Where is the human sense of smell located? Description of a complex process

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. It also warns us of various kinds of dangers (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 with impaired perception of smells 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 receptor cells nose (of which there are up to 10 million) through nerve fibers come to 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 cortical zones olfactory analyzer. These same systems are responsible for the regulation of innate activity - search, food, defensive, sexual, emotional. The visceral brain is also involved in maintaining homeostasis, regulating autonomic functions, the formation of motivational behavior and emotions, the organization of memory.

Peculiarity

The olfactory organ is able to influence the thresholds of color perception, taste, hearing, excitability 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 pungent odor(ammonia, vinegar essence). They are able to have both an olfactory effect and an irritant effect on sensitive fibers. 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 scents that 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 physiological state person. The sense of smell is more acute when a person is hungry and also during spring and summer.

The human olfactory organ can distinguish no more than a few thousand various shades 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 hemispheres gradually formed from the olfactory brain in the process of evolution. forebrain who are responsible for the highest nervous activity. 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 the modern world, the main way of transmitting information is verbal, which could 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

In conclusion, we can say that the close relationship between long-term memory, emotions and smell suggests that smell is powerful tool impact on the entire human body and its perception of the world as a whole.

Answer: The organ of smell is located in the nasal cavity at the beginning of the respiratory tract. It occupies an area equal to the area of ​​a small coin in the upper nasal sinus and nasal septum.

The structure of the olfactory analyzer?

Answer: as you know, in the upper part of the nasal cavity, the so-called olfactory fissure, there is an olfactory region. The space limiting this area is the septum, the upper and middle shells, and the cribriform plate. The mucous membrane covering this area differs from the rest of the mucous membrane of the nasal cavity by brown spots, which get their color from the pigment contained in the olfactory cells: the indicated spots or islets in general occupy 250 mm2 of area and are irregular in shape. There is no exact definition of the distribution area of ​​the olfactory part of the nasal mucosa containing the pigment; this area is different in individual individuals, occupying either part of the superior turbinate and nasal septum, or passing to the middle turbinate. The olfactory pigment is similar, apparently, to the pigment of the retina, and its disappearance leads to a loss of smell, which is observed in the elderly, in people with a disease of the epithelium of the olfactory fissure.

Where is the cortical olfactory center located?

Answer: The central section is a cortical olfactory center located on bottom surface temporal and frontal cortex hemispheres. The olfactory cortex is located at the base of the brain, in the region of the parahippocampal gyrus.

organ of taste

What is the organ of taste?

Answer: Taste receptors are composed of neuroepithelial cells, contain branches of the taste nerve and are called taste buds.

Taste buds (gemma gustatoria) are oval in shape and are located mainly in leaf-shaped, mushroom-shaped and grooved papillae of the mucous membrane of the tongue (see the Digestive system section). In small quantities they are present in the mucous membrane of the anterior surface. soft palate, epiglottis and rear wall throats.

Irritations perceived by the bulbs go to the nuclei brain stem, and then to the region of the cortical end of the taste analyzer.

Receptors are able to distinguish four basic tastes: sweet is perceived by receptors located at the tip of the tongue, bitter by receptors located at the root of the tongue, salty and sour by receptors at the edges of the tongue.

Where is the organ of taste located?

Answer: The organ of taste (organum custus) is a peripheral part of the taste analyzer and is located in the oral cavity.

The structure of the taste analyzer?

Where is the cortical taste center located?

General body cover

What is the importance of the skin for the human body?

Human skin has a complex structure and performs a number of important functions. It covers the entire surface of the body and reliably protects it from negative impact external factors. Due to the peculiarities of the structure of the epidermis, it prevents the penetration of pathogenic bacteria, harmful chemical compounds, water and various contaminants into the body. In addition, the skin protects the internal organs from mechanical injuries, temperature and other physical influences. The special skin pigment melanin neutralizes the harmful effects of ultraviolet rays.

What are the layers and appendages of the skin indicated in the figure by numbers?

stratum corneum

What formations perceive pain, where are these formations located?

Answer: Pain is sensed by nociceptors.

What formations perceive touch, where are these formations located?

Answer: The organ of touch perceives tactile stimuli resulting from the touch or pressure of objects on the skin. Afferent innervation of the skin is carried out by nerve fibers coming from sensory neurons of the spinal ganglia. The dendrites of sensory neurons form tactile receptors that are found in the skin.

What formations perceive pressure, where are these formations located?

