The human olfactory system. Description of a complex process. Main pathways and centers of the olfactory system

Good job The sense of smell of a person makes his perception of the world around him brighter. How our sense of smell works and what influences it.

Is the sense of smell important to humans?

Our sense of smell serves us both as a means of enjoyment, allowing us to smell pleasant aromas, and as a valuable tool that warns us about possible danger. A good sense of smell plays an important role in life, makes the perception of the world around us richer and brighter, and with a bad one, life becomes gray and dull.

A person's sense of smell is not only one of the channels for obtaining information, but also a way of knowing the world. A child whose perception of smells is impaired cannot develop properly and lags behind their peers in development. The sense of smell is closely related to taste. Even a slight loss of the ability to distinguish and feel subtle smells will negate the pleasure of the most beautiful food. To some extent, we select our surroundings by smell. It is unlikely that you will be able to communicate a lot with a person whose smell is unpleasant to you.

Smells create a mood. Working, joyful, melancholic... For example, the smells of mint and cinnamon increase attention and reduce irritability, while lemon and coffee promote clear thinking. The human nose can distinguish up to 10,000 scents. This is the wealth of each of us, given by nature. And this wealth should be treasured. In order not to lose the opportunity to smell flowers or the aroma of herbs after rain, the smell of the forest or the sea. This property cannot be bought, but it can be preserved and multiplied.

The human olfactory organ. How are our perceptions of smells formed?

The sense of smell is the ability to perceive and distinguish the smells of substances in environment. The perception of smells always provokes the emergence of certain emotions. And as such, the sense of smell can often be more important than good vision or excellent hearing. The effect of aromatic substances on olfactory analyzer excites nervous system, which leads to a change in the functions various bodies and body systems.

A person's sense of smell is carried out by his olfactory analyzer, which we usually call the olfactory organ. The olfactory system begins with the perception of olfactory stimuli and consists of the following parts: olfactory mucosa, olfactory filaments, olfactory bulb, olfactory tract, cerebral cortex. The peripheral part of the olfactory analyzer, the human olfactory organ, is the receptor cells of the olfactory epithelium located in the mucous membrane of the upper posterior part of the nasal cavity, in the region of the upper nasal passage and the adjacent part of the nasal septum, as well as the olfactory nerve. The olfactory epithelium covers an area of ​​about 2 cm 2 .

Signals from the olfactory receptor cells of the olfactory organ, of which there are up to 10 million in humans, are sent along the nerve fibers to brain, where the formation of an idea of ​​the nature of the smell or its recognition takes place.

Odor receptors belong to the endings of two pairs of cranial nerves: olfactory and trigeminal. The axons of the olfactory cells form thin nerves resembling threads. These filaments pass into the cranial cavity through holes in the lamina ethmoid bone nose and join olfactory bulb, which passes into the olfactory tract. The cortical zones of the olfactory analyzer are attributed to the limbic system or the system of the visceral brain, which is involved in the regulation of innate automated activity - food, search, sexual, defensive, emotional. The functions of the visceral brain include maintaining homeostasis, regulating autonomic functions, the formation of emotions and motivational behavior, its role in the organization of memory is significant - a function closely related to emotions.

The olfactory analyzer affects the thresholds of color perception, hearing, taste, excitability vestibular apparatus. A sharp decline A person's sense of smell slows down the pace of his thinking. The structure of the olfactory analyzer has a number of features that distinguish it from other sensitive systems. The structures of the olfactory analyzer take an important part in the organization of behavioral reactions, emotions, autonomic-visceral regulation, memory processes, regulation of the activity of other areas of the cerebral cortex. Many substances that have pungent odor(for example, ammonia or vinegar essence), along with olfactory, have an effect that irritates sensory fibers trigeminal nerve, which determines the specificity of the formation of the sense of smell. Olfactory stimuli can reflexively change the frequency of breathing, blood pressure and pulse.

The human olfactory organ is highly sensitive, having low threshold arousal, different for various substances. The ability to distinguish odors is individual and different in relation to individual odors in each person. For odorous substances, the perception threshold, that is, the minimum concentration of a substance that can cause a reaction of the olfactory organ, can be very low. For example, a person smells vanillin at a concentration of 5x10-13 g/ml. At the same time, the threshold of perception of the olfactory organ undergoes fluctuations depending on the time of day (the perception of smells after sleep is brighter) and physiological state. Our sense of smell is more acute when we are hungry and also during the spring and summer months.

