Sense of smell and taste.

Sense of taste and our sense of smell allows us to distinguish between junk and even deadly food from tasty and nutritious food. Smell allows animals to recognize the proximity of other animals, or even certain animals among many others. Finally, both senses are closely related to the primitive emotional and behavioral functions of our nervous system.

Taste is mainly a function of the taste buds of the oral cavity, but everyone knows from their own life experience that smell also makes a big contribution to taste. In addition, the texture of food, as perceived by the tactile receptors in the oral cavity, the presence of substances in food that stimulate pain endings, such as pepper, significantly alter the perception of taste. The importance of taste lies in the fact that it allows a person to choose food according to desires, and often in connection with the metabolic needs of body tissues for certain substances.

Not all specific chemical substances that excite different taste buds are known. Psychophysiological and neurophysiological studies have identified at least 13 possible or probable chemical receptors in taste cells. Among them are 2 sodium receptors, 2 potassium, 1 chlorine, 1 adenosine, 1 inosine, 2 receptors for sweet, 2 receptors for bitter, 1 glutamate receptor and 1 receptor for hydrogen ions.

For practical taste analysis The potentials of these receptors are grouped into five main categories called primary taste sensations: sour, salty, sweet, bitter, and yumami.

A person can feel hundreds of different flavors... They are all supposed to be combinations of primary taste in the same way that all the colors we see represent combinations of the three primary colors.

Sour taste... Sour taste is caused by acids, i.e. is associated with the concentration of hydrogen ions, and the intensity of this taste sensation is approximately proportional to the logarithm of the concentration of hydrogen ions. This means that the more acid there is in the food, the stronger the sour sensation.

Salty taste... Salty taste is associated with ionized salts, mainly the concentration of Na + ions. The quality of the taste varies from one salt to the next, as some salts cause other taste sensations in addition to salinity. Salt cations are mainly responsible for the salty feeling, especially Na + ions, but anions also contribute, albeit to a lesser extent.

Sweet taste... Sweet taste is not associated with any one class of chemical. Substances that cause this taste include sugars, glycols, alcohols, aldehydes, ketones, amides, esters, some amino acids, some small proteins, sulfonic acids, halogenated acids, and inorganic lead and beryllium salts. Please note that most of the substances that cause sweet taste are organic. It is particularly interesting that a small change in chemical structure, such as the addition of a simple radical, can often change the taste of a substance from sweet to bitter.

Bitter taste... As with sweet taste, there is no single chemical that causes a bitter taste. Again, almost all bitter tastants are organic. Two specific classes of substances are most likely to produce bitter sensations: (1) long-chain organic substances containing nitrogen; (2) alkaloids. Alkaloids are found in many medicines used in medicine, such as quinine, caffeine, strychnine, and nicotine.

Some substances at first sweet taste, have a bitter aftertaste. This is especially true for saccharin, for example, which makes the substance unpleasant for some people.

Bitter taste high intensity usually causes a person or animal to refuse food. This is undoubtedly an important function of bitter taste, as many of the deadly toxins found in poisonous plants, are alkaloids, and almost all of them have an intensely bitter taste, which usually leads to the rejection of foods containing them.

Yumami taste... Yumami is a Japanese word (meaning "very tasty") that indicates a pleasant mouthfeel that is qualitatively different from sour, salty, sweet, or bitter. Yumami is the main flavor of foods containing L-glutamate, such as meat extracts and aged cheese, and is considered by some physiologists to be a separate, fifth category of primary gustatory stimuli.

Taste receptor for L-glutamate possibly associated with one of the glutamate receptors expressed in the nerve synapses of the brain. However, the exact molecular mechanisms responsible for yumami taste are not yet clear.

Tutorial video of the anatomy of the pathway of the taste analyzer

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Olfactory and gustatory senses

Perception of smells. Smell is an extremely subtle sense. A person can easily distinguish and memorize up to 1000 odors, and an experienced specialist is able to distinguish 10,000 - 17,000 odors. Along with the concept of smell, the terms “aroma” are used to denote a pleasant smell and “bouquet” to characterize a complex aroma ”that develops as a result of enzymatic and chemical processes, for example, when aging wines and cognacs, when ripening rennet cheeses, canned fish types "Sprats" and "Sardines", when fermenting tea, roasting coffee beans, etc.

The olfactory organ is located in the nasal cavity. The olfactory epithelium is located on an area of ​​3 - 5 cm 2, has yellow due to the presence of dye grains in special sensitive cells located in the mucous membrane of the upper part of the septum, nasal vault and other parts of it. The olfactory epithelium, located in the upper part of the nasal cavity, is in direct communication with the oral cavity. Molecules of volatile aromatics found in oral cavity, easily enter the nasal cavity through the nasopharynx.

A variety of smell occurs when the trigeminal nerve is excited, which has many endings in the nasal cavity. The nerves of the pharynx and tongue, the vagus nerve of the larynx and other nerves are poorly excited when exposed to aromatic substances.

The stimulating effect of certain odors on the ability to intensive physical or mental work, as well as the calming effect of certain odors on the nervous and other systems of a person was found.

Over the past 100 years, about 30 different odor hypotheses have been identified, but there is still no scientifically proven theory. The stereo-chemical and membrane hypotheses are more widely known. The latter explains the occurrence of odor by the permeability of the cell membrane to molecules of a volatile substance, but does not substantiate a wide range of perceived olfactory sensations. According to the stereochemical hypothesis, odor recognition depends on the correspondence of the size and shape of the molecules of the aromatic substance to the so-called particle geometry) to certain holes (pores) in the olfactory region of the nose. P. Martin (England) received the Nobel Prize for the hypothesis on the mechanism of the sense of smell. It is based on the interaction of enzymes activated by the molecules of the odoriferous substance with the corresponding coenzymes.

Along with the unresolved difficulties in the theoretical interpretation of the mechanism of smell perception by the olfactory organ, the problem of odor classification remains unresolved. Several classification systems have been proposed, dividing odors into, 7, 9, 10, 11 groups, which, in combination, create existing shades. For example, the classification created by Crocker and Tsnderson (1927) divides all known odors into four groups:

Aromatic-floral (some ketones with a violet scent, as well as a musk scent);

· Acidic (elements of this smell are contained in formic and acetic acids);

· Burning smell (roasted coffee and furfural);

· Caprylic (goat, found in fusel oils, rancid fats, kerosene, gasoline, in the smell of decomposing corpses and animal secretions).

