Which animals, fish and birds have the best eyesight. An open lesson on the world around them on the topic "sensory organs" The sense of smell is especially important for which animals

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 slight loss of the ability to feel and distinguish subtle smells negates the pleasure of the most delicious 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 of various organs and systems of the whole organism.

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 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 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 oil or musk, 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 were felt by people who participated in the excavations of the 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 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 human 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 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, we can say that the close relationship between long-term memory, emotions and smell suggests that smell is a powerful means of influencing the entire human body and its perception of the world as a whole.

In the forest, where the possibilities of vision are very limited, the importance of smell increases. It is necessary when looking for food, it helps to detect the enemy in time, to accurately choose a sexual partner, not to confuse members of your family with representatives of the same species of animals, to find out if they are healthy or sick, full or hungry. Finally, the sense of smell allows animals to exchange versatile information.

Chemical analyzers, and olfactory receptors are designed for chemical analysis of the environment, are owned by almost all living beings. Specialists divide chemoreceptors into two groups. Some of them are conditionally called contacts. They do not have high sensitivity and are intended for the analysis of substances dissolved in water. In everyday life, we call these receptors taste receptors, but when it comes to perceiving devices that are on the back and tail of catfish, on the paws of a fly, and in tropical cockroaches in such places, which is indecent to say, I want to call them something else. They are important in the search for and identification of food, but we will not talk about them here.

Another group of chemical receptors is conventionally called distant. In some animals, they have phenomenal sensitivity. A male silkworm feels the presence of a female if 1,000,000,000,000,000 air molecules contain one molecule of the odorous drug she secretes. This allows winged cavaliers to react to a female ready for breeding, being several kilometers away from her, and then to find her. The record for detection range is 11 kilometers!

There are absolutely reliable observations that four-legged cavaliers manage to detect ladies at greater distances based on the tracks left on the ground. One fox was not too lazy to run away on a date for 40 kilometers. It is clear that this is not a record. Finding a mate by scent when it's wedding time for foxes is not difficult at all: females do not rely on the reliability of tracks and add a lot of odorous marks. Once, in early spring, I followed the trail of a small, apparently young chanterelle, which pedantically, every 2-3 meters left a drop of urine on the snow, which had a strong and persistent smell.

In vertebrates, olfactory receptors are located in the nasal mucosa. Usually this part of the inner membrane contains a special pigment that gives it a yellow-brown color, so the olfactory lining is not difficult to distinguish from the non-olfactory epithelium. Its size and the total number of receptor cells provide fairly accurate information about the development and perfection of the sense of smell. In humans, the area of the olfactory lining is 3-5 square centimeters and contains about 6 million receptor cells, while in dogs it reaches 100 square centimeters and has 220 million perceiving elements. As a result, a dog's nose is a million times more sensitive than a human's.

The olfactory receptors of mammals lie at the bottom of the grooved pits. These are long cone-shaped cells with a club-shaped apex, on which there are flagella or finger-like outgrowths, immersed in a layer of mucus that covers the olfactory epithelium. There is an idea that each receptor cell is designed to detect some particular type of odor molecules.

It is believed that a person owns 7-14 types of receivers. Various combinations of information they send to the brain allow olfactory gifted people to recognize more than 10 thousand smells. It is close to the olfactory "ceiling". Calculations show that 14 types of sensing devices can provide identification of 16,384 odors. The rabbit probably has 24 types of receptors, and the dog 25-35. There is no certainty that all 24 rabbit indicators are present in a dog. After all, her plant smells are not interested. A large number of olfactory receptors is not always combined with a variety of types of receivers. In some male insects, up to 2/3 of the receptive cells are needed to detect odorous substances secreted by the female.

Specific receivers include hygroreceptors designed to detect water. The search for food occurs according to generalized features inherent in all its species. Bloodsucking mosquitoes find their prey by "sniffing" the carbon dioxide emitted by any animal, or amino acids such as lysine, which are invariably part of the proteins of vertebrates.

In insects, the olfactory organs look like hairs, setae, and thin-walled outgrowths with many pores in the shell, and sometimes they are a shallow fossa. They can be located on various parts of the body, but most often on the antennae. The number of olfactory organs and the number of receptor cells varies greatly not only in different animal species, but also in males and females of the same species. The worker bee has up to 6,000 lamellar olfactory organs on each of its small antennae. The female Saturnia polyphemus butterfly has 14,000 sensitive organs with up to 35,000 receptor cells, and the male has 70,000 organs and 150,000 cells!