Human sense of smell and emotions.

Studies of brain development show that hemispheres gradually developed from the olfactory brain of primitive animals. forebrain responsible for higher nervous activity. The features of the sense of smell convincingly show that the smell is the initial source and means of transmitting information in wildlife. For animals, as well as for primitive man, the sense of smell is a way of finding food, a sexual partner, a warning of danger or marking a zone of stay.

For modern man the leading way of transmitting information was verbal, displacing or formalizing all others that had previously arisen. However, the smell remains. powerful tool impact on emotional sphere and related processes. This impact often occurs on a subconscious level. And this one life experience does not always carry positive charge, fixing and painful manifestations in the form psychosomatic diseases. Emotions speaking like early forms reactions, cover the entire body, affecting the vital activity of all its organs.

The close connection of emotions, long-term memory and sense of smell suggests that smell is a powerful means of influencing the body and human perception of the world.

The well-known scientist and researcher I.P. Pavlov believed that the problem of sensing smells and tastes is one of the most difficult in both physiology and human biology. Surprisingly, the nose is able to recognize and fully identify over 4,000 different odors.

If a person's sense organs are extremely sensitive, then this figure increases to 10,000. In addition, information about each smell is transmitted to the brain separately.

Do we always sense and understand smells correctly? Physiology of smell, investigated big amount scientists showed that the olfactory nerves healthy person in 99% of cases they transmit information about the surrounding reality. This means that the senses will never send a signal to the brain about the smell of a rose if the scent of jasmine is in the air.

But, a person is not as unique and amazing as it might seem. We are not so sensitive to our environment. If we compare the sense of smell of humans and cats, it turns out that the latter have a much better developed sense of smell. Cats are able to distinguish the smell of a person approaching them from a whole block away.

Nevertheless, the sensitivity of the human nose is simply incredible. For example, we can smell vanillin even if its concentration in the air is only 1 gram per 10 million cubic meters of air. This is an amazing number!

All objects that surround us have their own smell. As you know, odors have the ability to be absorbed. That's why our clothes are so heavily soaked huge amount aromas ranging from the trail of perfume, ending with the smell of food.

The sense organs are necessary for a person in order to protect himself from adverse factors environment. So, the smell of fire warns us of danger, the aroma of food provokes hunger, the ears can hear the noise of an approaching car, and the eyes help fix this picture in the mind.

If one of the sense organs stops working, then we instantly begin to feel defenseless and weak. Therefore, it is so important to monitor the state of hearing, vision, smell, taste and touch.

Research on the sense of smell has shown that humans only smell when they inhale. You can check it like this: bring a bottle of perfume to your nose and hold your breath for a few seconds. Oddly enough, but you can not feel the smell.

A certain category of smells is a favorite for a person. These are the aromas that a person recognizes, even if he has heard them only a few times. For example, we recognize the smell of a loved one's perfume with 100% probability if we hear it on someone else. Every mother recognizes the scent of her child.

But, each of us has those smells that cause unpleasant associations. Not happy with the sense of smell concentrated essential oils, as well as specific odors associated with unpleasant life situations. This is due to the fact that the human brain "remembers" the smell of danger, joy, sadness, grief, etc. For example, if we have encountered a fire at least once in our lives, then automatically for our body the smell of burning, fire and ashes becomes a danger signal.

But the smell of coffee can give a person cheerfulness and energy. So it is not at all necessary to drink this drink in the morning, you can just smell the coffee beans. Also, aromatic substances can excite a person, stimulate his memory, or give a signal of impending danger.

How is the sense of smell arranged?

We smell smells due to the fact that the sense organs have hypersensitivity. What does this mean? A study of the sense of smell has shown that aromas in the air provoke swelling of the mucous membranes of the nose. They begin to get irritated, the receptors are activated, and the odor molecules penetrate the nasal membrane.

The sense organs are presented in the form of mucous membranes. For example, when we smell food, then at that moment about 5,000 square meters. see the tissues of the nasal passages come into action. Human olfactory cells are physiologically represented in the form of a kind of spindle, represented by two processes - peripheral and central.

