Names of human sense organs. The main sense organs in humans

Sense organ

Sense organ- specialized peripheral anatomy physiological system, which provides, thanks to its receptors, the receipt and primary analysis of information from the surrounding world and from other organs of the body itself, that is, from external environment and internal environment organism.

Distant sense organs perceive stimuli at a distance (for example, organs of vision, hearing, smell); other organs (taste and touch) - only with direct contact.

Some senses can complement others to a certain extent. For example, a developed sense of smell or touch can to some extent compensate for poorly developed vision.

Human sense organs

The information received by the human brain from the senses forms the perception of the world around him and himself.

There is an opinion that there is a sixth sense:

• vestibular apparatus (sense of balance and position in space)

Information about stimuli affecting the receptors of the human senses is transmitted to the central nervous system. It analyzes the incoming information and identifies it (there are sensations). Then a response signal is produced, which is transmitted along the nerves to the corresponding organs of the body.

The pathways from the sense organs in humans are the vestibular, auditory, visual, olfactory, tactile and gustatory pathways of the central nervous system.

It is generally accepted that a person has four more senses:

Thermoception is the feeling of warmth (or lack thereof) on our skin.

Equibrioception is a sense of balance, which is determined by the fluid-containing cavities in our body. inner ear.

Nociception is the perception of pain by the skin, joints, and organs of the body. Strangely, this does not include the brain, which has no pain-sensing receptors at all. Headaches - no matter what we think - do not come from within the brain.

Proprioception - or "body awareness". It is an understanding of where the parts of our body are, even we do not feel or see them. Try closing your eyes and swinging your leg in the air. You will still know where your foot is in relation to the rest of your body.

Sense organs in animals

Reaction to external influences(light, temperature, chemical substances and other irritants) lower organisms usually caused not by special organs, but common property living matter - irritability.

At higher organisms information is perceived and transmitted by specialized sense organs adapted to the perception of signals of a certain nature.

In the process of evolution, animals have developed sensory organs specific to their lifestyle, such as electroreception, pressure sensation, thermoreception, sensation magnetic field Earth.

see also

Notes

Literature

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See what the "Sense Organ" is in other dictionaries:

sense organ- nervous devices that serve as receivers of signals informing about changes in the external environment (exteroception) and in the body of the subject (interoreception). It is customary to distinguish five external sensory systems of sight, hearing, smell, taste, skin ... ...

A concept synonymous with the concepts analyzer, sensory system. There are five sense organs: the organ of sight, the organ of hearing, the organ of taste, the organ of smell, the organ of touch. This list can be expanded at the expense of others morphologically and functionally ... ... Psychological Dictionary

Exist., number of synonyms: 5 eyes (65) skin (62) nose (57) ears ... Synonym dictionary

- (o. sensuum) O., carrying out the perception and primary analysis of irritations coming from the environment ... Big Medical Dictionary

Sense organ- the same as the Analyzer, sensor system ... Dictionary of trainer

sense organ: specific energy concept- see the concept of specific energy. Dictionary practical psychologist. Moscow: AST, Harvest. S. Yu. Golovin. 1998 ... Great Psychological Encyclopedia

Complex anatomical structures, perceiving and analyzing various irritations of the external and internal environment. Each analyzer consists of three parts: peripheral (receptors), which perceives the energy of external stimulation and ... ... medical terms

SENSOR, ANALYZER- (sense organ) a complex of anatomical structures that perceive and analyze various irritations of the external and internal environment. Each analyzer consists of three parts: peripheral (receptors), which perceives the energy of the external ... ... Dictionary in medicine

The sense organ, which has developed in the process of evolution, is a specialized peripheral anatomical and physiological system that, thanks to its receptors, provides for the receipt and primary analysis of information from the outside world and from other organs of itself ... ... Wikipedia

Vomeronasal organ (vomeronasal organ, Jacobson's organ, sometimes also vomer) is the peripheral part of the additional olfactory system of some vertebrates. Its receptor surface is in the path of inhaled air ... ... Wikipedia

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Probably, in the first period of the existence of life on Earth, our planet seemed to living beings as a completely dark, soundless world. Gradually, they learned to feel smells, taste, heat and cold, touch, thereby acquiring touch, smell, taste - the first external senses. With their help, ancient organisms searched for food, escaped from dangers. Gradually, the world of colors and sounds opened up to the first creatures. Animals acquired a protective coloration, learned to quietly sneak up on prey or hide from the enemy. Their perception became more and more perfect, the world of living nature perceived by them became more and more diverse.

Imagine that a person is standing on the seashore. The wind throws salt spray in his face. In front of him is an endless blue and a golden sun.
He listens to the sound of the sea, inhales its unique smell. A person feels strong and happy, feels every muscle, his whole body, standing firmly on the ground. A single image is born in his brain - the sea, which he will never forget.