The number of receiving elements, of course, affects the sensitivity. The location of the receptors is also important. U. flying insects, whose males search for females by smell, they are located on large feathery antennae. With these openwork structures, males, as it were, catch the air, which allows them to. they "find" the molecules of an odorous substance. Even if there are very few of them in the air, the receptor cells will catch up to a quarter of all those that have passed through the sieve. Accordingly, the antennae of males are much more impressive than females. Such antennas are owned by the Chinese oak peacock eye and other real silkworms, and from those living on the territory of our country - a large nocturnal peacock eye and pear saturnia, the largest butterfly of the domestic fauna, with a wingspan of up to 18 centimeters.

The olfactory analyzer is in some respects less reliable than the other sense organs. In contrast to light, which spreads almost instantly, and sound, which also travels through space at high speed, the smell spreads slowly. In addition, the intensity of the smell largely depends on the movement of air, therefore, it is very unstable. It is quite obvious that the male Saturnia, who went on a date to the bride, located at a distance of several kilometers from him, even having overcome 3-5 tens of meters of the way, is not able to determine whether the smell has become weaker or stronger. He simply flies against the wind, and if he strongly deviates to the side and enters the zone where the lady’s smell becomes weaker, he makes shuttle flights until he again falls into the air stream carrying her fragrant “calls”. He does the same when he is in close proximity to the female.

Using the sense of smell, primitive tetrapods are not able to determine where the game is, but if it smells strong, they understand that they are somewhere close and stubbornly searching until they find the prey. A strong smell causes a stronger arousal, and therefore a more active search. And only when the distance is less than a centimeter, the little salamander will accurately determine the location of the prey.

Higher quadrupeds navigate by smell better, especially if they follow the trail. After running 2-3 tens of meters, they clearly notice, of course, if the track is not too old, the smell intensifies or weakens. This allows them to choose the direction of pursuit. Well, if the trail is lost along the way, they try to find it with the help of shuttle combing the area. Predators behave in exactly the same way, having caught the presence of hidden game with their upper senses. And only in close proximity the sense of smell works flawlessly.

For communication, animals produce special biologically active substances. They are called pheromones. The odorous substance of the female, having discovered which, the winged cavaliers are ready to fly to the ends of the world, refers specifically to them. Depending on what they are intended for, odorous substances are produced year-round or only at certain periods of life. The sex pheromone of butterflies begins to be synthesized when the female sex products mature and she is ready to start breeding. In many tetrapods, primarily mammals, females distribute special scents. Female sex hormones or special substances produced under their influence, by which males unmistakably recognize females ready for reproduction, can smell.

Depending on the meaning of the transmitted information, odorous substances used for communication have varying degrees of strength. But even the most unstable ones last much longer than, for example, sound signals. The smell of the Saturnia butterfly, which can spread over a distance of several kilometers, should last at least an hour. Typically, these pheromones have a much greater resistance.

If we draw an analogy between human ways of communication and forms of communication in animals, it is appropriate to compare olfactory signals with written speech. Indeed, smell marks that retain their aroma for several days are used as a kind of announcement. And if it is required to extend the validity period of the notices, the animals systematically update them. They are usually addressed to members of the same species, but are usually understood by most animals living in the neighborhood, if they have a developed sense of smell. Smell marks are equally interesting for both enemies and potential victims of ad owners.

Most often, urine and feces are used for long-term ads. However, many animals have special glands. In antelopes they are near the eyes, in Indian elephants - in front of the ear, in predators near vibrissae, in goats and chamois - behind the horns, in camels - on the neck, in rabbits - under the chin, in chimpanzees and gorillas - under the armpits, in hyraxes - on the back, on the soles - on the sable, near the tail - on the foxes and badgers, on the thigh - on the platypus, on the forehead - on the flying squirrel. On the borders of their site, animals (I almost said - they put them) turn stumps, stones, bushes and trees into boundary pillars with the help of odorous substances. The odorous mark remains for several days. Sable marks only hunting trails, which he constantly uses, and hippopotamuses absolutely the entire area of \u200b\u200bhis possessions, scattering droppings over it.

Wild rabbits mark the boundaries of possessions with their paws, only it is more difficult for them to do this. The odorous gland is found only in males. Before starting to put marks, the head of the family rubs the soles of the front paws with a secret released from the glands. But after the animal ran for half a day on business and wiped its paws well on the grass and earth, you can safely go to your hole without fear that you will leave too noticeable a mark.