The most widespread was the one developed by Cupid in 1962 ᴦ. a classification that distinguishes seven basic, or primary, odors:

· Camphor (hexachloroethane);

Musky (musk, xylene);

Floral (a-amylpyridine);

Mint (menthol);

· Ether (ethyl ether);

Spicy (formic acid);

Putrid (hydrogen sulfide).

Ways to restore olfactory sensitivity

A glass of water is poured into an enamel pot, 2 drops of peppermint essential oil and a teaspoon of cologne are added to it, and then heated to a boil and breathing over steam for 3 - 5 minutes, making forced long breaths throughout the procedure. The course of treatment is 6 - 8 procedures daily or every other day.

Pour a glass of water into an enamel pot, bring it to a boil and add 10-12 drops lemon juice and 1 drop of lavender or peppermint essential oil. Breathe over the steam for 3 - 5 minutes each nostril, making forced breaths. The course of treatment is 10 procedures daily or every other day.

A coin in denominations of 1 or 2 rubles. smeared with honey, applied to the very middle of the back of the nose and fixed with a plaster. Better yet, use an old copper coin. You need to hold the coin for at least 30 minutes daily. Often, after 15 - 20 procedures, the sense of smell is fully restored.

Add 10 drops of lemon juice and cologne to a glass of water heated to 50 "C. Gauze or cotton cloth is soaked in this water and applied to the entire surface of the nose for 5 - 7 minutes. The course of treatment is 10 procedures daily.

Vietnamese balm "Golden Star" is left in the sun for several hours in a closed jar, then rubbed into the bridge of the nose and in the middle of the forehead. The course of treatment is 7-10 procedures daily.

It is helpful to learn to tense and relax your nose muscles. This exercise restores the sense of smell well. You need to keep the muscles tense or relaxed for at least a minute. It is extremely important to do the exercise every day for 10 minutes.

Warming up with a blue lamp has a positive effect on hyposmia. You can also use a conventional 40 W bulb. Put on your sun glasses, take off with table lamp lampshade, tilt your head back so that the light falls into the nasal cavity. The distance from the lamp to the nasal cavity should be no more than 25 cm. Carry out the procedure for 10 - 15 minutes daily or every other day for a week.

The well-known procedure according to the yoga system - drawing in warm salted water by the nose - also helps to improve the sense of smell. On a glass of warm boiled water add salt on the tip of a knife. Closing one nostril with a finger, slowly draw in water from the open nostril until it is in the throat. Then the water is spit out. Do the same with the other nostril. You can release water not through the mouth, but through the nose. It is advisable to use all the water poured. The course of treatment is at least 10 procedures.

The described procedures can be varied as desired. Despite their simplicity, they are great for improving the sense of smell.

Taste sensations... Smell perception is inextricably linked to the sense of taste. In analytical terminology, there are four basic types of taste:

salty- a sensation for which sodium chloride solution is a typical taste stimulus;

sweet- a sensation for which a typical taste stimulus is an aqueous solution of sucrose;

bitter- a sensation for which typical taste stimuli are aqueous solutions of caffeine, quinine and some other alkaloids;

sour- a sensation for which typical taste stimuli are aqueous solutions of tartaric, citric and a number of other acids.

Other types and shades of tastes are complex sensations of these tastes. The term “stimulus” is recommended to denote a substance or electrophysical effect that causes a gustatory sensation when interacting with chemoreceptors.

V recent times alkaline and astringent are added to the four types of flavors. Alkaline occurs from chemical irritation of the oral mucosa and is not caused by specific taste buds. A typical stimulus for the alkaline taste is an aqueous solution of sodium bicarbonate, and for an astringent taste, an aqueous solution of tannins.

Taste sensations are perceived at different rates. The most rapidly arising sensation of salty taste, then sweet, sour, much slower - bitter. This is due to the uneven distribution of taste buds.

The outer perceiving part of the human taste organ is represented by taste buds, which are located in the so-called papillae (kidneys) of the tongue. Individual bulbs are also scattered in the mucous membrane of the soft palate, the posterior wall of the epiglottis, and even on the lateral walls of the larynx. The total number of taste buds can reach several thousand.

Taste receptors are susceptible to rapid death and neoplasm. With age, the number of taste buds can decrease by two to three times, which leads to a strong decrease in taste.

Taste receptors on the tongue have a pronounced specificity. At the very tip of the tongue and along the edges there are large mushroom papillae, each of which has 8-10 bulbs. The sweet taste is most felt at the end of the tongue, salty at the edges of the front of the tongue, and sour at the edges of the back of the tongue. At the base of the tongue are grooved papillae, each of which has 100 - 150 taste buds that perceive a bitter taste.

The organ of taste (tongue) of a person is a chemical analyzer. The mechanism of its functioning is that the substance, dissolved in water or in saliva, penetrates through the gustatory pores to the bulbs, in which chemical irritations are converted into nerve impulses that are transmitted along nerve fibers to the central nervous system.

The chemical receptor on the tongue is protein. Immersion of the tongue in the solution is usually not sufficient to induce a taste sensation. In this case, there is a feeling of touch, sometimes cold. The perception of taste occurs better when the tongue touches the walls of the vessel, and the residence of the tongue to the palate facilitates the penetration of the sample solution into the pores of the taste buds of the bulbs

There is no generally accepted theory of taste, since the mechanism of functioning of the cells of the taste organ is not well understood. The existing hypotheses are based on physicochemical, chemical and enzymatic prerequisites. A certain relationship has been established between the chemical nature of the flavoring agent and the sensation of taste it causes. But substances of different structures can have the same taste and, on the contrary, substances of the same chemical. natures have different tastes. Not only sugars are felt sweet, but also many amino acids, saccharin. The protein tuamatin, which has a molecular weight of 22 thousand, consists of 207 amino acid residues and is 8 thousand times sweeter than sucrose, has been isolated from plant raw materials.

With the exception of sodium chloride, which has a purely salty taste, all other salts have a more or less mixed taste. The quality of the salty taste is mainly determined by the anion, and the intensity of the taste is determined by the cation. At a sodium chloride concentration (mol / l) of 0.009, the solution has no taste, within the range of 0.01 - 0.03, the solutions have a sweet taste of varying intensity, 0.04 and above - salty. At a concentration of potassium chloride (mol / l) 0.009 - 0.02, solutions have a sweet taste, 0.03 - 0.04 - bitter, 0.05 - 0.1 - bitter and salty, and starting from 0.2 and higher - salty, bitter and sour. Potassium iodide has a bitter taste, potassium bromide is salty-bitter, calcium chloride is bitter.