The peripheral process is located on the surface of the mucous membrane. Its peculiarity is that it is covered with thin cilia, which at the same time are an accumulation of receptor cells. Surprisingly, we perceive aromas with more than 20 million receptor cells. It is they who identify the smell around us.

Charm mechanism

The so-called olfactory club, located in the nasal sinus, is able to come into contact with the aromatic substance. If the smell is a kind of irritant of the sense organ, then the mace prevents the smell from immersing in the epithelium of the mucous membrane. The olfactory organs are directly connected to the brain through thin threads that penetrate the central parts of the olfactory cells. These threads are a link that allows a person to protect himself from danger or to enjoy the surrounding objects.

The sense organs are closely related. If a person is diagnosed with a runny nose or inflammation of the nasopharynx, then the taste of food, and even more so its smell, will not work.

How can you smell?

The sense organs are not as complicated as it seems at first glance. The smell comes from the environment, irritates the receptors, then a signal enters the brain and its feedback determines how we smell smelling substances.

The study of the human sense of smell has been going on for several centuries. About 2000 years ago, the first theory was proposed about how and why a person senses aromatic substances and which organs are responsible for this. If we turn to the theory of these studies and try to understand, then on this moment identify 4 assumptions of how we understand and hear the smelling world around us.

The classification includes the following ways odor perception:

• Contact;
• Wave;
• Physical;
• Chemical.

Based on the research of scientists, the wave theory cannot be fully extended to humans, but it can be successfully applied to mammals. For example, albatrosses are able to smell fish at an altitude of 3000 meters, and bees can smell honey even in a sealed box.

The physical theory put forward by the scientist G. M. Dison indicates that the molecules of an odorous substance are able to enter into chemical reaction with human olfactory molecules and thereby transmit a signal to the brain through nerve endings.

Chemical theory says that in nature there are only 7 primary odors, which, when combined with each other, lead to the formation of various aromatic combinations. The scientist J. Aimur put forward a hypothesis that the molecules of all these combinations have their own shape. For example, a musk molecule is presented in the form of a disk, mint - in the form of a blade, esters - in the form of a stick. Oddly enough, it was this theory that was established in human biology and anatomy.

Of all the sense organs, the most important and significant role sight and hearing play a role in human life. That's why for a long time it is these channels that connect us with the outside world have been the most actively studied. But the olfactory analyzer attracted the attention of physiologists to a much lesser extent. Indeed, the sense of smell in humans, and indeed in primates in general, is relatively poorly developed. Nevertheless, its role in our life should not be underestimated.

Even a newborn baby from the first hours of life reacts to odorous substances, and at the 7th–8th month of life, conditioned reflexes to “pleasant” and “unpleasant” odors are formed in him.

A person is able to perceive more than 10,000 smells. Some of them can excite or discourage appetite, change mood and desires, increase or decrease efficiency, and even make you buy something that is not very necessary. In many stores in Europe and America, fragrances are used with might and main to attract customers. According to the American marketing service, in itself aromatization of air in the store can increase sales by 15%. Even five fragrances are installed, which, being present in the store, are able to “provoke” the visitor to buy underwear and outerwear. These are vanilla, lemon, mint, basil and lavender. Grocery supermarkets should reign fresh smells: warm bread, cucumbers and watermelons. And then there are the smells of the holidays. For example, before the New Year, shops should smell of tangerines, cinnamon and spruce or pine needles. For most people, these smells are firmly associated with memories of the holiday and give them pleasure. However, in some people (especially children), sprayed fragrances can cause allergies. So, maybe it's good that in our stores "advertising" fragrances are not sprayed yet.

Smells can easily "stir up" our memory, bring back long-forgotten sensations, for example from childhood. The fact is that the centers of the olfactory analyzer are located in a person in the ancient and old cerebral cortex. Next to the olfactory center is the center responsible for our emotions and memory. Therefore, smells for us are emotionally colored, awakening not logical, but emotional memory.