1. ORGANIZATION OF VIEW

Through the organ of vision, a person receives the largest amount of information in comparison with other sense organs. “A tight fishing net, thrown to the bottom of the eyecup and catching the sun's rays” - this is how the wise Greek Herophilus imagined the retina of the eye. The retina, as the scientist proved, is precisely the network and precisely the catching ... separate, unified and indivisible quanta of the radiant energy of the Sun. The quantum nature of absorption and the appearance of radiation has now been established for the entire range of the electromagnetic spectrum. For the first time, the hypothesis about the occurrence of radiation by portions of energy was expressed in 1900 by the scientist Planck (1858-1947)

In terms of sensitivity, the eye approaches an ideal physical device, because. it is impossible to create a device that would register the energy of less than one quantum.

Where h is Planck's constant, equal to 6.624 * 10-27 erg * s
v - radiation frequency, s-1

This unique property eyes benefited scientists - pioneers of atomic and nuclear physics. For centuries, science has been studying the eye, discovering all its new properties and secrets. An unsolved mystery, one of the most difficult and unexplored problems of modern physiology of the sense organs is color vision. It is completely unknown how the brain decodes the color signals that come to it.

The eye is a complex optical system. Light rays enter the eye from surrounding objects through the cornea. The cornea in the optical sense is a strong converging lens that focuses divergent different sides light rays. And optical power the cornea does not change and always gives a constant degree of refraction.
The sclera is opaque outer sheath eyes, respectively, she does not take part in conducting light inside
eyes.
It has been proven that the optics of the eye is just a window into which light quanta fly; that the retina of the eye and the brain make the resulting image clear, voluminous, colored and meaningful

But the human eye cannot perceive radiation in excess of high intensity and distinguish between short signals (up to 0.05 s long).
It is considered that the average human eye in average daylight conditions, it perceives an extremely narrow (compared to the spectrum of possible radiation) wavelength range: from 380 to 780 nm (1 nanometer = 10-9m) or (0.38 × 0.78 μm).
The resolving power of the eye is also very small: the minimum size of an object that can be distinguished by the eye turns out to be about one micrometer (10-6m). That's why We don't see the world as it really is., and new methods and ideas of physics, mathematics, chemistry, biology are the key to future discoveries in this area.

2. ORGANS OF HEARING. SOUND. RESONANCE THEORY OF HEARING

The world is filled with a wide variety of sounds. The noise of the wind and waves, thunder and the chirping of grasshoppers, the singing of birds and the voices of people, the cries of animals and the sounds of traffic - all these sounds are picked up by the auricle and cause vibration eardrum.

The human ear consists of three parts: outer, middle and inner, the structure of each of which, in turn, is a rather complex system. Let's try to figure this out together complex process which we call "hearing".
With the help of the auricle, we determine the direction from which the sound comes. The external auditory meatus is an elongated canal, the walls of which produce a liquid substance, better known to us as sulfur. It is designed to remove foreign bodies and preventing the ingress of various insects due to the specific smell. Due to the depth of the external auditory meatus, the temperature and humidity at the tympanic membrane remain almost constant, and the latter retains its mobility. At the same time, the eardrum is well protected from any damage.

Frequency range of sounds perceived by the ear 16-20 to 20000 Hz

Speech frequency range 1200-9000 Hz

The frequency of sound vibrations to which the ear is most sensitive is 1500-3000 Hz

Through the system of sound ossicles of the middle ear, sounds are converted into impulses and transmitted to the perceiving cells of the brain.
How exactly the brain decodes these impulses and “recognizes” the sounds is still unclear to scientists.

But the sounds perceived human ear, are an important source of information, make it easier to adapt to the world around. What is sound, how it arises, propagates, its parameters are studied by a special department of physics - acoustics.
Sound or a sound wave can propagate only in a material environment; it is an elastic wave that causes auditory sensations in a person. More than 20,000 filamentous receptor endings located in the inner ear convert mechanical vibrations into electrical impulses, which are transmitted through 30,000 fibers of the auditory nerve to the human brain and cause auditory sensations. We hear air vibrations with a frequency of 16 Hz to 20 kHz per second. 20,000 vibrations per second is the highest sound of the smallest wooden instrument in the orchestra - the piccolo flute, and 16 vibrations corresponds to the sound of the lowest string of the largest bowed instrument - the double bass.
fluctuations vocal cords can create sounds in the range from 80 to 1400 Hz, although record low (44 Hz) and high (2350 Hz) frequencies are recorded.