The feces of animals, whether they like it or not, spread the scent of the creatures that left them. Agree, this is not always convenient, since he will inform harmless creatures that they have entered the territory of a dangerous beast, and he will help predators to find the object of their hunt. To avoid such inconvenience, many animals arrange latrines located on the outskirts of their possessions, which are used by all members of the family or pack, and sometimes all the tribesmen living in the district, although for this they need to come from afar. Some creatures that are not able to move long distances, and therefore are especially interested in not attracting predators to their habitat, try to empty their bladder and rectum as rarely as possible, and so that the smell does not constantly renew, they synchronize the process of defecation by visiting toilets the whole family. Such rules are adhered to by sloths.

Create toilets and predators. Otters arrange them along the banks of lakes and rivers, most often on sandy beaches. Animals rake a mound 10-12 centimeters high with their paws and use it as a toilet bowl, leaving their excrement here. If the banks are overgrown with grass, any tubercle, small stone or stump can become a “toilet bowl”. On a sandy spit with an area of 4-8 square meters there can be up to 10 "pots". Often several members of the same or different families of otters use the toilet at once. A toilet once built serves several generations of animals. At cougars, toilets are located near lonely trees, rocks and other conspicuous objects. Not a single animal will pass in the toilet area without visiting it.

The point of public toilets seems to be that they allow members of the same animal species to exchange information. The smell of feces is able to tell about the food eaten, to tell which of the animals is starving and where the game is in abundance. Public toilets inform about the state of health and other features of the life of clients, allow you to find out who is who and who lives where. Such information, collected in advance, is necessary during the breeding season. They are especially important for such unsociable creatures as cougars, who avoid personal contact with relatives for most of the year, and besides, they own huge individual plots, that is, dispersed over a large territory. To make the information about the tribesmen exhaustive, the animals use several public toilets located in different areas.

The alarm signal, in order not to arouse the family or flock for a long time, should be short, and if the danger is not eliminated and after the destruction of the odorous substance, it is resumed. An attacked ant immediately releases an odorous substance. The smell in a few seconds spreads to 10-15 centimeters, and all members of the ant family who find themselves in this radius rush to the rescue. In different species of ants, the danger signal is valid from a dozen seconds to several minutes.

Ants also generate an alarm signal or a call for help while hunting. One of the species of South American ants, having found large prey, releases the pheromone of the mandibular glands. This is an invitation to comrades hunting somewhere nearby to take part in an attack on a dangerous enemy. The hunter can deal with the game alone, and gives the signal later to help him carry the "carcass" into the anthill. Each ant species uses its own pheromone as an alarm signal. In Odontomachus ants, it smells like chocolate. No wonder these ants respond so readily to a scented call.

It is convenient to mark temporary paths with an odorous substance. If the fire ant has found a lot of food, returning home, from time to time it touches the ground with its stinger, leaving a dotted odorous trail along which other ants will run for food. Fire ant road signs last only 100 seconds. During this time, the ant can crawl only 40 centimeters, but if there is a lot of food, many porters move towards the house, updating the signs all the time.

Ants from the genus Ponerin prey on termites. The scout, having discovered their underground gallery, hurries home and leaves a mobilization trail along the way. After about five minutes, he leaves the nest, accompanied by a group of large and small worker ants, and leads them on his trail. Having reached the place of hunting, large ants immediately begin to dig the ground, and small ones wait until a narrow gap is ready. They penetrate underground corridors, pull out dead termites from there and put them in piles. Ants do not make large holes so that large soldiers do not jump out through them - the formidable guard of the termite mound. After 10 minutes, the hunt ends, and the ants with rich prey go back. These ants smell the milestones of the road for more than 20 minutes. Termites also use scented markers to mark their exploration trails.

Animals living in herds, even quite large ones, apparently remember each other's individual smells, which allows them to maintain a certain stability of their collectives. In huge families of social insects, it is impossible to remember each of its members "by sight", and they use smell for identification. It acts as an identity card, or rather a pass.

Each family of social insects - bees, wasps, ants, termites - has its own common, unique smell. The guard will not let a stranger into the house. Insects, living together, involuntarily become impregnated with it, but the male rabbit has to specially mark his children. The male marsupial flying squirrel marks the female with its scent. The odorous mark is at the same time a wedding ring, a marriage certificate, and a new surname by her husband.