The perception of smell by our olfactory system begins with the nose, or rather, with the olfactory epithelium, which is located in humans in upper divisions the middle turbinate, in the superior turbinate and the upper part of the nasal septum. The peripheral processes of the receptor cells of the olfactory epithelium end in an olfactory club decorated with a bundle of microvilli. It is the membrane of these villi (cilia and microvilli) that is the site of interaction between the olfactory cell and molecules of odorous substances. In humans, the number of olfactory cells reaches 6 million (3 million in each nostril). This is a lot, but in those mammals in whose life the sense of smell plays a significant role, these cells are immeasurably more. For example, a rabbit has about 100 million of them!

In the human embryo, the development of olfactory cells occurs quite quickly. Already in the 11-week-old fetus, they are well differentiated and presumably able to perform their function.

The receptor cells of the olfactory epithelium are constantly updated. The life of one cell lasts only a few months or even less. With damage to the olfactory epithelium, cell regeneration is significantly accelerated.

But how does the excitation of olfactory cells occur? IN last decade it became clear that the main role in this process belongs to receptor proteins, the molecules of which, interacting with the molecules of odorous substances, change their conformation. This leads to the launch of a whole chain of complex reactions, as a result of which the sensory signal is converted into a universal signal of nerve cells. Further, from the receptor cells along their axons, which form the olfactory nerve, the signal is transmitted to the olfactory bulbs. Here comes it primary processing, and then the signal along the olfactory nerve enters the brain, where its final analysis takes place.

The ability to smell smells changes with age. The acuity of smell reaches a maximum by the age of 20, remains at the same level for about 30–40 years, and then begins to decline. A particularly noticeable decrease in the acuity of smell is manifested in people over 70 years old, and sometimes even 60 years old. This phenomenon is called senile hyposmia, or presbyosmia, and is far from being as harmless as it might seem. Older people gradually cease to perceive the smell of food and therefore lose their appetite. After all, the aroma of food is one of necessary conditions for the production of digestive juices in the gastrointestinal tract. No wonder it is said: "... such a wonderful smell that even saliva flowed ...". In addition, gustatory and olfactory receptions are very close. The odorous substances contained in food enter the nasal cavity through the nasopharynx, and we feel their aroma. But with a runny nose, no matter what we eat, it seems that we are chewing tasteless cardboard. Similarly, food is perceived by older people with a sharply reduced sense of smell. They also lose the ability to smell the quality food products, and therefore, can be poisoned by eating poor-quality food. And yet, as it turned out, older people no longer perceive the smell of mercaptans as unpleasant. Mercaptans are substances added to natural gas used in everyday life (which in itself does not smell of anything from a human point of view) specifically in order to be able to smell its leakage. Old people stop noticing this smell...

But even in young people, the sensitivity to the smell of the same substances varies greatly. It also changes depending on factors. external environment(temperature, humidity), emotional state and hormonal background. In pregnant women, for example, against the background of a general decrease in the sharpness of the sense of smell, sensitivity to certain odors sharply increases. In general, the range of threshold concentrations of various odorous substances perceived by a person is very large - from 10-14 to 10-5 mol per 1 liter of air.

So far, we have talked mainly about external smells, originating from the world around us. But among the odorous substances there are those that are secreted by our body itself and are capable of causing certain behavioral and physiological reactions in other people. Substances with such properties are called pheromones. In the animal world, pheromones play a huge role in the regulation of behavior - we already wrote about this in our newspaper (No. 10/1996 and No. 16/1998). In humans, substances have also been found that have a certain pheromonal effect in the process of our communication. Such substances are found, for example, in human sweat. In the 70s. 20th century researcher Martha McClintock found that women who live in the same room for a long time (for example, in a hostel) synchronize their menstrual cycles. And the smell of a man's secret sweat glands causes women to normalize unstable menstrual cycles.

Tapestry "Lady with a Unicorn" - an allegorical image of smell

The smell of the secretion secreted by our axillary sweat glands depends both on the substances secreted by the body itself and on the bacteria present in the sweat glands. After all, it is known that in itself fresh axillary sweat (abundantly released, for example, in hot weather) does not have a strong specific smell. But the activity of bacteria contributes to the release of odorous molecules, initially associated with special carrier proteins from the lipocaine group.

Chemical composition male and female sweat varies greatly. In women, it is associated with phases menstrual cycle, and a man who has been in intimate relationships with a woman, is able to determine by smell the time of the onset of ovulation in his partner. True, as a rule, this happens unconsciously - it’s just that during this period the smell of a girlfriend becomes the most attractive for him.