It has been proven that the length and tension of the vocal cords determines the pitch of the singer's voice. For men, it is (18 × 25) mm (bass - 25 mm, tenor - 18 mm), a in women - (15?20) mm.
In a telephone, for example, a frequency range from 300 Hz to 2 kHz is used to reproduce a human voice. The frequency range of the main oscillation modes of some instruments is shown in the figure:

The first truly scientific theory of hearing was the theory of the remarkable German naturalist, physicist and physiologist Hermann Helmholtz. It is called the resonance theory, it was confirmed by hundreds of experiments conducted by many scientists. But in last years, with the help of an electron microscope, some inaccuracies of this theory were revealed, in particular, in the perception of high and low sounds. Helmholtz and the Italian Corti are considered pioneers in the study of hearing, although they took only the first steps. Over the past 100 years, a considerable path has been traveled towards understanding the science of hearing, now we are talking about refining and developing it further. After all, any scientific theory must develop, bring new facts to people. Thus, the range of perception of the hearing organs is limited by small threshold possibilities for the perception of low and high sound intensity, as well as by a small frequency range of perceived sounds.

3. SKIN SENSORS

Surprisingly nice to expose your face to the fresh wind! On the face, lips, there are many special cells that feel both the coolness of the wind and its pressure. The skin is not only our protection, but also a huge source of information about the world around us, moreover, the source is very reliable. Often we do not believe our ears and eyes, but feel the object - we want to make sure that it is, to find out how it feels to the touch. For all these sensations, there are specialized cells, unevenly "scattered" throughout the body.
The ear perceives only sound, the eye perceives light, and the skin perceives touch and pressure, heat and cold, and finally pain. The main skin sense is touch, the sensation of touch. The tip of the tongue, lips and fingertips are most sensitive to pressure and touch. For example, on the skin of the fingertips, the sensation of touch occurs at a pressure of only 0.028 - 0.170 g per mm2 of skin. Not all skin feels touch, but only its individual points, of which there are about half a million. At each point there is a nerve ending, so even the slightest pressure is transmitted to the nerve and we feel a light touch.

The organs of touch do not allow distinguishing weak stimuli and rather small roughness from each other.
The concentration of harmful liquids on the skin and the range of temperature perceived by a person is small and provides only a regime for the biological survival of the organism.

3.1. ELECTRICAL RESISTANCE OF BODY TISSUES

Electrical resistance individual sections tissues depends mainly on the resistance of the skin layer. Through the skin, the current passes mainly through the sweat channels and, in part, sebaceous glands; the current strength depends on the thickness and condition of the surface layer of the skin.
Skin is the outer covering of the body. Its area is about 2 m2. The skin is made up of three main layers. The outer layer - the epidermis - is formed by a multilayer epithelial tissue, which is constantly desquamated and updated due to the reproduction of more deeply located cells. Below the epidermis is a layer connective tissue- dermis. Numerous receptors, sebaceous and sweat glands, hair roots, blood vessels and lymphatic vessels. The deepest layer subcutaneous tissue- formed by adipose tissue, which serves as a "cushion" for organs, an insulating layer, a "warehouse" nutrients and energy.
The main function of the skin is to protect against mechanical influences, an obstacle to the ingress of foreign substances, pathogenic microbes into the body.
Electrical resistance human body It is determined mainly by the resistance of the superficial stratum corneum of the skin - the epidermis. Thin, delicate and especially sweaty or moist skin, as well as skin with a damaged outer layer of the epidermis, is a good conductor of electricity. Dry, rough skin is a very poor conductor. Depending on the condition of the skin and the path of the current, as well as the value of the voltage, the resistance of the human body ranges from 0.5-1 to 100 kOhm.

4. THE ORGANISM OF SMELL

How can you describe the smell of freshness, how can you explain the difference between the smell of a rose and a rotten egg? You can describe it if you compare it with another familiar smell! There are physical instruments for measuring the strength of current and the strength of light, but there is no measure by which it would be possible to determine and measure the strength of the smell. Although such a device is very necessary for modern chemistry, perfumery, food industry and many other branches of science and practice.


We know surprisingly little about the natural olfactory organ, the odor-catching organ.

There is still no theory of smell perception, there is no law. So far, there are only experiments and scientific hypotheses, although the very first step towards understanding the smell was taken 2 thousand years ago. The great Lucretius Car proposed an explanation for the sense of smell: every odorous substance emits tiny molecules of a certain shape.

5. ORGANE OF TASTE

Taste is a complex concept, not only the tongue feels “delicious”. The taste of fragrant melon also depends on its smell. The tactile cells in the mouth provide a new taste flavor, such as the astringent taste of unripe fruit.

Taste in the mouth is perceived by taste buds - microscopic formations in the mucous membrane of the tongue. A person has several thousand of them in his mouth. Each bulb consists of 10–15 taste cells located in it like orange slices. Experimenters have learned to register a weak bioelectric reaction of individual taste cells by introducing the thinnest microelectrode into them. It turned out that some cells react to several tastes at once, while others only respond to one.