Chemical language is close to olfactory. Social insects like to discuss their affairs and issue “orders” on it. In families of ants with several castes, small workers nurse the children, and soldiers wander in search of food. Tiny larvae already know who will be who when they become adults. The older generation decides the fate of the youth. If there is a lot of food around, the soldiers successfully cope with their task, and well-fed queens lay many eggs. These families need nannies. On a full-fledged food, the larvae quickly grow up and reach adulthood, not having time to grow up, and therefore remain small working ants - nannies for life.

If there is not enough food for the ant family, hungry males and females begin to secrete a special substance that the nannies transfer to the larvae. This is a mobilization order, that is, an order for the larvae to become soldiers. The order will be fulfilled if it is brought to the attention of the larvae on the 45th-60th day after their last molt. "Recruits" can quickly establish a food supply, and this circumstance is important to foresee. To do this, the ant state needs to have accurate ideas about the size of its own army.

It can be judged by the concentration of a special substance emitted by each soldier. When the army reaches the limit, the concentration of this substance will reach a level that will allow the order to "recruit" to be canceled. It is interesting that this order will be clear to the larvae only on the 45th-60th day after the last molt.

Language is especially important for insects living in large families. They constantly have to exchange information, organize rallies and general meetings, at which they explain themselves with the help of strong chemicals. The nomadic ants of America - ecitons either live settled, or go on a two-three-week trip. With the onset of night, the ants line up in columns and, having taken all the belongings, larvae and pupae, go on a multi-day trip. How do they agree when to start the campaign, where to end it? And who gives the signal to speak?

It turns out that the growing larvae begin to secrete a special substance that the ant nannies lick and pass on to the rest of the family. This substance, like the signal of a bugle playing "campaign", makes ants want to roam. When they have eaten enough of it, they can no longer sit still, grab the larvae in their jaws and march on the march.

18-19 days will pass, the larvae will grow up, begin to pupate and stop excreting the “travel substance”. Ants calm down, make a stop and live sedentary until new larvae hatch from the eggs laid by the uterus and grow up, which will give a signal to go. Scientists have calculated that 10 stimulating chemicals are enough for the ant family, various combinations of which give them the opportunity to “discuss” any ant problems.

Smell and chemical language lends itself to imitation. It is widespread among animals to use other people's scents as fake IDs and false passes. Ants live in tropical countries, which do not build anthills themselves. An adult female crawls into the anthill of another ant species. The guards at the entrance let her through unhindered. She presents a false pass, secreting a substance similar to the uterine substance of the queen of the anthill, but acting even stronger. Therefore, worker ants begin to care for her, for her testicles, larvae, pupae. Gradually they stop recognizing their own queen and kill her.

The larva of the ground beetle shaumi secretes a substance similar to that of the termitary queen. Presenting false documents, she freely gets to the cell where the queen lives, and eats the hostess of the house. Now she will live in a strange house, surrounded by the attention of a huge army of termites that clean her and feed her. Termites themselves are staunch vegetarians. Such food does not quite satisfy the larva, and from time to time it diversifies the menu with its benefactors - termites.

Cats are typical nocturnal predators. For fruitful hunting, they need to use all their senses as much as possible. The "calling card" of all cats without exception is their unique night vision. The cat's pupil can expand up to 14 mm, letting a huge beam of light into the eye. This allows them to see perfectly in the dark. In addition, the cat's eye, like the moon, reflects light: this explains the glow of the cat's eyes in the dark.

All-seeing dove

Pigeons have an amazing feature in the visual perception of the world around them. Their viewing angle is 340o. These birds see objects located at a much greater distance than a person sees them. That is why, at the end of the 20th century, the US Coast Guard used pigeons in search and rescue operations. Sharp pigeon vision allows these birds to perfectly distinguish objects at a distance of 3 km. Since perfect vision is the prerogative of mainly predators, pigeons are one of the most vigilant peaceful birds on the planet.

Falcon vision is the most vigilant in the world!

The most vigilant animal in the world is the bird of prey, the falcon. These feathered creatures can track small mammals (voles, mice, ground squirrels) from great heights and simultaneously see everything that happens on their sides and front. According to experts, the most vigilant bird in the world is the peregrine falcon, capable of spotting a small vole from a height of up to 8 km!

The fish don't miss either!

