science, the title of his column, touches on famed doctors and scientists, human senses, aging, various diseases, and little-known facts about many species, including their contributions to scientific research. His new book “Science Snippets” is available from Amazon and other book sellers. He can be reached by email at [email protected].
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