But it is not clear how the brain understands all this mass of impulses that carry information about taste: bitter or sweet, bitter-salty or sour-sweet. The first classification of tastes was proposed by M. V. Lomonosov. He counted seven simple flavors, of which only four are now generally accepted: sweet, salty, sour and bitter. These are simple, most primary tastes, they have no aftertaste. Different areas of the tongue in a person sense taste differently.

At the tip of the tongue there is a cluster of "sweet" bulbs, so sweet ice cream should be tasted with the tip of the tongue. The back edge of the tongue is responsible for the acid, and its front edge is responsible for the salt. Bitter radish feels the back wall of the tongue. But we feel the taste of food with our whole tongue. Along with the bitter medicine, the doctor ascribes some other one that beats off the unpleasant taste, because. from two tastes you can get a third, not like either one or the other. The most important problem of the science of taste is to find the relationship between the molecular structure of the taste cell, the physicochemical nature of the substance and the taste itself. And to the question: "What is the limited range of perception of the organ of taste?" it can be answered that for him the nature of the sensitivity to only a limited set of substances and chemical compounds consumed by the human body. But man is a biological being, all his sense organs were formed during a long evolution, so the range of their perception was sufficient to adapt to life in earthly conditions. But the narrow range of perception of the sense organs in comparison with the variety of natural information signals has always been a brake on the development of scientific ideas about the world around us.

But man is a biological being, all his sense organs were formed during a long evolution, therefore the range of their perception was sufficient for adaptation to life in earthly conditions. But the narrow range of perception of the sense organs in comparison with the variety of natural information signals has always been a brake on the development of scientific ideas about the world around us.

6. SENSE ORGANS AND THE PROCESS OF KNOWLEDGE

A person receives a limited amount of information from each sense organ. Therefore, the process of cognition of the surrounding world can be compared with the situation that arose in the parable of the five blind men, each of whom tried to imagine what an elephant is.
The first blind man climbed onto the elephant's back and thought it was a wall. The second, feeling the elephant's leg, decided that it was a column. The third picked up the trunk and mistook it for a pipe. The blind man who touched the tusk thought it was a saber. And the last one, stroking the elephant's tail, thought it was a rope.

Similarly, the lack of sensory perceptions leads to contradictory and ambiguous ideas about the structure of the surrounding world. Life experience turns out to be insufficient in the study of phenomena determined by time intervals and spatial dimensions that are inaccessible to observation. Under such conditions Additional Information obtained by experimental facilities, which can be used to expand the range of received signals, and by paradoxical physical theories that describe the basic laws of physical phenomena.And, despite the limited range of perception, a person is trying to determine the structure of matter and understand the nature of numerous effects outside the vibration ranges accessible to the senses.

With the help of these organs, we get an idea of environment. Five separate systems respond to different stimuli: the eyes allow visual information to be received; ears catch sound vibrations and participate in the regulation of balance; nose and tongue identify smells and taste sensations respectively, and sensory nerve endings in the skin allow us to sense touch (the sense of touch), temperature changes, and pain.

The organs of vision are the eyes, which in the embryo develop from two "kidneys" formed from the brain. The captured image in the form of nerve signals is sent to the brain, where they are decoded and create visual perception. The eye is directed to the object of vision by six separate muscles that rotate it in different directions. Visual acuity depends on the refraction, or light refractive power, of the lens and cornea. Rays of light entering the eye are focused on the retina, and an image is formed on it.

Irritation nerve cells in the retina causes the formation of different impulses according to the brightness of light and color, which are deciphered by the brain, where a visual image is created. The bright spot in the photo on the right is the so-called optic disc, where all the nerve endings of the retina are collected in the optic nerve, which extends from the eye to the brain. You can also see the arteries that diverge from the disk and supply blood to the retina and other parts of the eye.

Hearing

The auricle not only protects the ear from damage, but also acts as a receiving device that directs sound vibrations to the eardrum.

The ear, consisting of the outer, middle and inner sections, is not only an organ of hearing, but also determines the position of the body and balance. The outer ear is Auricle which protects the ear canal from damage. For protection against foreign particles in ear canal there are also hairs and special glands that secrete sulfur. The middle ear contains the three smallest bones in the body: the malleus, anvil, and stirrup, which connect the tympanic membrane to the inner ear, which contains the cochlea, the organ of hearing. The vibrations of the tympanic membrane are converted into nerve impulses that the brain perceives as sound.