Among fish with excellent eyesight, the inhabitants of the depths are especially distinguished. These are sharks, and moray eels, and sea devils. They are able to see in pitch darkness. This is because the density of rod placement in the retina in such fish reaches 25 million/sq.mm. And this is 100 times more than in humans.

horse vision

Horses see the world around them with peripheral vision because their eyes are located on the sides of their heads. However, this does not prevent horses from having a viewing angle of 350 degrees. If the horse raises its head up, then its vision will approach spherical.

high speed flies

Flies have been proven to have the fastest visual response in the world. In addition, flies see five times faster than humans: their frame rate is 300 images per minute, while humans have only 24 frames per minute. Scientists from Cambridge claim that the photoreceptors on the retina of fly eyes can contract physically.

40. Task. Write the names of the sense organs indicated in the figure by numbers.

1. Organ of hearing (ear)

2. Organ of vision (eye)

3. Organ of smell (nose)

4. Organ of taste (tongue)

5. Organ of touch (skin)

Task 41. Write down the shades of red and blue.

42. Task. Give examples of items of light green, lemon, cherry, pink, burgundy, brown colors.

Light green - lettuce;

Lemon - lemon;

Cherry - cherry;

Burgundy - beets;

Brown is wood.

Task 43. Explain why the sense of smell is better developed in carnivores than in herbivores?

Answer. In order to get their own food, predators have to either look for it on the trail, or is in ambush. Therefore, the sense of smell becomes the most important of the senses. In herbivores, the organ of vision comes first.

Practical work

Blindfold your eyes and try to walk around the class. What do you feel? Is it difficult for you to navigate? Express your guess: how do blind people navigate the world around them?

I feel great difficulty in moving, as I meet constant objects on my way. It is very difficult to navigate.

With the help of hearing, a person blind from birth receives the largest amount of information about the world. Living, he does not pay attention to forms, but he can recognize a friend by the steps, by the sounds of his voice. He learns about what he has to deal with through sounds.

Example. A man stopped in front of the blind man. With the help of hearing, he determines that he sat down on a chair, settled down on it more comfortably, sighed, moved his legs. Here he hears how the seated person began to pour water into a glass: the blind man learns about its fullness by the sound of the poured liquid.

He has an amazing memory for sounds. He finds an infinite number of shades in voices. And every sound, every intonation is of great importance for him!

A person born blind is familiar with objects only through touch. Touching objects with his hands, he cannot imagine how they look - he can only understand whether it is soft or prickly, dry or wet. With the help of fingers, he notes all the irregularities of the object, roughness, remembers them. Therefore, among all the cups of the tea service, he unmistakably determines his own.

The world of a person blind from birth consists of sounds, smells and hints of shapes. Without approaching the bouquet, without touching it with his hands, the blind can determine by smell what flowers it is made of. The smell gives the name to the flowers: rose he calls the smell of a rose, chamomile - the smell of chamomile.

Sitting at the dinner table, the blind-born can tell exactly what dishes are in front of him: his sense of smell is developed as exceptionally as his hearing, as well as his sense of touch.

Due to the fact that it is difficult for the blind to find lost things, they become friends of order. A blind person has an extremely highly developed memory.

The blind man sees with the help of his skin. This sheath possesses exceptional sensitivity in him. A blind person judges the proximity of fire by the degree of warmth; about the neighborhood of bodies - by the action of air on his face.

Task 44. Write down what taste these products have.

Lemon - sour;

Horseradish - bitter and burning;

Apple - sweet;

Mustard - bitter;

sauerkraut - sour;

Sugar is sweet;

Herring - salty;

Grapes - sweet;

Chocolate is sweet;

Garlic is bitter.

Practical work

1. Take half a teaspoon of sugar solution and hold it in your mouth for a while. Is there a difference in how you feel at the beginning and at the end of the experience?

Blindfold your eyes for a few seconds, hold your nose, and try some food you know. Do you recognize the taste of this product? Describe and explain your feelings.

Answer. There is a difference. At first, the taste is felt much sharper, then less sharp. This happens because the nerve signals begin to weaken, and the taste organs seem to “get used” to the new sensation.

I recognize the taste of the subject. But with a pinched nose, it is more difficult to do this, because usually a person remembers several sensations at once - taste, smell, color, and others. And when a person uses a limited number of sensory organs, recognition is slower.

2. We recognize the object by touch. Close your eyes, take an object in your hand. Determine what it is, what material this item is made of.

Answer. I recognize objects by touch by surface, volume, shape - everything that is perceived by the organs of touch.

Task 45. Write down what sounds these objects make.

Door - creaks;

It thunders;

Rain - knocking;

Children scream;

Mouse - squeaks;

The baby is crying;

Wind - whistles;

The cat is meowing.

Task 46. Mark the correct statement.