In the secretions of the sweat glands of both men and women, in addition to other components, there are two odorous steroids - androstenone (ketone) and androstenol (alcohol). For the first time, these substances were identified as components of the sex pheromone contained in the saliva of the boar. Androstenone has a strong specific smell, for many people similar to the smell of urine. The smell of androstenol is perceived as musky or sandalwood. The content of androstenone and androstenol in the male armpit sweat much higher than for women. Studies have shown that the smell of androstenone can affect the physiological and emotional condition people, in particular to suppress the above-described effect of synchronization of sexual cycles in women living in the same room. In some situations, the faint smell of androstenone creates a comfortable state of "security" in women, while in men, on the contrary, it causes discomfort and is associated with rivalry and aggression.

Representatives of different cultures may perceive the same smells differently. Such differences were revealed in a completely unique survey conducted in 1986 by National Geographic magazine. The next issue of this magazine included samples of six odorous substances: androstenone, isoamyl acetate (smells like pear essence), galaxolide (smells like synthetic musk), eugenol, a mixture of mercaptans and rose oil. Substances were enclosed in microcapsules deposited on paper. When the paper was rubbed with a finger, the capsules were easily destroyed and the odor was released. Readers were asked to smell the proposed substances, and then answer the questionnaire. It was necessary to evaluate the intensity of the proposed smells, to determine them as pleasant, unpleasant or neutral, to talk about the emotions and memories they evoke. Respondents were also asked to indicate their age, gender, occupation, country of residence, race, presence of diseases, etc. For women, it was necessary to indicate the presence of pregnancy. Letters with completed questionnaires came from more than 1.5 million people living on different continents!

Baker of the house of Amun offering incense to Osiris

Very many of the respondents did not smell androstenone at all, and the number of people who are not sensitive to this smell varied greatly in different regions. the globe. So, if in the USA about 30% of women did not smell this smell, then among white women living in Africa, there were half as many of them - about 15%.

We have already described the loss of olfactory acuity in the elderly, which was also clearly revealed in the course of this study. The survey also confirmed that smoking people smells much worse than non-smokers.

Sent their answers to National Geographic and the people different reasons completely devoid of smell. It turns out that there are a lot of such people, including among young people. According to National Institute US health in 1969, olfactory disorders were noted in 2 million people, and by 1981 this figure had risen to 16 million! This situation is largely due to the deterioration of the environmental situation. Among patients at the Smell and Taste Clinic in Washington, 33% of patients with dysosmia (impaired sense of smell) are people aged 17–20 years. According to the researcher Hendrix in 1988, 1% of the population of the Netherlands had problems with smell. As for our country, very often people, crushed by other problems, simply do not pay attention to such a “trifle” as a violation or lack of smell. And if they do, they don’t know if it is possible in this case health care and where to go for it. Treatment of people with impaired sense of smell is carried out in Moscow, in the ENT clinic of Moscow medical academy them. THEM. Sechenov.

What can cause a violation of the sense of smell? Most often, the corresponding disorders are associated with damage to the receptor apparatus of the olfactory analyzer (about 90% of cases), with damage to the olfactory nerve - about 5% of cases, and with damage to the central parts of the brain - the remaining 5% of cases.

The reasons for the olfactory disturbance of the "receptor level" are very diverse and numerous. These are injuries of the olfactory zone and sieve plate, and inflammatory processes in the nasal cavity, and craniocerebral trauma, and drug intoxication, and allergic reactions, and mutations, and beriberi (for vitamins A and B12), and intoxication with salts heavy metals(cadmium, mercury, lead), and inhalation of vapors of irritating substances (formaldehyde), and viral lesions (mainly influenza virus), and ionizing radiation, and much more.

The causes of damage to the olfactory nerve are most often due to infectious diseases, disorders metabolism, toxic effects of drugs, nerve damage during surgical operations and tumors.

Damage to the centers of the olfactory analyzer can be caused by traumatic brain injury, impaired cerebral circulation, brain tumors, genetic and infectious diseases, demyelinating processes, Parkinson's disease, Alzheimer's disease. In the last two diseases, a decrease in the acuity of smell is often detected even in the early stages, which allows you to start treatment earlier.