The nasal passages are connected with three pairs of sinuses (air-filled cavities of the skull). The sensitive endings of the olfactory nerves, similar to hairs, protrude into the nasal cavity. They pick up and detect odors in the air, relaying information to the olfactory bulbs, which are directly connected to the brain.

Odors are detected by hair-like olfactory nerves that protrude into the nasal cavity at the top of the nose and capture and analyze the molecules in the air we breathe. The sense of smell may be disturbed by smoking or temporarily impaired by colds or allergic diseases. Permanent loss of smell can occur due to nerve damage (for example, with a skull injury) or as a result of damage to the part of the brain that analyzes smells.

organs of taste

The main taste buds are the taste buds located in the protruding papillae on the upper surface of the tongue. They are able to distinguish only four basic taste sensations: sweet, sour, salty and bitter. The taste buds that determine each of these sensations are located in certain areas of the tongue. Taste is closely related to the sense of smell, which helps us to capture a wide variety of aromas. Loss of the sense of smell usually leads to a deterioration in taste sensations; some medicines have the same effect, and sometimes a lack of zinc in the body.

AT different areas tongue, specific taste sensations are determined: in the back - bitter, on the sides - sour, in the front - salty and at the tip - sweet.

The sense of touch is associated with specific receptors that are immersed in the thickness of the skin at different depths. Free nerve endings respond to touch slight increase temperature and cold. Some closed nerve endings instantly respond to pressure, others to vibration and stretch. Thermoreceptors respond to sensations of heat and cold and transmit signals to the hypotapamic region of the brain about the need to regulate body temperature.

Under the sense of touch is understood all skin sensations that are transmitted along the nerves from sensitive nerve endings located in the skin. Different kinds receptors determine different sensations. The number of receptors varies from one area of ​​the body to another: for example, there are many nerve endings in the fingertips and around the mouth, while there are very few in the skin of the middle back. The sense of touch may be impaired by local traumatic damage to skin receptors or by diseases that affect nerve fibers, the peripheral nervous system, and/or the brain.

The main signs of a disease of the sense organs

The main symptom of a violation of any of the senses is a partial or complete loss of sensitivity. Depending on which of the sense organs is affected, pain or other symptoms of the disease may also occur.

The sense organs are specialized structures through which parts of the brain receive information from the internal or external environment. With their help, a person is able to perceive the world.

Sense organs - afferent (receptor) department of the analyzer system. The analyzer is a peripheral part reflex arc, which communicates between the central nervous system and the environment, accepts irritation and transmits it through the pathways to the cerebral cortex, where information is processed and a sensation is formed.

5 human senses

How many main sense organs does a person have?

In total, it is customary for a person to share 5 senses. Depending on the origin, they are divided into three types.

• The organs of hearing and vision come from the embryonic neural plate. These are neurosensory analyzers, refer to first type.
• The organs of taste, balance and hearing develop from epithelial cells that transmit impulses to neurocytes. These are sensory-epithelial analyzers, they belong to second type.
• Third type includes peripheral parts of the analyzer that sense pressure and touch.

visual analyzer

The main structures of the eye: the eyeball and auxiliary apparatus (eyelids, muscles of the eyeball, lacrimal glands).

Eyeball has an oval shape, is attached with the help of ligaments, can move with the help of muscles. Consists of three shells: outer, middle and inner. Outer shell (sclera)- this is protein shell opaque structure surrounds the surface of the eye by 5/6. The sclera gradually passes into the cornea (it is transparent), which is 1/6 of the outer shell. The transition region is called the limbus.

Middle shell consists of three parts: choroid, ciliary body and iris. The iris has a colored color, in the center of it is the pupil, due to its expansion and contraction, the flow of light to the retina is regulated. In bright light, the pupil constricts, and in low light, on the contrary, it expands to catch more light rays.

Inner shell is the retina. The retina is located at the bottom of the eyeball, provides light perception and color perception. The photosensory cells of the retina are rods (about 130 million) and cones (6-7 million). Rod cells provide twilight vision (black and white), cones serve for daytime vision, color discrimination. The eyeball has inside the lens and chambers of the eye (anterior and posterior).

The value of the visual analyzer

With the help of the eyes, a person receives about 80% of information about the environment, distinguishes colors, shapes of objects, and is able to see even with minimal light. The accommodative apparatus makes it possible to maintain the clarity of objects when looking into the distance, or close reading. Auxiliary structures protect the eye from damage, pollution.

auditory analyzer

The organ of hearing includes external, middle and inner ear, which carry out the perception of sound stimuli, generate an impulse and transmit it to the cortex of the temporal zone. The auditory analyzer is inseparable from the organ of balance, therefore the inner ear is sensitive to changes in gravity, to vibration, rotation, and movement of the body.

outer ear It is divided into auricle, ear canal and tympanic membrane. The auricle is an elastic cartilage, with a thin ball of skin, that determines the sources of sound. The structure of the external auditory canal includes two parts: cartilaginous at the beginning and bone. Inside are glands that produce sulfur (has a bactericidal effect). The eardrum receives sound vibrations and transmits them to the structures of the middle ear.