The intensity of the organoleptic sensation of table salt in fish is 0.4 - 1% lower than in a solution of the corresponding concentration.

Sour taste is caused by inorganic acids, as well as organic acids and their salts. Sour taste depends mainly on the concentration of hydrogen ions. For organic acids, the intensity of the sour taste is greater than expected at the corresponding concentration of hydrogen ions.

Typical bitter substances are the alkaloids quinine and caffeine. Many mineral salts, most of nitro compounds, some amino acids, peptides, phenolic components of smoke and smoked meats have a bitter taste.

Threshold concentrations of compounds in aqueous solutions and products do not coincide, and this must be taken into account in technological developments. Some substances can mask or, conversely, enhance the taste of other food components. Mixing base flavors, as well as changing their intensity, can cause such complex complex phenomena as rivalry of tastes, compensation of tastes, disappearance of repeated tastes, contrasting tastes, and other sensory sensations.

Influence of factors on taste and smell.Adaptation is the adaptability of the organs of taste and smell, which consists in a decrease in their sensitivity caused by prolonged exposure to a stimulus (continuous or repetitive) of the same quality and constant intensity. When the stimulus stops acting, then there is a restoration of gustatory and olfactory sensitivity. In contrast to sight, the organs of smell and taste are subject to rapid adaptation. The adaptation to odors in humans is more pronounced than To tastes. In particular, a person usually does not smell his clothes, his home, his own body.

G.A. Wux gives information about the development of adaptation of the organ of smell to odors. So, the time, which is extremely important for adaptation to the smell of certain substances, will be as follows (min): iodine solution - 4, garlic - 45 or more, camphor - 2 or more, phenol - 9 or more, coumarin - 1 - 2, essential oils- 2 - 9.2, cologne - 7 - 12.

In some cases, with repeated exposure to very weak stimuli arriving sequentially one after the other v significant periods of time, the sensibility of the organ of taste or smell can increase and persist for a long time. This phenomenon is usually called sensitization.

Increasing sensitivity is achieved with the help of stimuli, the intensity of which is equal to the threshold, as well as due to the activity of the taster himself. The interval between repeated stimulus exposure depends on the type of stimulus and the sensory abilities of the tasters. For example, for hearing and vision, this interval should be 3 minutes for one taster and 1.5 minutes for another. Sensitization is characterized by the persistence of maintaining this property.

G.A. Vuks notes that experimentally induced sensitization of smell can be retained for 7 - 22 days and then recover from a few workouts. To increase the sensitivity to a certain stimulus by an average of 60 - 70%, you need to feel its effect on the corresponding sensory analyzer for 30 - 35 minutes with an interval of 1 - 2 minutes.

sensitization in relation to the code smell entails a slight increase in sensitivity to other odors.

Sensitization to red tends to reduce sensitivity to green, and in some cases to yellow. Sensitization to green color results in decreased sensitivity to red, ᴛ.ᴇ. along with the selectivity of the obbl, it is possible to simultaneously change the thresholds of other colors. This phenomenon is typical of taste: sensitization of one of the basic tastes affects other basic tastes. However, these patterns have not been fully studied. For example, sensitization to bitter has been found to simultaneously increase sensitivity to sweet taste, and sensitization to sweet taste improves sensitivity to bitter taste. Salty sensitization can decrease sensitivity to sweets in some tasters and increase it in others.

According to the profile of the taster, an increased sensitivity to certain chemicals can be observed. There are cases when a laboratory assistant performing a chemical analysis of the mass fraction of table salt in a food product, over time, could sensibly accurately determine the salinity of the product. Similar cases are known in the alcoholic beverage industry, when the taster, thanks to the sensitization of the taste and smell analyzers, determines the alcohol content in beverages with high accuracy. In the perfume industry, tasters are selectively sensitive To certain smells.

Individual susceptibility to odors and tastes. Some people have a lack of smell in relation to either all odorous substances, or to one substance, or to a group of substances. This phenomenon is usually called anosmia and was found relative to butyric acid, trimethylamine, hydrocyanic acid, skatole alcohol and a number of other substances.

Anosmia is more common in men (about 20%), less often in women (about 5%). It is believed to be inherited by descendants of the same sex. Anosmia maintains a normal sense of smell for many common odors. In most cases, a person does not realize that he has a partial lack of smell. This phenomenon is extremely important in the selection of specialists in sensory analysis.

Loss of smell must be due to injury from illness, traffic accidents, or medication. Diseases of the nasopharynx often lead to a decrease in the function of smell: chronic rhinitis and chronic inflammatory diseases of the paranasal sinuses - sinusitis, frontal sinusitis, sphenoiditis, rhinovirus infections. The sense of smell can be reduced due to adenoids, polyps in the nose, curvature of the nasal septum.

Cases of decreased olfactory sensitivity to all or individual odorous substances are not uncommon. This phenomenon is usually called hyposmia. Much less often there is an unusually high human olfactory sensitivity either to all odorous substances, or to one substance, or To group of substances. This phenomenon is usually called hyperosmia.

Hallucinations of the sense of smell are also possible, manifested in the fact that a person senses a smell, which in reality does not exist. This type of damage to the sense of smell is usually called spontaneous sense of smell or by parosmia.

Lack of gustatory sensitivity to either all flavors, or To to one substance, or to a group of substances, it is customary to call ageusia. Reduced gustatory sensitivity to all or individual substances is usually called hypogeusia, and an unusually high sensitivity - hypergeusia. The perverse ability to feel a taste that is not characteristic of a given substance or group of substances is denoted by the term parageusia.

Scientists believe that the behavior of the taster can be predicted based on the type of physique. It is noted that tasters with a thin and fragile body structure (leptosomics) have twice as many taste aversions as full and squat tasters (picnics).

The results of studies on the influence of gender, age and pH of saliva on the taste sensitivity levels of the taster are ambiguous. It was found that the pH values ​​of saliva correlate with the taster's susceptibility to bitter solutions and bitter taste of food products. After tasting, the acidic reaction of saliva, as a rule, decreases, and its alkalinity increases.