Answer: When the organs of touch and pressure are acted upon in the mechanoreceptors of the skin, the energy of the stimulus is transformed into nervous excitation, which is transmitted along a chain of neurons from the peripheral part of the skin analyzer to its cortical part - to the posterior central gyrus. In the upper part of it, the sensitivity of the skin of the legs is projected, in the middle part - of the arms and torso, and in the lower part - of the scalp.

What formations perceive the feeling of warmth, where are these formations located?

What formations perceive the feeling of cold, where are these formations located?

13 May 2009

The sense of smell gives us the opportunity to enjoy pleasant smells, and sometimes it can save our lives: not to let us drink vinegar instead of vodka, to suggest that we should not eat a rotten pie, or to remind us that we should not flip the switch when we smell gas. However, the smells around us have properties that many may not even be aware of.

Something like a human sense of smell exists even in microorganisms: chemotaxis - the ability to move towards food sources and away from hazardous substances- all mobile unicellular show. But let's skip the roughly 3.5 billion years of evolution of the sense of smell and jump right into mammals and humans.

For many animals, the sense of smell is at least as important source information than sight and hearing: any dog ​​owner knows that dogs get lost when meeting with a drunken owner: he looks and talks the same, but smells completely different! And not from the “exhaust” (the smell of paint, herring, etc. does not have such an effect), but because, together with the rest of the biochemistry, alcohol changes the composition of sweat and, accordingly, is imperceptible to human nose shades of individual smell.

For us, the ability to feel and distinguish smells, at first glance, is not so important. Sometimes it even gets in the way: everyone can recall situations when he was ready to give half his kingdom for not smelling a homeless person who got into a trolleybus or a colleague who had eaten garlic. And although without the pleasure of the smell of flowers, perfumes, food and many other aromas, the world would lose a lot, for a person, smell is in fourth place in a series of five senses. Due to vision, we receive at least 90% of information about the world around us, and without it, a person uses tactile sensations and hearing to orient in space and recognize living and inanimate objects.

Scientists have deciphered the main mechanisms of the sense of smell quite recently. This lag is due not only to the underestimation of the importance of its role in human life, but also to the extreme complexity of the arrangement of olfactory receptors.

What do we like?

Gordon Shepherd, professor of neurology at Yale University, author of the three-volume Neurobiology, which has gone through several reprints, and an incomparable expert on the mechanisms of transmission of impulses by synapses of dendritic spines of the olfactory bulb (he has such a narrow specialization), began the answer to this question like this: “We think that we smell with the help of the nose, but this is the same as saying that we hear with the lobes of the ears.” The nose itself is necessary in order to direct the air containing aromatic molecules to the olfactory epithelium - symmetrical sections of the mucous membrane located deep in the nasal cavity, slightly below eye level.

We smell odors only during inhalation, since the exhaled air passes only through the lower turbinates and does not come into contact with the respiratory epithelium. With a calm breath, only 7-10% of the inhaled air passes near the olfactory epithelium located in the uppermost part of the nasal cavity, therefore, to enhance sensations, it is necessary to inhale as deeply as possible. You can also follow the example of animals and “sniff”, taking frequent short breaths in the immediate vicinity of the object under study, which allows you to maximize the concentration of odorous molecules near the olfactory receptors.

Due to the folds, shaped like ridges, the total area of ​​the olfactory epithelium in humans is 5-10 cm2. At this second frontier of the olfactory system, according to various sources, there are from 10 to 50 million cells that register odors. In animals, their number is usually much larger. For example, the olfactory epithelium of sheep dogs contains up to 220 million receptor cells.

The olfactory receptor is a sensory (sensitive) nerve cell, from which two processes depart. To the nasal cavity - a short dendrite (a sensitive process of a neuron), which has at least 10 cilia, the tips of which are located on the very surface of the olfactory epithelium and protrude into the mucus covering it. To the brain - a longer motor (transmitting) process, an axon intertwined with the axons of other olfactory neurons in a thread olfactory nerve passing through the holes of the ethmoid bone of the skull into the olfactory bulb - a brain structure that performs the primary processing of information about odors. The olfactory bulb is the larger, the more acute the sense of smell of the animal, therefore, in sniffer dogs it is much larger than in the much larger human brain.

From the olfactory bulb nerve impulses They enter the primary, and then the higher olfactory areas of the cerebral cortex, forming a conscious sense of the nature and intensity of the smell. The end point of odor data processing is the limbic system, which regulates the body's emotional and behavioral responses.

How it works?