Middle ear includes tympanic cavity containing the hammer, stirrup, anvil and Eustachian tube(connects the middle ear with the nasal part of the pharynx, regulates pressure).

inner ear divides into a bony and membranous labyrinth, with perilymph flowing between them. The bony labyrinth has:

• vestibule;
• three semicircular canals (located in three planes, provide balance, control the movement of the body in space);
• snail (it contains hair cells, which perceive sound vibrations and transmit impulses to the auditory nerve).

The value of the auditory analyzer

Helps to navigate in space, distinguishing between noises, rustles, sounds at different distances. With its help, information is exchanged when communicating with other people. From birth, a person hears oral speech learning to speak on his own. If there are congenital hearing impairments, then the child will not be able to talk.

Receptor cells are found in the back of the upper nasal passages. Perceiving odors, they transmit information to the olfactory nerve, which delivers it to the olfactory bulbs of the brain.

With the help of smell, a person determines the good quality of food, or senses a threat to life ( carbon monoxide, toxic substances), pleasant aromas cheer up, the smell of food stimulates the production of gastric juice, promoting digestion.

organs of taste

On the surface of the tongue are papillae - these are taste buds, on the apical part of which there are microvilli that perceive taste.

The sensitivity of receptor cells to food products different: the tip of the tongue is susceptible to sweet, the root to bitter, central part- to salty. Through the nerve fibers, the generated impulse is transmitted to the overlying cortical structures of the taste analyzer.

sense organs

A person can perceive the world around him through touch, with the help of receptors on the body, mucous membranes, and in the muscles. They are able to distinguish between temperature (thermoreceptors), pressure levels (baroreceptors), and pain.

Nerve endings have high sensitivity in the mucous membranes, earlobe, and, for example, the susceptibility of receptors in the back is low. The sense of touch makes it possible to avoid danger - to remove the hand from hot or sharp object, determines the degree pain threshold, indicates an increase in temperature.

We continue a series of Internet lessons on the world around us. Let's talk today about the senses. Probably, in the first period of the existence of life on Earth, our planet was a completely dark and silent world for living beings. Gradually, they learned to feel smells, taste, touch, heat and cold, thereby acquiring touch, smell, taste. With their help, ancient organisms searched for food, escaped from danger...

Gradually living beings opened the world of colors and sounds. Animals began to acquire a protective coloration, they learned to quietly sneak up on prey or hide from the enemy. Their perception became more and more perfect, more and more diverse - the world of colors, sounds, smells of wildlife perceived by them.

The person has five senses - hearing, sight, smell, taste, touch . With their help, a person receives information about the world around him. A special organ is responsible for each of the senses. Name them...

It is true that the organ of sight is the eye, the organ of hearing is the ear, the organ of taste is the tongue, the organ of touch is the skin, and the organ of smell is the nose. And now about each in more detail.

Organ of vision - eye

Eyes- the most perfect and most mysterious organs in our body.

It is said that “it is better to see once than to hear a hundred times”. With the help of vision, a person receives 90% of information about the world around him. With its help, a person sees light, determines the color, shape and size of objects, their movement.

The eyes are located in eye sockets - special cavities of the skull. The eye is very important body and needs protection. Eyebrows and eyelashes protect it from sweat and dust.

Eyelids like car wipers. Approximately 25 times per minute a person moves his eyelids - blinks. This cleans the open part of the eye from dust and specks, moistens, protecting it from drying out. In this they are helped by the lacrimal fluid washing the cornea.

The eye itself is also called eyeball (for your form) or vitreous body . back wall"Apples" are lined with a black film - retina.

The front of the eye is protected by a transparent cornea. Under the cornea is a colored iris (iris), it is her color that determines the color of the eyes. The iris controls the amount of light entering the eye. In the center of the iris is a hole called pupil.In the dark, the pupil dilates to let more into the eye, and narrows in bright light.

Behind the pupil is lens lens-like eyes. Passing through the lens, light rays reach retina.The retina is as important to the eye as film is to a camera. It consists of light-sensitive cells, each of which sends its own signal along optic nerve in the cerebral hemispheres.From these signals, our consciousness adds up the image and gets an idea about the subject.

Did you know that there are two types of light-sensitive cells in the retina. Some distinguish colors, but only with sufficient light. Others perceive the world in shades of gray, but they are more sensitive to light. That is why for us "at night all cats are gray."

The structure of the eye from 4.05 to 7.24 and 10.09 to 11.09

And you know that...