Several studies have compared the levels of taste sensitivity with the social status and cultural level of the tasters tested. Thus, in groups with low characteristics of status and culture, high thresholds for recognition of basic tastes were observed. The Japanese are considered the most subtle in terms of taste perception. It was found that genetic taste analyzer disorders are more common among Europeans and only 6-10% of such disorders are observed in African blacks.

Individual differences in the thresholds of sensitivity in humans are significant: for the sense of smell 1000: 1, for the organ of taste 64: 1. A small (not exactly accounted for) part of the population is completely devoid of sensitivity to taste or smell.

Influence of age. WITH with age, the sensitivity to odors decreases in a logarithmic sequence. This extends not only to the sense of smell, but also to sight, hearing, taste and touch. It is believed that a person loses up to 50% of visual acuity and hearing by 13 - 15 years, the ability to perceive smell and taste - by 22 - 29, tactile sensitivity - by 60 years. The age factor is not decisive. Taking into account the dependence on natural data, lifestyle, nutrition, habits, nature of work, fitness of sensory organs with age, a person may increase the sensitivity of smell, taste, touch, much less often - hearing and vision.

Smell memory and representation - it is the ability of a person to recognize those smells with which he previously had to meet, ᴛ.ᴇ. memorize and recognize a known smell. Usually, a person is able to distinguish from several hundred to several thousand different smells. Qualified tasters must be able to recognize at least 10,000 odors. Experts develop their abilities through exercises and can distinguish up to 17 thousand varieties of smell. The ability to remember odors varies greatly among humans. Masking odors are cases of suppression of one odor by another. If two or three odors act on the olfactory organ at the same time, it may happen that none of them will show its real properties, and the perceived sense of smell will be vague or not perceived at all.

Compensation for odors and tastes. Compensation is characterized by an increase, decrease or disappearance of the sensation caused by the main taste or smell, and is associated with the presence of small amounts of a substance of a different taste or smell. Distinguish between positive and negative compensation. In the first case, the main taste or smell is enhanced by the influence of another taste or smell, in the second, the main sensation is weakened.

For example, fructose turns out to be sweeter in acidic environments, and glucose feels less sweet with increasing acidity. The palatability of sugar mixtures is not a simple summation of the sweetness intensities of the components. Typically, the sugar mixture is less sweet than the calculated sum of the ingredients.

With the simultaneous exposure to two different taste impulses, the feeling of a weaker one may disappear. Salty, sweet, sour tastes easily disappear.

When the smells of two chemically non-reacting substances are mixed with each other, a mutual weakening of these smells may appear, ᴛ.ᴇ. their mutual compensation. Discovered a large number of odorous substances, the odors of which are mutually compensated.

It is not allowed to suppress defamatory odors and tastes in food products that characterize negative signs of quality (for example, when using stale raw materials, fats with signs of oxidation, components with defamatory odors, etc.).

Flavoring modifications. A tropical plant is known as a sweet taste inhibitor Gymnema sylvestre, ĸᴏᴛᴏᴩᴏᴇ grows in South India, Ceylon and the tropics of West Africa. Fruit of another tropical plant Miracle fruit modify the sour taste. For example, lemons acquire the taste of sweet and sour oranges. The flavor modification effect lasts for 30-60 minutes. Fruit properties Miracle fruit used in winemaking to soften the sour taste of wines, as well as in the bakery and confectionery industry.

Secondary, or residual, the taste appears after the product has been tasted characteristic taste... Aftertaste usually reduces the consumer value of the product. The appearance of a long-lasting bitter secondary taste is characteristic of fat rancidity.

Flavoring contrast can be a source of error in sensory tests. For example, ordinary water, especially distilled water, seems sweetish if a salty taste is felt before tasting it. A sour taste seems more sour and even unpleasant if it is preceded by a sweet sensation. The phenomenon of taste contrast can distort the results of evaluations of aged wines if sweeter wines were tasted before them. For the same reason, you should not evaluate light-salted products after strong or medium-salted products. Taste contrast is extremely important to consider when determining the order of submission of samples for tasting.

Taste illusions. L. Bartoshchuk found that after tasting the artichoke, clear water feels sweet.

Concept taste harmony characterizes the desirability of sensations and is associated with the compatibility of different tastes. Sweet and sour, salty and sweet harmonize well, it is more difficult to get a harmony of bitter and sweet, it is almost impossible to combine bitter and salty, as well as bitter and sour tastes. Taste harmony develops during the maturation of wines and canned food. Knowledge of technology, organoleptic laws and experience with food products contribute to the creation of taste harmony.

Influence of color on taste. It is noted that red solutions are perceived to be sweeter than colorless sweet solutions of the same concentration. Yellow and light green colors increase the subjective acid rating. Experiments at the University of Tartu have shown that soft drinks are best at quenching thirst when they are light green in color. Complex associations often arise between color, taste and smell.

For example, dark green increases the intensity of taste and smell, yellow gives a denser smelling sensation, and red and light green makes odors easier to perceive. Blue colors different shades cause sensations of a bitter taste and unpleasant technical nuances in the smell. G.A. Vuks has compiled a semantic map, which can be used to describe the smell and taste of different food products. In particular, the taste of raspberry jam is described in terms of warm, heavy, soft, etc.

The influence of external factors. The impressionability of smell and other sensory perceptions changes under the influence of external conditions. The degree of air purification, temperature, relative humidity air, room illumination; for example, in an odorless (deodorized) room, the sensitivity of the sense of smell increases by 25%. So, as the temperature rises, the intensity of the smell increases. The optimum temperature is 37 - 38 "C. A further increase in temperature does not increase the intensity of the odor, but, on the contrary, decreases it. Temperature fluctuations in the odorimetric laboratory cause significant errors in the results. High relative humidity favors better perception of odors. on the general state of the central nervous system and, indirectly, on the human sense of smell.

Other factors also affect the taste and smell of tasters: for example, the shape of the food product - the state of hunger and satiety, associations, personal motives and authorities.

Olfactory and gustatory sensations - concept and types. Classification and features of the category "Olfactory and taste sensations" 2017, 2018.

The sense of taste is associated with irritation of not only chemical, but also mechanical, temperature and even pain receptors of the oral mucosa, as well as olfactory receptors. The gustatory analyzer determines the formation of gustatory sensations and is a reflexogenic zone. With the help of the taste analyzer, various qualities of taste sensations, the strength of sensations, which depends not only on the strength of irritation, but also on the functional state of the body, are assessed.