Molecules of aromatic substances that enter the nasal cavity with air flow dissolve in the mucus covering the olfactory epithelium and interact with receptor proteins contained in the membrane of the cilia of olfactory neurons. This interaction changes the ion permeability of the cell membrane and forms an electrical impulse that is transmitted along the axon of the cell to the olfactory nerve and further, up to motor neurons spinal cord, giving the muscles commands to pinch their nose with their fingers and move away - or vice versa.

WITH central mechanisms The olfactory system was understood by specialists who studied it quite a long time ago, but protein receptors, undoubtedly present on the membranes of olfactory epithelial neuron dendrites, remained elusive for many years. It was only in 1991 that Columbia University scientists Linda Buck and Richard Axel managed to solve this riddle. In 2004, the discovery brought them Nobel Prize in physiology and medicine.

The traditional approach to studying the mechanisms of olfactory receptors was to measure the activity of certain neurons in response to various stimuli. To do this, electrodes were connected to the olfactory nerves of the animals and allowed to inhale. various substances. As a result, it was only possible to find out that the same neuron can respond to different substances, however, the mechanisms underlying this process are for a long time remained incomprehensible.

Buck and Excel chose fundamentally new approach– they turned to the rapidly developing genetics and began the search for genes whose activity is recorded exclusively in the olfactory epithelium. Initially, their experiments were also unsuccessful, which Axel later explained by the existence of a huge number of receptor proteins, the reaction of each of which to a specific smell is too weak to be detected by existing methods.

To cope with this problem, the scientists were helped by the scheme invented by Buck, which, using three assumptions, significantly reduced the search area. According to the first assumption, based on the disparate scientific facts, it was only necessary to look for genes for proteins that have a certain similarity with rhodopsin, a receptor protein, due to which an electrical impulse is formed in the rods of the retina, cells that do not distinguish colors, but react to changes in illumination and provide twilight vision. In addition, the desired proteins should have belonged to the same family, and the genes encoding them should have been active exclusively in the cells of the olfactory epithelium.

In rats, there were about a thousand genes that met all three criteria - about 1% of the entire genome. Every 100th rat gene is involved in smell recognition, which indicates the extreme importance of the olfactory system for rodents - close relatives of primates: our branches on the tree of evolution diverged about 25 million years ago. A search in DNA libraries made it possible to find in the genomes of other species (mice, salamanders, catfish, dogs, humans and other animals) analogue genes associated with the primary perception of smells. True, unlike most animals, in which most of these genes regularly synthesize the corresponding proteins, in different types In great apes, 28-36% of the olfactory receptor protein genes are inactive, and in humans, almost 60%. Apparently, mutations that block the activity of olfactory receptor genes have been accumulating since the acute sense of smell lost its importance for the survival of human simian ancestors.

Further study of the olfactory organ system showed that each individual receptor neuron can recognize many odorous molecules, each of which activates different protein receptors on the surface of its membrane. Such a combinatorial signal coding system makes it possible to recognize an almost unlimited number of flavors.

Even molecules that differ slightly in chemical structure activate various combinations of receptor proteins located on the membranes of different neurons, so the smell of octane alcohol resembles the smell of citrus fruits, and octanoic acid, which differs from it only by one additional oxygen atom, resembles the smell of sweat.

A change in the spatial structure of molecules can lead to the same effect. For example, the smells of cumin and spearmint (it differs from the more well-known peppermint in the absence of a cooling sensation and less pungent smell) provide d-carvone and l-carvone - chiral (from the ancient Greek χειρ - "hand") isomers, molecules with the same chemical composition, differing from each other, as an object from its mirror image.

In addition, more molecules activate more wide range receptors, due to which the same substance can smell differently depending on the concentration.

The most surprising example is skatol, a heterocyclic compound formed during the decomposition of protein compounds and giving a specific odor to stool. At the same time, in small concentrations, skatole has a pleasant smell and is included in perfumery products and food essences.

The most versatile in this respect are aldehydes. For example, coconut aldehyde small concentration it smells not of coconut, but of apricot or peach, and the smell of anisaldehyde when diluted is felt like the aroma of fresh hay, rose hips and hawthorn flowers.