• You see with your brain, not your eyes. The function of the eyes is to gather relevant information about the object you are looking at. This information is then sent to the brain. All information is analyzed in the brain.
• In daylight or too cold, the color of a person's eyes may change.
• There are approximately 1% of people on Earth who have the color of the iris of the left and right eyes is not the same.
• The simplest gymnastics for the eyes: "Butterfly". Blink frequently. It turns out that in front of the monitor, the eyes are lazy and stop blinking, and this harms our vision.
• The human eye distinguishes only seven primary colors - red, orange, yellow, green, blue, indigo and violet. But other than that, the eyes ordinary person able to distinguish up to a hundred thousand shades, and the eyes of a professional (for example, an artist) up to a million shades.
• Indian yogis treat their eyes by looking at the sun, stars and moon. They believe that there is no light equal in strength to the sun. This exercise is best performed at sunrise or sunset. But you shouldn't look at it at noon.
• The computers of the future will be able to control eye movements. Instead of a mouse and keyboard, as it is now.
• Paradox, but speed reading eye fatigue is less than with slow.

It's incredible, but the brain can be deceived ... such deception is called optical illusions or optical illusion. For example, look at the following pictures...

Are they moving? But it only seems to us, in fact, they are simply drawn.

Hearing organ - ear

A lot of information a person receives through hearing. These are sounds made by objects of inanimate and living nature, and human speech. Through hearing, a person learns about a danger that he does not see, for example, about an approaching car.

The ear is the second most important sense organ in the human body. If you close your eyes, you will still feel where the top is, where the bottom is, the chair leaned to the right or left. This is signaled by the balance organs in the inner ear. Means The ear is the organ of hearing and balance. .

What we usually call the ear is outer ear or Auricle . It picks up sounds and directs them into the auditory canal, which ends tympanic membrane .

Behind it is a cavity. middle earco auditory ossicles. Sound vibrations in the air cause the eardrum to vibrate. They are amplified by the auditory ossicles and are transmitted further - in inner ear (cochlea) filled with liquid. The liquid makes sensitive hairs vibrate. From them to auditory nerve a message about the sound is transmitted to the brain.

Due to the fact that there are two organs of hearing, we not only feel sounds, but also determine where the source is.

The inner ear has organ of balance (vestibular apparatus).

The sense of balance is the ability to determine the position of the body in space, that is, to distinguish between up and down. Thanks to this feeling, we walk without falling. But if being for a long time on the rocking deck of the ship, then the sense of balance is dulled: dizziness occurs. This condition is called seasickness.

And you know that...

• Loud music is harmful to hearing. This is a problem not only at concerts, but also in your headphones. By the way, listening to music through headphones increases the number of bacteria by 700 times.
• Ears are self-cleaning. Pores in ear canal produce earwax, and small hairs called cilia push it out of the ears.
• The smallest sound you can hear is 0 decibels. Volume level jet engine is 120 decibels. If you are exposed to 90 decibels or more for 8 hours, your hearing may be damaged. The figure shows a scale with decibels of sound (sound power). The redder the scale, the higher the decibels, which means the sound is dangerous to hearing.

• The sound of the raging ocean that we hear when we apply sea ​​shell to the ear is not the ocean, but the sound of blood running through the veins in the ear.

Olfactory organ - nose

Why does a person need to smell? It informs about the properties of the inhaled air, helps digestion, promotes the secretion of saliva and digestive juices, and therefore preserves health. The sense of smell also warns a person about danger, for example, in the event of a gas leak, in case of fire.

The organ of smell is the nose. Inside the nose is a mucous surface, and on it are millions of nerve fibers. Many small particles are separated from various objects that float in the air. These imperceptible particles fall on the nerve fibers of the nose and irritate them. This irritation is transmitted to the brain, to a special center where the sensation of smell is formed. Particles of different substances irritate nerve fibers in different ways, so a person distinguishes odors.

Humans have many associations with odors. The sense of smell is most acute in summer and spring, especially in warm and humid weather. In the light, the sense of smell is sharper than in the dark.

Do you know that if a person loses his sense of smell, then food loses its taste for him, and such people are more likely to get poisoned, because they cannot identify low-quality food.

The sense of smell is inseparable from the substance itself. There are up to 400 thousand different odors perceived by humans. Note that there is still no scientific classification of odors and they are named according to the substance that emits them “herbs”, “rose smell”, etc.

We only smell when we breathe in. Bring an odorous substance to your nose. At normal breathing you will smell it. Hold your breath for a while, and you will not smell, although the source of it is at the very nose. Make several sharp short sniffing movements. They are especially favorable for the work of the olfactory organ, which is located in the uppermost part of the nasal cavity.

And you know that...