Structural and functional characteristics of the taste analyzer.

Peripheral department. Taste receptors (taste cells with microvilli) are secondary receptors; they are an element of taste buds, which also include supporting and basal cells. The taste buds contain cells containing serotonin and cells that form histamine. These and other substances play a role in shaping the sense of taste. Individual taste buds are polymodal formations, as they can perceive various types of taste stimuli. Taste buds in the form of separate inclusions are located on the back of the pharynx, soft palate, tonsils, larynx, epiglottis and are also part of the taste buds of the tongue as an organ of taste.

The peripheral part of the taste analyzer is represented by taste buds, which are located mainly in the papillae of the tongue. Taste cells are dotted at their end with microvilli, which are also called taste hairs. They come to the surface of the tongue through the gustatory pores.

The taste cell has a large number of synapses that form the fibers of the tympanic string and glossopharyngeal nerve. The fibers of the tympanic string (a branch of the lingual nerve) fit all the mushroom papillae, and the fibers of the glossopharyngeal nerve - to the grooved and leaf-shaped. The cortical end of the gustatory analyzer is located in the hippocampus, parahippocampal gyrus, and in the lower part of the posterior central gyrus.

Taste cells continually divide and die continually. The replacement of cells located in the front of the tongue, where they lie more superficially, occurs especially quickly. Replacement of taste bud cells is accompanied by the formation of new synaptic structures

Conducting department. Inside the taste bud are nerve fibers that form receptor-afferent synapses. Taste buds of different areas of the oral cavity receive nerve fibers from different nerves: taste buds of the anterior two-thirds of the tongue - from the drum string, which is part of the facial nerve; the kidneys of the posterior third of the tongue, as well as the soft and hard palate, tonsils - from the glossoglossal nerve; taste buds, located in the region of the pharynx, epiglottis and larynx, from the superior peglottic nerve, which is part of the vagus nerve.

These nerve fibers are the peripheral processes of bipolar neurons located in the corresponding sensory ganglia, representing the first neuron of the conduction section of the gustatory analyzer. The central processes of these cells are part of a single bundle of the medulla oblongata, the nuclei of which represent the second neuron. From here, the nerve fibers in the medial loop approach the optic hillock (third neuron).

Central department. The processes of thalamic neurons go to the cerebral cortex (fourth neuron). The central, or cortical, department of the gustatory analyzer is localized in the lower part of the somatosensory cortex in the region of the tongue. Most of the neurons in this area are multimodal, that is, they respond not only to gustatory, but also to temperature, mechanical and nociceptive stimuli. It is characteristic of the gustatory sensory system that each taste bud has not only afferent, but also efferent nerve fibers that approach taste cells from the central nervous system, which ensures that the taste analyzer is included in the integral activity of the body.

The mechanism of gustatory perception. For a gustatory sensation to arise, the irritant must be in a dissolved state. A sweet or bitter flavoring substance that dissolves into molecules in saliva penetrates into the pores of taste buds, interacts with the glycocalyx and is adsorbed on the cell membrane of the microvilli, into which “sweet-feeling” or “bitter-sensitive” receptor proteins are embedded. When exposed to salty or sour flavors, the concentration of electrolytes around the taste cell changes. In all cases, the permeability of the cell membrane of microvilli increases, sodium ions move into the cell, depolarization of the membrane occurs and the formation of a receptor potential, which spreads both along the membrane and along the microtubular system of the taste cell to its base. At this time, a mediator (acetylcholine, serotonin, and, possibly, hormone-like substances of a protein nature) is formed in the taste cell, which in the receptor-afferent synapse leads to the emergence of a generator potential, and then an action potential in the extrasynaptic parts of the afferent nerve fiber.

Perception of gustatory stimuli. Microvilli of taste cells are formations that directly perceive the taste stimulus. The membrane potential of taste cells ranges from -30 to -50 mV. Under the action of gustatory stimuli, a receptor potential of 15 to 40 mV arises. It is a depolarization of the surface of the taste cell, which is the cause of the appearance of a generator potential in the fibers of the tympanic string and glossopharyngeal nerve, which, when a critical level is reached, turns into propagating impulses. From the receptor cell, excitation is transmitted through the synapse to the nerve fiber with the help of acetylcholine. Some substances, such as CaCl2, quinine, heavy metal salts, cause not primary depolarization, but primary hyperpolarization. Its occurrence is associated with the implementation of negative rejected reactions. In this case, no propagating impulses arise.

Unlike olfactory sensations, gustatory sensations can easily be combined into groups based on similar characteristics. There are four main taste sensations - sweet, bitter, sour and salty, which in their combinations can give various shades of taste.

The sensation of sweetness is caused by carbohydrates contained in food substances (diatomic and polyhydric alcohols, monosaccharides, etc.); the sensation of bitter - by acting on the taste buds of various alkaloids; the feeling of sourness arises from the action of various acids dissolved in water; the salty sensation is caused by table salt (sodium chloride) and other chlorine compounds.

In its Everyday life a person often encounters such an incident as a violation of taste (hypogeusia).

It can be short-term (for example, you put too hot food in your mouth and you stop feeling the taste for some time) or long-term - this may be a consequence of deeper disturbances in the human body, or one of the symptoms of a serious illness.

ICD-10 code

R43 Disorders of smell and taste

Causes of taste disturbance

Such a diagnosis is made to the patient in the case when the patient is not able to ascertain the taste of any product:

• If the damage has affected the taste buds. Doctors attribute this pathology to transport losses.
• If the pathology has damaged the receptor cells. Physicians categorize sensory impairments.
• Damage to taste caused by an afferent nerve pathology or a malfunction of the central taste analyzer department. This pathology can be attributed to neural changes.