The most unpleasant-smelling compounds are sulfur-containing substances, starting with the simplest - hydrogen sulfide H 2 S. Mercaptans are considered “champions” among them. Their mixture provides a stink of skunk squirt that can make a person faint. Mercaptans give a unique flavor to rotten cabbage and domestic gas: Natural gas is odorless and has a tiny bit of isoamyl mercaptan added for safety reasons. Sulfur-containing compounds diallyl disulfide (CH 2 =CH–CH 2) 2 S 2 and allicin CH 2 =CH–CH 2 –SO–S–CH 2 –CH=CH 2 provide a sharp smell of garlic, and the main component of the onion smell is allyl propyl disulfide CH 2 =CH–CH 2 –S–S–CH 2 –CH–CH 3 . There are no allyls in garlic and onions themselves (belonging to the genus Allium): when cut, under the action of enzymes, numerous cysteine ​​amino acid molecules containing sulfhydryl groups –SH are converted into them. A feature of these disulfides is that it is almost impossible to get rid of the smell either by brushing your teeth or rinsing your mouth. The fact is that these compounds, having penetrated through the walls of the intestine into the blood, are carried throughout the body, including the lungs, from where they are excreted with exhaled air.

Smell in our life

The sense of smell is most important in the first minutes of a person's life, because only thanks to him the baby recognizes his mother and finds breasts smelling of milk. In the next couple of months, until the child's vision becomes sharp enough, he perceives the world around him mainly through smells. As we grow older and develop other senses, the sense of smell loses its significance. At the same time, atrophy (death) of the olfactory nerve fibers occurs. During the first year of life, the acuity of a person's sense of smell decreases by 40-50%, and the further rate and degree of deterioration in the ability to recognize odors depends on individual features body, gender, lifestyle and exposure to various factors environment. For example, in novice smokers, the ability to distinguish odors is reduced by 50-60%, after which it is restored by 20-30%. When quitting smoking, hyperosmia develops - the sharpness of smell increases by about 20% compared to the initial one.

It is believed that a person is more sensitive to unpleasant odors. Almost always, we perceive odors that signal danger as unpleasant: do not eat rotten meat or rotten fruits, stay away from hydrogen sulfide, chlorine, ammonia, do not plunge into excrement - they can contain worm eggs, dysentery amoebas and other cholera ... Those from our ancestors (still covered with scales, not wool), in which such associations did not arise, natural selection weeded out. Although there are exceptions - for example, garlic, which completely falls under the popular proverb "does not smell of its own" :)

However, substances that we can smell in the smallest concentrations smell pleasant. Vanillin has long been considered a record holder: it can be smelled at a concentration of 2 × 10 -11 g per liter of air. But more recently, it turned out that one of the chiral isomers of a substance called wine lactone (it gives the wines a sweet-coconut aroma) is felt at a concentration two thousand times lower: one hundred trillion (10-14) grams in 1 liter of air. And the smell of its mirror isomer (in the figure - on the right) can be felt only at a concentration that is 11 orders of magnitude greater - 1 mg / l.

Women in general have a sharper sense of smell, which persists into advanced age. However, paradoxically, the professions associated with the distinction of smells are exclusively male. The point is that changes hormonal background during monthly cycles female body, affect the work various bodies and systems, including the olfactory system. As a result, at the beginning of the cycle, women often develop temporary hyposmia - a decrease in sensitivity to odors. This is not observed when taking hormonal contraceptives that maintain a constant hormonal background in the body, however, it is obvious that taking pills cannot be prerequisite recruitment.

Without the sense of smell, our food would be practically tasteless. Human taste buds distinguish only four sensations: sweet, salty, sour and bitter, and combinations of aromatic substances provide the rest of the variety of tastes of various dishes and drinks. At severe runny nose when the upper turbinates are "clogged" and the air containing aromas simply does not reach them, everything seems tasteless and unappetizing. Experiments have shown that if a person with a pinched nose is also blindfolded to deprive him of visual associations with the foods he eats, he is unlikely to be able to distinguish an apple from a potato or red wine from coffee.

Smells can change the way you work various systems organism. The most obvious example is the increased production of saliva and digestive juices from food odors. sharp and unpleasant odors(for example, ammonia) increase blood pressure and speed up the heartbeat, while pleasant ones, on the contrary, lower blood pressure, slow down the pulse and cause an increase in skin temperature, which relaxes and calms the person.

How justified are the claims of aromatherapists - for example, this: “the aromas of lavender, chamomile, lemon and sandalwood weaken brain activity faster than any depressant, and jasmine, rose, mint and cloves excite cells gray matter more powerful than strong coffee? Judging by the fact that in the articles of different authors one can find directly opposite statements about the effect of odors on the psychophysiological state of a person, this effect is explained not by the nature of the smell itself, but by the psychological setting for the expected effect.

Another, perhaps the most puzzling question in the science of smells, is their role in the sexual behavior of Homo sapiens. We'll talk about this.