• A dog has 230 million olfactory cells in its nose, while humans have 10 to 11 million, which is twenty times less. However, the dog cannot find anything that does not smell at all.
• People's favorite smells are fresh bread, freshly cut grass and coffee. The smells of rolls and coffee not only excite the appetite, but also increase the desire to buy. Therefore, in large stores it often smells of coffee and fresh pastries.
• A person who lives among a noisy civilization does not feel up to 70% of urban smells. But, for example, an African who lives in wild nature, is able to catch the smell of his friend who passed along the forest path a few hours ago.

The organ of taste is the tongue

Experiment #1

In front of you are three glasses with a yellowish liquid? What could it be? Do you have enough sense organs - sight, hearing, nose? If not, try to decide what to do….

That's right, you need to try the juice, that is, which sensory organ to turn on? That's right, this TASTE.

There are billions of products on earth and everyone has their own taste. Incredibly, a person is able to distinguish all shades of this diversity.

To begin with, let's find out, FOR WHAT is it given to a person to feel the taste?

When you were very, very young, you were real explorers. Anything that attracts the attention of babies immediately goes into the mouth.

Thus, children try to get information about the objects they encounter. Babies are already capable of recognizing taste.

Taste is necessary for a person to recognize chemical composition any substance that enters. Means, taste is the protector of the body . Taste is the only sense organ on which our life directly depends!

By the way, everything seemed curious to our distant ancestors: the taste suggested what you could eat and what not.

Intuitively, primitive people chose sweet fruits, because they have a lot of sugar, which means a lot of calories. Calories are fuel for the body. Salty foods are loaded with minerals, while foods that are bitter and sour are generally considered spoiled or poisonous.

And also taste brings joy .

Did you know that even a cow chooses juicier grass for itself.

I wonder why enjoy food?

Did you know that the best connoisseurs of delicious food are …. cockroaches. They even from a great distance, with the help of saliva, transmit information that there is food. By the way, cockroaches love fruit juice.

Taste is one of the types of human sensations, with the help of which he cognizes the world around him. So why do we strive to eat especially tasty?

It turns out that at first a person begins to take food because of hunger. Hunger is the reaction of the body, forcing us to look for "fuel" in order to survive.

The smart brain then starts producing dopamine, the chemical responsible for pleasure, while eating. As long as food enters the body, we experience pleasure, bliss. After that, we will always associate food with pleasure. Thus, the brain has secured our body, and from time to time we are looking for "something to eat."

The organ of taste is language.

As soon as the food touches the tongue, taste buds capture information and through nerve impulses information enters the cerebral cortex, where, as if in a laboratory, taste recognition occurs.

Look at the picture... What do you see?...

Yes, lemon. What are your feelings? It turns out tastes are stored in memory!

By the way, earlier people They thought that the snake's tongue was a poisonous sting.

In fact, reptiles use their tongue for the same purposes as we do - they taste everything. The snake touches an object and takes a sample from everything that seems curious to it.

Different parts of the tongue are responsible for different taste sensations. The tongue recognizes four basic flavors: sweet, salty, bitter, and sour.

The tip of the tongue recognizes sweet, the root of the tongue is bitter, the lateral part is sour, the area between the tip and the lateral part is salty.

Experiment #2

Try wiping the tip of your tongue dry and licking the sugar... What do you feel?... Nothing. Now wet your sugar on your tongue with saliva. What are the feelings?

Only solutes can cause the sensation of taste.

Solids in the mouth dissolve saliva. From the sensitive areas of the tongue, signals enter the brain, to a special center where taste sensations are formed.

Outside, the tongue is covered with countless papillae. They contain the endings of nerves that can feel what is in the mouth. The tongue is one of the guardians of our body. If you inadvertently take something nasty or stale into your mouth, the tongue will immediately report this to the brain, it will send an order to the mouth muscle, and without hesitation, you will spit out what is harmful to the body.

Experiment #3

The organ of touch is the skin

Touch is the recognition of objects by touch. The organ of touch is the skin. There are many nerve endings on it, through which a person perceives hard and soft, cold and warm, smooth and rough, dry and wet. Thanks to the same nerve endings, a person experiences a feeling of pain. Signals from nerve endings are sent to a special think tank where the sensations of touch are formed.

The skin, it turns out, can “tell” a person about what surrounds him. The skin transmits information to what we touch. With our skin we can feel cold or warm, wind or heat, burning or shock.

All irritations of sensitive cells are transmitted along the nerves to the brain. How does the brain not confuse signals from various organs feelings? It turns out that the same signals go through the visual, auditory or olfactory nerves. It matters which area hemispheres the brain they do.

So, we perceive the world at once with all senses. Their signals complement each other. The brain processes these signals and forms a single impression of what surrounds us.