What are the reasons for the violation of taste:

• Facial nerve, complete or partial paralysis. This pathology is characterized by loss of taste at the tip of the tongue, paralysis of the facial muscles. The affected part of the face looks like a frozen, distorted mask. Paralysis leads to increased salivation and tearing, the blinking process is difficult.
• Craniocerebral lesion. As a result of the trauma, the integrity of the cranial nerve was apparently disrupted. In this case, the patient finds it difficult to differentiate complex flavoring compositions, while the basic tastes (sweet, sour, salty and bitter) are normally distinguished by the patient. Other symptoms of this pathology include bleeding from the nasal cavity, nausea and dizziness, headaches and visual impairment.
• Colds... Quite often, this common disease is accompanied by a blockage of the sense of smell. And also there is edema of the nasopharyngeal region, temperature, decreased vitality, chills and aches, cough.
• Cancer in the oral cavity. Approximately half of cases of lesions of the oral cavity with a tumor occur in the posterolateral region of the tongue, which, most often, leads to necrosis of the taste buds. And as a result - taste disturbance. With this disease, speech is also impaired, the process of chewing food becomes problematic, an unpleasant odor appears that spreads from the mouth.
• Geographic language. This term was coined by doctors for inflammation of the papillae of the tongue, which is manifested by hyperemic spots of various shapes covering the tongue. The spotted pattern is somewhat reminiscent of a geographic map.
• Candidiasis or thrush. This disease is manifested by a fungal infection of the oral cavity and is expressed by the appearance of cream and milky spots on the palate and tongue. The patient feels a burning sensation, appear pain, there is a violation of taste perception.
• Sjogren's Syndrome. This disease has genetic roots. Symptoms of its manifestation are disturbances in the functioning of the secreting glands, such as sweat, salivary, lacrimal. Blocking salivation leads to drying out of the oral mucosa, impaired taste perception, and periodic infection of the cavity. A similar dryness occurs on the cornea of ​​the eye. The symptoms of this disease also include nosebleeds, an increase in the size of the salivary and lacrimal glands, dry cough, swelling of the throat and others.
• Acute viral hepatitis. The symptom that precedes the manifestation of other signs of this disease is jaundice. At the same time, there is a curvature of olfactory perception, nausea and vomiting appear, appetite disappears, general weakness, muscle and headaches, joint pains and others intensify.
• Consequences of radiation therapy. Having received a dose of radiation in the neck and head during the treatment of this terrible disease, the patient also acquires a bunch of pathologies and complications. Some of them are taste disturbances, dry mouth.
• Thalamic syndrome. This pathology carries with it changes in the normal functioning of the thalamus, which quite often entails such a violation as a distortion of taste perception. The primary sign of a developing disease and a signal bell is a superficial and deep enough loss of skin sensitivity with the manifestation of partial paralysis and significant loss of vision. In the future, sensitivity can recover and develop into hypersensitivity, for example, to pain.
• Zinc deficiency. Laboratory studies often show that patients with taste disturbances lack this chemical element, which indicates its significant role in preventing hypogeusia. Zinc deficiency leads to a failure in the sense of smell. The patient may begin to perceive unpleasant repulsive odors as a wonderful scent. Other symptoms of an element deficiency include hair loss, increased nail brittleness, and a volumetric enlargement of the spleen and liver.
• Lack of vitamin B12. This seemingly insignificant deviation in the mineral content of the body can provoke not only hypogeusia (taste disturbance), but also disruptions in the sense of smell, as well as weight loss, up to anorexia, tongue edema, impaired coordination of movement, shortness of breath, and others.
• Medications... There are many medications that can, in the process of taking them, affect the change in taste preferences. Some of them are: penicillin, ampicillin, captopril, clarithromycin, tetracycline (antibiotics), phenytoin, carbamazepine (anticonvulsants), clomipramine, amitriptyline, nortriptyline (antidepressants), loratadine, horfeniramine, pseudo-ephedrine medications ), captopril, diacarb, nitroglycerin, nifedipine (antihypertensive (pressure), cardiotropic (cardiac)) and many others. There are hundreds of them, and before you start taking this or that drug, you should re-read the instructions for use and side effects.
• Ear surgery. Hypogeusia can develop as a result of the unprofessional carrying out of this operation or in connection with the physiological characteristics of the body.
• Long-term smoking (especially pipe smoking). Nicotine can lead to partial atrophy of taste buds or distortion of their work.
• Injuries to the mouth, nose or head. Any trauma is fraught with consequences. One of these consequences can be a violation of taste and smell.
• If hypogeus is suspected in little child, do not jump to conclusions. In fact, it may turn out that the baby simply does not want to eat or does not want to eat this particular product.

Symptoms of Taste Disorder

Before moving on to a more detailed acquaintance with this disease, let's define the terminology. On the basis of clinical studies and based on patient complaints, doctors spread the symptoms of taste disturbances into certain categories:

• General ageusia is a problem in recognizing simple basic tastes (sweet, bitter, salty, sour).
• Selective ageusia is the difficulty in recognizing certain flavors.
• Ageusia specific - reduced sensitivity of taste to certain substances.
• General hypogeusia is a violation of taste sensitivity, which manifests itself in the case of all substances.
• Selective hypogeusia is a taste disorder that affects certain substances.
• Dysgeusia - perverted manifestations in taste preferences. This is either an incorrect taste sensation of a particular substance (sour and bitter tastes are often confused). Or somatically imposed perception of tastes against the background of absent gustatory stimuli. Dysgeusia can develop both on a semantic basis and in pathology at a physiological or pathophysiological level.

Forms

Impaired sense of smell and taste

It is quite rare when, with a particular disease, a patient is diagnosed with either only a violation of taste, or, alone, a violation of the sense of smell. This is rather an exception to the rule. More often, in most diagnosed cases, impairment of smell and taste go hand in hand. Therefore, if a patient complains of a loss of taste, the attending physician must also examine the sense of smell.

Such an interconnected violation rarely leads to disability, does not pose a threat to life, but a violation of taste and smell can greatly reduce the quality of social life. Often, these changes, especially in the elderly, can lead to lethargy, impaired appetite, and ultimately exhaustion. Loss of smell can also lead to dangerous situations. For example, the patient simply will not feel the odorant (aromatized fragrance), which is specially mixed with natural gas. As a result, it does not recognize a gas leak, which can lead to tragedy.

Therefore, before stating the manifested symptoms as harmless, the attending physician must exclude deep, systemic diseases. Since hyperosmia (increased sensitivity to odors) can manifest itself as one of the symptoms of neurotic diseases, and dysosmia (a perverse sense of smell) - with the infectious genesis of the disease.

Adequate perception of taste in humans occurs when, in the process of recognition, all groups of receptors work: both facial and glossopharyngeal, as well as receptors of the vagus nerves. If at least one of these groups, due to reasons, drops out of the examination, the person gets a violation of taste.