Evgenia Ryabtseva,
portal "Eternal youth"

Imagine for a couple of minutes that you do not smell. Life becomes completely uninteresting, flowers do not please, because they appearance without fragrance does not give the expected effect. The kitchen - and that without aromas becomes some kind of stranger. What is responsible for smell? which enables a person to feel life with all its delights.

The structure of the nose

A person smells through the nose. Before talking about the sense of smell, you should understand what this organ is. After all, its cavity performs very important function- it cleans the air from dust and unnecessary particles. It is possible to understand how this whole process takes place only when the person is known. Its anatomy is as follows:

• At the entrance are small hairs. It is they who are a kind of barrier that prevents the ingress of foreign particles and dust.
• The goblet glands are also peculiar protectors human body because they secrete mucus. It, in turn, is characterized by antiseptic properties, due to which the destruction of pathogenic bacteria occurs. In addition, mucus prevents dry and cold air from entering the human body.
• - these are four walls: lower, upper, medial, lateral.
• An area with a large number of blood vessels.
• Osteocartilaginous septum. It divides the nasal cavity into two equal parts. Its curvature can lead to difficulty in breathing.

We examined the structure of the human nose. The anatomy of this organ has its own characteristics. A lot depends on the correctness of its structure.

Summarizing all of the above, we conclude that the nose consists of two parts: the outer section and the nasal cavity. This body performs the following functions:

• protective;
• resonant;
• olfactory and others.

A little about smell

Smell is a special sense that allows you to respond to aromas. Odorants act on upper part nasal mucosa, where the olfactory nerve is located. Simply put, the sense of smell can be called the ability to smell. Each person perceives them differently, which is why experts distinguish three groups of people:

• Macromatics - have a subtle sense of smell, sensitive to aromas. They can distinguish all existing shades of smells.
• Microsmatics - they will take a little time to determine the saturation of the aroma. Statistically, there are a lot of such people.
• Anosmatics are people who do not smell at all. Their number is small.

Description of a complex process

Recognizing smells is not an easy task. And the opinion that we perceive aromas with the help of the nose is deceptive. This organ only helps us to inhale. After that, the air enters the olfactory epithelium. It contains neurosensory cells. They react very actively to the presence of smell and send an impulse to different parts of the brain: to the olfactory cortex, hypothalamus, hippocampus. Only after that a person begins to realize the smell, remember it and identify it. In addition, the hypothalamus can store associative memory. It is thanks to her that smells often give rise to certain memories.

The sense of smell is the ability to memorize a large number of odors and classify them. Why is this happening? Scientists have expressed the following opinion. Olfactory neurons contain a large number (about a thousand) of receptor proteins. Each receptor has only one protein and is responsible for a specific smell. There are ten million olfactory neurons in humans, and each of them has big amount receptors. So thanks we can recognize great amount odors, but separately.

The sense of smell is gone

Sometimes it happens that a person's sense of smell disappears or worsens. Why is this happening? Most often this is due to damage to the nasal mucosa or intracranial processes. Agree that the loss of smell, as well as the loss of taste, is not a very pleasant situation for a person. What is causing such a problem?

• Swelling of the mucous membrane of the nasal septum. This is due to the presence of diseases such as SARS, rhinitis, sinusitis, as well as with a curvature of the septum, allergies, and the presence of nasal polyps.
• Violation of the secretion of the mucous membrane. At the same time, the cilia, thanks to which odors are captured, are immersed in a secret.
• Disruption of the olfactory neuroepithelium. It happens when you inhale toxic substances, acute infections.
• Traumatic brain injury.
• Tumors.
• Taking neurotoxic drugs.
• Some congenital diseases.
• Neurosurgical intervention.
• Receptor dysfunction.
• Underdevelopment of the olfactory pathways.
• Smoking.
• Age changes.

Bringing back the sense of smell

If the ability to recognize odors is lost, it should be returned. According to statistics, most often the lack of smell occurs due to colds, the presence of polyps. In a word, when a mechanical obstacle appeared, which does not allow you to enjoy the aromas. Based on the cause, a decision should be made on how to restore the sense of smell.

For diseases of the mucous membrane, doctors act as follows:

• Eliminate all factors that caused the loss of smell.
• Medications are prescribed on an individual basis.
• Assign physiotherapy.
• If necessary, surgical treatment is used.

Therapy and Nutrition

Not always when a problem occurs, a person seeks to go to the doctor, in most cases he tries to find the answer himself to the question of how to restore the sense of smell. Most often, home treatment is successful if you have simple rhinitis.