What is the violation of the sense of smell? It could be complete absence the ability to perceive odors (anosmia) or a decrease in the sharpness of smell (hyposmia) of varying severity. Olfactory impairment can also be expressed as a distortion of odor perception (aliosmia), in which all odors are perceived "in the same manner." For example, in what cosmos all odors seem putrid and fecal; with torcosmia - chemical, bitter, smells of burning or metal; with parosmia, "garlic smells like violets." Mixed cases are also possible, and phantosmia - olfactory hallucinations.

Many of the smell disorders described are successfully treated - especially if you do not delay visiting a doctor.

The sense organs are very important for all of us. The human sense of smell can make the perception of the world much brighter.

The role of the olfactory organ

The organ of smell is the nose, which serves us so that we can enjoy wonderful smells, aromas. He also warns us about various kinds hazards (fire, gas leakage). A good sense of smell is very important for any person, because without it it is impossible to perceive the world at 100%. So, with a poor sense of smell, life can become gray and dull, devoid of all colors.

The olfactory organ is a tool for obtaining information, it helps a person to understand the world. It is known that children whose perception of smells is impaired cannot develop properly and lag behind their peers. The organ of smell is closely related to the organ of taste. A very small loss of the ability to subtly feel and distinguish smells nullifies the pleasure of the tasty food. And people often choose their environment by smell. Probably, no one will be able to communicate with a person for a long time if his aroma is not very pleasant.

The olfactory organ, helping us to perceive smells, is able to create mood and influence well-being. For example, the scents of cinnamon and mint can increase alertness and reduce irritability, while the scents of coffee and lemon help clear thinking. The human olfactory organ has the ability to distinguish up to 10,000 aromas. This wealth, given to us by nature, must be cherished. No one wants to stop smelling flowers, herbs, forests, seas.

What is smell?

The ability to distinguish and perceive various odors of substances that are in the environment is the sense of smell. The recognition of odors usually provokes the emergence of various emotions. In this sense, the sense of smell often becomes more important than, for example, good hearing or excellent vision. The impact of various aromatic substances on the organ of smell can excite the human nervous system. This, in turn, leads to a change in the functions various organs and systems throughout the body.

Organ device

The olfactory organ is the nose, which perceives the corresponding stimuli dissolved in the air. The olfactory process consists of:

• olfactory mucous membrane;
• olfactory thread;
• olfactory bulb;
• olfactory tract;
• cerebral cortex.

The olfactory nerve and receptor cells are responsible for the perception of smells. They are located on the olfactory epithelium, which is located on the mucous membrane of the upper posterior part of the nasal cavity, in the region of the nasal septum and upper nasal passage. In humans, the olfactory epithelium covers an area of ​​about 4 cm 2 in size.

All signals from the receptor cells of the nose (of which there are up to 10 million) through nerve fibers enter the brain. There, an idea of ​​the nature of the smell is formed or its recognition occurs.

In humans, there are olfactory and trigeminal nerves, to the ends of which odor receptors are attached. Nerve cells have two types of processes. Short, called dendrites, are shaped like sticks, each of which contains 10-15 olfactory cilia. Other, central processes (axons) are much thinner, they form thin nerves that resemble threads. These very threads penetrate the cranial cavity, using holes in the plate of the ethmoid bone of the nose, and then join the olfactory bulb, which passes into the olfactory tract. The bulb lies at the base of the skull and makes up a special lobe of the brain.

The visceral brain system, or limbic system, includes the cortical zones of the olfactory analyzer. These same systems are responsible for the regulation of innate activity - search, food, defensive, sexual, emotional. The visceral brain is also related to the maintenance of homeostasis, the regulation of autonomic functions, the formation of motivational behavior and emotions, and the organization of memory.

Peculiarity

The olfactory organ is able to influence the thresholds of color perception, taste, hearing, excitability of the vestibular apparatus. It is known that if a person's sense of smell is sharply reduced, then the pace of his thinking slows down. The structure of the olfactory organ is special, it distinguishes it from other sense organs. All structures of the olfactory analyzer take an important part in the organization of emotions, behavioral reactions, memory processes, vegetative-visceral regulation, regulation of the activity of other areas of the cerebral cortex.