Taste receptors are scattered over the surface of the oral cavity: these are the palate, and tongue, pharynx and pharynx. When they get irritated, they send a signal to the brain, and already the brain cells recognize this signal as taste. Each group of receptors is "responsible" for one of the main tastes (salty, bitter, sweet, sour) and only in a complex working together, they are able to recognize the nuances and subtleties of flavors.

For reasons of a non-pathological nature in violation of taste and smell, doctors include age-related changes (a decrease in the number of taste buds), smoking, which dries the mucous membrane (taste is better recognized in a liquid medium).

Diagnosis of taste disorders

Before proceeding with the diagnosis, it is necessary to clearly cut off the case when the patient not only finds it difficult to determine the taste of the product, but also suffers from a pathology of smell.

First of all, a specialist tests taste sensitivity throughout the mouth, determining its threshold of manifestation. The patient is asked in turn to determine the taste of citric acid (sour), table salt (salty), sugar (sweet) and quinine hydrochloride (bitter). The test results are clinical picture and the scale of the defeat.

The qualitative threshold of sensations in certain lingual zones is checked by applying a few drops of the solution to individual areas of the oral cavity. The patient swallows and shares his feelings, but the characteristics are given differentiated, for each site separately.

To date, such research methods as electrometric ones have appeared, but they do not paint a sufficiently clear reliable picture of perception, therefore, the diagnosis of taste disturbances is carried out in the old fashioned way, by clinical taste tests.

As in the case of the pathology of smell, in case of taste disturbance, at the moment, there are no exact methods that can categorically differentiate the causes of a sensory, transport or neural nature. In order for the doctor to be able to more specifically determine the cause of the neurological disorder, it is necessary to localize the site of the lesion as accurately as possible. Anamnesis of the patient also provides important information for the attending physician. It is necessary to exclude genetically transmitted endocrine diseases.

It is necessary to investigate and side effect medicines if the patient is undergoing treatment for another disease. In this case, the treating doctor will either prescribe another drug of the same action, or change the dosage of the first one.

Computed tomography is also performed. It will provide a clinical picture of the condition of the sinuses and medulla. It is necessary to exclude or confirm the presence of systemic diseases. Diagnostics of the oral cavity will help determine the possible local causes (diseases) that can lead to a violation of taste: a malfunction in the functioning of the salivary glands, otitis media, prosthetics of the teeth of the upper jaw, and others.

The doctor is also interested in the presence of a patient with craniocerebral trauma, laser irradiation of the head and neck region, diseases associated with inflammatory processes of the central nervous system and cranial nerves.

The attending physician also establishes the chronology of the onset of the disease, injury or surgery with the appearance of a taste disorder. It is necessary to understand if the patient has contact with toxic chemicals?

In women, important information is the onset of menopause or recent pregnancy.

Laboratory tests are also carried out. They are able (a detailed blood test) to give an answer whether there are foci of infectious lesions or manifestations of an allergic nature in the patient's body, anemia, blood sugar levels ( diabetes). Carrying out special tests will allow you to recognize hepatic or renal pathology. Etc.

If there are any suspicions, the attending physician directs his patient for a consultation with a narrowly focused specialist: an otolaryngologist, dentist, endocrinologist, neurologist, and so on. And in the presence of a traumatic brain injury, the patient undergoes X-rays, as well as CT or MRI of the head, which will help to identify intracranial changes or disorders of the cranial nerves.

If no obvious reasons for the violation of taste can be found, a second diagnosis is carried out after two to four weeks.

Taste disorders treatment

First of all, the treatment of a taste disorder is the elimination of the cause of its occurrence, that is, it is a set of measures that lead to the arrest or complete eradication of the disease that led to this pathology

Treatment can be started not after the doctor has ascertained taste disturbances, but after the source and cause of this pathology has been fully established.

If the cause of taste disturbances is a drug that the patient takes during treatment, then the attending physician, after the patient's complaints, either change the drug to another, of the same group, or change the dosage of the first one, if it is impossible to replace it.

In any case, if the problem exists and has not yet been resolved, or the composition of the secretion has undergone a change, artificial saliva is attributed.

• "Hyposalix"

This medicinal product is used to moisturize the oral cavity, which will completely or partially restore the arisen taste disturbance.

The solution is sprayed into the mouth while the patient is sitting or standing. The medical cartridge is pointed alternately at inner side then one cheek, then the other. Spraying is carried out with a single press. The number of daily repetitions is six to eight times. The time frame is not limited, but is sprayed as needed - if the patient begins to feel dry mouth. This drug is not toxic, it can be safely used by both pregnant women and small children, there are no contraindications for lactation.

If the source of the problem is bacterial and fungal diseases- the treatment protocol for such a patient will consist of drugs that can inhibit the harmful pathogenic flora.

• Erythromycin

Daily dose of the drug:

• for newborns under the age of three months - 20-40 mg;
• babies from four months to 18 years old - 30-50 mg per kilogram of the child's weight (in two to four doses);
• for adults and adolescents who crossed the threshold at the age of 14 - 250 - 500 mg (one-time), repeated intake no earlier than 6 hours later, the daily dosage can be increased to 1-2 g, and in case of a severe form of the disease, up to 4 g.

When taking this drug, some side deviations may occur: nausea, vomiting, dysbiosis and diarrhea, impaired liver and pancreas function, and others. This drug is contraindicated during lactation, since it perfectly penetrates into breast milk and with it can enter the body of a newborn. As well as increased hypersensitivity to substances that are part of the medication.

• Captopril

If the cause of taste disturbance is a malfunction of the kidney function, the doctor prescribes a daily dose (for a non-severe form of the disease) of 75-100 mg. With more severe manifestations of the disease, the daily dose is initially reduced to 12.5-25 mg and, only after a while, the attending physician gradually begins to increase the amount of the drug. For elderly people, the dosage by the doctor is selected individually, starting from the figure of 6.25 mg, and it is necessary to try to keep it at this level. Reception is carried out twice a day.

This drug is not recommended for use if there is an intolerance to one or more of the components that make up the drug, as well as with pronounced disorders in the liver and kidneys. Very carefully, only under the supervision of a doctor, to take to persons with diseases. of cardio-vascular system... Not recommended for children under the age of 18, as well as for pregnant and lactating mothers.