With a cold, mucous fluid accumulates gradually. But the appearance of mucus is also influenced by nutrition. If your diet is high in starchy foods or processed foods heat treatment, the sense of smell may leave you. If this happens, then the first thing to take care of is a change in diet. At the time of treatment, you can even switch to vegetarian food or simply refuse fatty meat. In addition, you will have to limit the consumption of milk and potatoes, as well as exclude confectionery and bakery products, all fatty and smoked sugar from the diet.

Therapeutic baths

In order to restore the sense of smell, it is necessary to adhere to certain sequence during treatment:

• Soften the mucus. To do this, it is recommended to make a steam bath. It will also help clear the lungs and bronchi. Three procedures for 15-20 minutes will be enough. Remember that if you have dry facial skin, apply a cream to it before the procedure.
• For greater steam efficiency, add young dill, sage, mint or nettle to the water.
• Bend over the bath, cover your head with a towel. Inhale through your nose, exhale through your mouth.
• After the bath, take a shower, but do not wet your head.
• Stretch your body. To do this, you can wave your arms, legs, tilt and rotate your head, torso.

Folk remedy to fix the problem

How to restore the sense of smell? You can take advice traditional medicine. The following remedies will perfectly help get rid of mucus:

• Take 150 grams of horseradish, grind it on a grater, add the juice of two or three lemons. You mix. Take one teaspoon twice a day on an empty stomach.
• A mixture of nose drops is prepared as follows: take mint and eucalyptus. Put everything in a liter jar, pour olive oil(it should cover the mixture). Leave until the mass becomes homogeneous. Drip twenty drops into each nostril in the morning and evening. Keep your head up for a few minutes. The resulting mixture should be stored in a dark place.

Removing mucus from the nose

After thinning the mucus, proceed to its removal, this is another step on the way to the return of smell. cook water solution. For these purposes, you can use salt, coniferous decoction. For each nostril you will need half a liter healing remedy. Rinse your nose thoroughly.

Now you know how to get your sense of smell back. This process is not very difficult, but rather lengthy. So be patient.

Let's talk about hyperosmia

A person can not only lose his sense of smell, but vice versa - to acutely feel all smells. Hyperosmia is a heightened sense of smell. Most often it appears in the following cases:

• In pregnant women.
• In people who have mental illness.
• With multiple sclerosis.
• With migraines, brain tumors.
• With infectious diseases.

This condition manifests itself as follows: sick people smell much more intensely than healthy people. For the treatment of hyperosmia, general strengthening therapy is used.

When is smell best?

You already know that smell is a feeling. Perhaps you are interested in who has it more developed. It has long been believed that the sense of smell is best developed in women. But more recently, scientists have come to the conclusion that the representatives of the beautiful half of humanity are better at classifying and recognizing odors, while men perceive aromas as a signal for action.

Age also affects the sense of smell. The best way to recognize smells is people during puberty. By the age of forty-five, this feeling begins to fade, and by the age of seventy, many no longer smell subtle aromas.

The weather also affects the sense of smell. In hot weather, odors are usually felt more strongly.

Conclusion

Smell - which makes our life beautiful and richer. It is given to people from birth and pleases them until old age. Thanks to him, humanity can enjoy every new day.

Of all the sense organs, the most important and significant role sight and hearing play a role in human life. Therefore, 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 7–8th 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. Fresh smells should reign in grocery supermarkets: 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. Near olfactory center there is a 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 the last decade, it has become clear that the main role in this process belongs to receptor proteins, whose molecules, interacting with 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. 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. Especially marked decline olfactory acuity is manifested in people older than 70 years, and sometimes 60 years. 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 household products. natural gas(which by itself does not smell of anything from a human point of view) specifically so that you can notice its leak by smell. 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 levels. 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" - allegorical image 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 an intimate relationship with a woman for a long time 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 men's axillary sweat is much higher than in women's. Studies have shown that the smell of androstenone can affect the physiological and emotional state of people, in particular, suppress the effect of synchronization of sexual cycles described above 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 different cultures can perceive the same odors differently. Such differences were revealed in a completely unique survey conducted in 1986 by the journal national geographic. 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 were 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 the US National Institutes of 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 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.

Causes olfactory disorder"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 injuries, and drug intoxication, and allergic reactions, and mutations, and beriberi (for vitamins A and B12), and salt intoxication 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, metabolic disorders, toxic effects drugs, nerve damage 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.