There are substances that have a pungent odor (ammonia, vinegar essence). They are able to have both an olfactory effect and an irritant effect on the sensory fibers of the trigeminal nerve. This explains the specificity of the formation of odor sensations. Reflex can change the frequency of breathing, pulse, blood pressure under the influence of olfactory stimuli.

Organ sensitivity

The sharpness of the sense of smell can be judged by the fact that a person is able to clearly perceive, for example, the smell of 0.0000000005 fractions of a gram of rose or musk oil, about 4.35 fractions of a gram of mercaptan gas. If the air contains even 0.00000002 g per 1 cm 3 of hydrogen sulfide gas, then it is clearly noticeable by us.

There are smells that have great strength and durability and can even be stored for 6-7 thousand years. An example of this is the smells that people who participated in the excavations felt. Egyptian pyramids. It can be said that our nose is able to detect various impurities of odorous substances in the inhaled air in very small quantities that cannot be measured even with the help of chemical studies. It has been proven that the sharpness of the sense of smell depends on the time of day (after sleep, smells are better felt) and the physiological state of a person. The sense of smell is more acute when a person is hungry and also during spring and summer.

The human olfactory organ is capable of distinguishing no more than a few thousand different shades of odors. In this we are very far behind the animals. Dogs, for example, can recognize about 500,000 scents.

Smell and emotions

Studies of the brain indicate that the hemispheres of the forebrain, which are responsible for higher nervous activity, gradually formed from the olfactory brain in the process of evolution. Smell is the primary source and means of conveying various information among creatures in wildlife. In addition, for all animals and for primitive man, the olfactory organ is necessary for finding food, a sexual partner, warning of danger, or marking a habitat.

For a person living in modern world, the main way of transmitting information becomes verbal, which was able to displace all others that had arisen earlier. It is known that the smell has a powerful effect on the emotional sphere, as well as the processes associated with it. This effect often occurs at the subconscious level. This experience in a person's life is not always positive. For example, manifestations of diseases in the form of psychosomatic diseases are recorded.

The importance of smell

The functions of the olfactory organ are numerous in the life of all living beings, as it is able to warn of the danger of poisoning by poisonous gases that can enter the body through the lungs. It is also possible to control the quality of the food consumed with the help of smell, which protects against the entry of decomposed and poor-quality products into the gastrointestinal tract.

Conclusion

As a conclusion, it can be said that close connection long-term memory, emotions and sense of smell suggests that smell is a powerful means of influencing the entire human body and its perception of the world as a whole.

The role of smell in the life of a modern person cannot be underestimated. Surprisingly, the sense of smell gives us the ability to smell more than 10,000 different smells. Most smelling substances can increase a person's appetite or stimulate good mood, and also contribute to the activation of brain activity.

The nose is so sensitive that some marketers use it in business. For example, how many times have you made a successful or not very successful purchase under the influence of an enchanting aroma in a store?

The sense of smell allows a person to avoid the dangers that reign around, and also stimulate the pleasure of objects and people who are nearby. But, for some reason, we underestimate the role of smell in our lives. In most cases, a person's nose is an organ whose existence is remembered only when it is affected by various infectious or inflammatory processes.

The sense of smell is extremely highly developed in a person from his very birth. For example, a newborn may not see or hear his mother, but by smell he is able to recognize her from hundreds and even thousands of other women. Unfortunately, main body smell - the nose, begins to lose its sensitivity already in the second year of a small person's life.

With the passage of each year of life, the sense of smell decreases, and sensitive receptors atrophy one by one. This is an irreversible process that no one can help to influence. So, upon reaching old age, a person may notice that he no longer hears the smells around him so clearly. And this is absolutely normal, which can only be corrected by strong drug therapy.

A person's sense of smell can decrease not only as a result of age-related changes. The nose may become less sensitive as a result of:

• Inflammatory processes occurring in the nasopharynx;
• Formation of nasal polyps;
• allergic reaction;
• Side effects after taking drugs that eliminate cardiovascular insufficiency;
• Failure to comply with oral hygiene;
• The impact of toxic substances on the body;
• Consequences of acute viral hepatitis;
• Deficiency of vitamins and minerals;
• Bad habits.

The olfactory organ loses its functionality as a result of cirrhosis of the liver, damage to the body by multiple sclerosis, the formation of benign or malignant tumors.