• Methicillin

Or the scientific name is methicillin sodium salt. It is only prescribed intramuscularly.

A solution of the drug is prepared immediately before use. In a bottle with 1.0 g of methicillin, 1.5 ml is injected through a needle special water for injections, either 0.5% novocaine solution, or sodium chloride solution.

Adults are given an injection every four to six hours. In severe manifestations of the disease, the dosage of the drug can be increased from one to two grams.

For infants (up to 3 months), the daily dosage is 0.5 g.

For children and adolescents under 12 years old, this drug is attributed per kilogram of the child's weight - 0.025 g. Injections are made after six hours.

Children who have crossed the 12th year - 0.75-1.0 g of methicillin sodium salt in solution every six hours, or the dosage of adults.

The course of treatment is dictated by the severity of the disease.

Limit the use of this drug to persons suffering from an individual intolerance to penicillin.

• Ampicillin

This drug is not food-related. A one-time adult can take 0.5 g, while the daily dosage can be indicated by a figure of 2 - 3 g. For babies under the age of four, the daily dosage is calculated per kilogram of the baby's weight and is 100 - 150 mg (it is divided into four to six doses). The course of admission is individual, prescribed by the attending physician and lasts from one to three weeks.

This drug is quite insidious in terms of side effects: gastrointestinal tract (exacerbation of gastritis), stomatitis, dysbiosis, diarrhea, nausea with vomiting, sweating, abdominal pain and many others. This drug is contraindicated in children under the age of three; with increased sensitivity to the components of the drug, pregnant women and mothers who are breastfeeding.

Immunostimulants are also prescribed to such patients in order to push the patient's body to resist the disease.

• Immunal

The solution is prepared immediately before use by diluting the solution with a small amount of boiled water. The dosage is individual and calculated for each age. It is taken internally, three times a day.

• For babies from one to six years - 1 ml of solution.
• For adolescents from six to 12 years old - 1.5 ml.
• Adults and adolescents who have already turned 12 years old - 2.5 ml.

The medicine can also be taken in tablets:

• Babies from one to four years old. Crush one tablet, dilute with a small volume of water.
• Babies from four to six years old - one tablet from one to two times a day.
• For adolescents from six to 12 years old - one tablet, one to three doses per day.
• Adults and adolescents over 12 years old - one tablet three to four doses per day.

The course of treatment is at least one week, but not more than eight.

Immunal is contraindicated for use in the case of: children under one year old (when taking a solution) and up to four years old (when taking tablets), hypersensitivity to the components of the drug, as well as to plants of the Asteraceae family; with tuberculosis; leukemia; HIV infections and others.

• Timalin

Introduced intramuscularly. The solution is prepared immediately before injection: the volume of one vial is diluted with 1 - 2 ml of isotonic sodium chloride solution. The mixture is shaken until complete dissolution.

The drug is administered:

• to a toddler up to a year - 5 - 20 mg. Daily.
• A baby of one to three years old - 2 mg throughout the day.
• A preschooler from four to six years old - 3 mg.
• To a teenager seven - 14 years old - 5 mg.
• Adult - 5 - 20 mg daily. The general treatment course is 30 - 100 mg.

Duration of admission is from three to ten days. If necessary, the treatment can be repeated after a month.

This drug does not have any special contraindications, except for individual intolerance to its components.

If the reason for the violation of taste was a zinc deficiency in the body, then the patient, most likely, will only need to drink some zinc preparation. For example, zincteral.

• Zincteral

A tablet that should not be chewed or divided. For adults, it should be taken one hour before meals three times a day, or two hours after meals. Gradually, as taste is restored, the dosage can be reduced to one tablet per day. For children over four years old, the dosage is one tablet per day. There are practically no contraindications for this drug, except for hypersensitivity to the components that make up the drug.

If it turns out that smoking is the cause of the loss of taste perception, then you will have to rip out one thing: either smoke and not feel taste delights, or quit smoking and regain the “taste of life”.

Prophylaxis

It is quite difficult to decide on preventive measures if the cause of taste disturbance can be such a huge number of diseases that are different in genesis and severity. And yet, prevention of taste disturbances is possible.

• Leading a healthy lifestyle. For example, smoking or alcohol can be one of the causes of a taste disorder.
• Increasing the amount and variety of spices consumed. Excellent training of the receptor apparatus.

Don't forget about personal hygiene:

• Brushing your teeth in the morning and evening.
• The toothbrush and toothpaste must be selected correctly.
• Rinsing the mouth after each meal, which, if not removed, begins to rot, creating a fertile soil for the development of pathogenic bacteria.
• It is necessary to wash your hands not only before eating, but also after using the toilet, and upon coming home from the street.
• Preventive visits to the dentist. Complete sanitation of the oral cavity is a good barrier in the fight against infectious and fungal diseases.
• The diet should be harmoniously balanced. It must contain a sufficient amount of minerals and vitamins.
• If necessary, according to the doctor's prescription, it is necessary to take zinc and iron preparations.
• If the disease has arisen, it must be treated “without putting it on the back burner,” and the course must be carried out to the end, thereby eliminating all the causes of taste disturbance.

Forecast

Treatment of a taste disorder is, first of all, stopping the disease or treating it until the disease that caused this pathology is completely recovered. The prognosis of a violation of taste will also be determined by the prognosis that can be given to the disease provoking this violation.

Interesting things have been noticed, it turns out that people who are happy to consume food that has a bitter taste, consume it with the same pleasure. fatty foods... This leads to the acquisition of extra pounds, and subsequently, to atherosclerosis and other various diseases, which, in turn, can lead to a violation of taste.

Most women, in life, have a sweet tooth (this is their genetic predisposition), and this gene is double. Therefore, their gustatory palette is richer, and they can easily distinguish dozens of tones and half tones of sweet. Those with a sweet tooth are less adherent to fatty foods, so they are less likely to suffer from diseases such as heart attacks or strokes.

To one degree or another, taste disturbances are a fairly common phenomenon in our life. It may arise for a short time, due to some domestic reasons, or it may "make friends" with you for a long time. In any case, do not let the situation take its course and do not dismiss it. After all, this, it seemed, a slight deviation from the norm, may be one of the symptoms of a serious illness. And it depends only on you how quickly doctors can diagnose the disease and start treating it. Take care of yourself and be more attentive to your health - after all, this is the most valuable and precious thing you have!