The sensitivity of odor receptors is reduced in people with diagnoses: Alzheimer's disease, pathological condition Parkinson's disease, epilepsy, as well as those who have suffered traumatic brain injuries or suffer from dysfunction thyroid gland. Only a specialist can determine and understand which of the above reasons affected the olfactory organ.

The ability to hear smells and personal relationships

The human sense of smell is that means of perception and obtaining information that works 24 hours a day. Few people know that the sense of smell is very closely related to the sense of taste of food. Loss of smell for most famous chefs can be equated with death.

Surprisingly, a person uses the nose not only to breathe, but also as a kind of X-ray of the surrounding people. Many people think that love for friends and a life partner is born in the heart, but this is not so.

The first instinct that works in a person is to scan the smell of an approaching person. And, if we like the odorous substances that the human body emits, then this is already the first step towards rapprochement. This is very easy to check for yourself. Is there a person in your environment whose smell you do not like?

How perceptions of smell are formed

Smell and smell are two components that work so that a person can live a full and vibrant life. The olfactory system consists of the following components:

• Olfactory stimuli;
• Olfactory threads;
• mucous membrane;
• Bulb;
• Olfactory tract;
• Cortex.

The sense of smell enters the brain through the olfactory analyzer, that is, the nose. It contains the olfactory epithelium receptor and the olfactory nerve.

The ability to perceive and analyze surrounding odors is carried out through receptor cells, of which there are about 10 million in humans. How can a person distinguish between odorous substances that surround him? The aroma enters the nose, affecting sensitive receptors, and they, in turn, transmit the corresponding signal to the cerebral cortex.

Perception of smells around us

The role of smell is manifested not only in the perception of surrounding odors, but also affects color perception, excitability of the vestibular apparatus, hearing and taste. If the nose does not function as a result inflammatory processes, then a person’s thinking slows down sharply. The sense of smell takes an active part in the formation of behavioral reactions, emotionality and memory. All substances that enter the body through the nose find a response in the form of its reaction.

So, ammonia, which has a pungent and pungent odor, provokes irritation of the trigeminal nerve, activates brain activity and bring the person back to consciousness. Thanks to the action of odorous substances, one can successfully manage the emotions and feelings of a person, which is what successful companies use in their practice. The next time you're shopping for fast food, think about it: are you really hungry or just can't resist the smell of the food?

Despite the fact that a person's sense of smell contributes to the perception of the surrounding world and the assessment of the environment, the sensitivity threshold for each person is different. So, someone's nose can react to the smell of vanillin, which comes from a neighboring street, and someone will not hear it even at a distance of a couple of centimeters.

It is interesting to know that the threshold for odor perception can rise or fall depending on the time of day and season. As a rule, the nose becomes more sensitive after long sleep, as well as during the period of exacerbation of hunger.

Even if a person good sense of smell, then he is still not able to feel and fully feel his own smell. Physiology is so arranged that we are able to perceive the smells of the people around us, but the odorous substances of our body are blocked when they enter the sensitive receptors of the epithelium.

Therefore, it is so important to pay attention to your own hygiene and monitor the amount of sweating. Surprisingly, we can get used to our own bad smell, as a result of which our sense of smell is drastically reduced. TO elementary rules and hygiene tips include daily shower, preference for clothing made from natural materials, as well as the use of deodorizing drugs.

If a person smells bad, then gradually this smell begins to spread to the room in which he lives. So creation pleasant aroma in your own home is the prevention of reduced sense of smell.

Development of the sense of smell

Experts advise to constantly develop your sensitive receptors. To do this, you need to try to surround yourself with pleasant smells. Smell training can be done by visiting perfume shops, bakeries and specialized departments that sell herbs and spices. The house where you live can be decorated with various dried herb pads that exude a pleasant aroma.

If you have a reduced olfactory function, then increase perception palatability dishes can be by adding aromatic herbs and seasonings to them. It is known that sensitivity to smells is directly proportional to appetite.

If a person does not feel the aroma of food, then his appetite does not wake up. To stimulate the taste and smell receptors, you can put a saucer with coffee beans in the kitchen. Such aromatherapy will help improve mood, eliminate depression and stimulate nasal receptors.