Human senses hearing sight. Features of the sense organs: smell. The sense organs and the brain, the nervous system: how are they interconnected

Human sense organs are given by nature for good adaptation in the world around. Previously, in the primitive world, the sense organs made it possible to avoid mortal danger and helped in the extraction of food. The sense organs are combined into five main systems, thanks to which we can see, smell, touch, hear sounds, and taste the food we eat.

Eyes

The eyes are perhaps the most important among the sense organs. With the help of them we receive about 90% of all incoming information. The rudiments of the organs of vision are formed during the development of the embryo from its brain.

The visual analyzer consists of: eyeballs, optic nerves, subcortical centers and higher visual centers located in occipital lobes. The eyes perceive information, and with the visual cortex we are able to see and evaluate what information the periphery supplies us. The eyes are gorgeous optical instrument, the principle of which is used today in cameras.

Light passing through the cornea is refracted, narrowed and reaches the lens (biconvex lens), where it is refracted again. Further, the light passes through the vitreous body and converges in focus on the retina (it is part of the center extended to the periphery). Visual acuity in humans depends on the ability of the cornea and lens to refract light. In addition, the eyes are able to move to the side, reducing the load on the spine, thanks to three pairs of oculomotor muscles.

Human sense organs: ears

The ears are part of the organ of hearing. The ear consists of three parts: the outer, middle and inner ear. The outer ear is represented by the auricle, which gradually passes into the outer ear canal. Auricle has an interesting shape and consists mainly of cartilage. Only the shell lobe does not have cartilage. The outer ear is necessary in order to determine the source of the sound, its localization.

In the external passage, which narrows as you move inward, there are sulfur glands that produce the so-called earwax. After the external auditory canal, the middle ear begins, the outer wall of which is the tympanic membrane, capable of perceiving sound vibrations. Behind the membrane is the tympanic cavity, the main part of the middle ear. AT tympanic cavity there are small bones - the stirrup hammer and the anvil, combined into a single chain.

Next to the middle ear is inner ear represented by the cochlea (with auditory cells) and the semicircular canals, which are the organs of balance. Sound vibrations are perceived by the membrane, transmitted to the three auditory ossicles, then to the auditory cells. From the auditory cells, irritation goes along auditory nerve to the center.

Smell

A person can perceive smells thanks to the organ of smell. Olfactory cells occupy a small part in the upper nasal passages. The cells are shaped like hairs, thanks to which they are able to capture the subtleties of various odors. The perceived information is sent along the olfactory (olfactory) threads to the bulbs and further to the cortical centers of the brain. A person can temporarily lose his sense of smell with various colds. Prolonged loss of smell should cause alarm, as it occurs in case of damage to the tract itself or the brain.

Human sense organs: taste

Thanks to the organ of taste, a person is able to evaluate the food he eats in this moment. The taste of food is perceived by special papillae located on the tongue, as well as taste buds in the palate, epiglottis and upper esophagus. The organ of taste is closely related to the organ of smell, so it is not surprising when we feel the taste of food worse when we suffer from some kind of colds. On the tongue, there are certain zones responsible for determining a particular taste. For example, the tip of the tongue determines sweet, the middle determines salty, the edges of the tongue are responsible for determining the acidity of the product, and the root is responsible for bitterness.

Touch

Thanks to the sense of touch, a person is able to study the world around him. He always knows what he has touched, smooth or rough, cold or hot. In addition, thanks to countless receptors that perceive any touch, a person can get joy (there is a release of endorphins - hormones of joy). He can perceive any pressure, change in temperature around and pain. But the receptors themselves, located on the surface, can only report temperature, vibration frequency, pressure force.

Information about what we touched or who hit us, etc. reports the highest station - the brain, which constantly analyzes many incoming signals. With excessive impulses, the brain selectively receives more important impulses. For example, first of all, the brain evaluates signals that are dangerous to human life and health. If pain occurs, if you burned your hand, a command is given to immediately pull your hand away from the damaging factor. Thermoreceptors respond to temperature, baroreceptors to pressure, tactile receptors to touch, and there are also proprioceptors that respond to vibration and muscle stretch.

Signs of the disease

A sign of a disease of one or another sense organ is, first of all, the loss of its main function. If the organ of vision is damaged, vision disappears or worsens, if the organ of hearing is damaged, hearing is reduced or absent.

Man is designed for his interaction with the outside world. A person has five of them:

The organ of vision is the eyes;

Organ of hearing - ears;

Sense of smell - nose;

Touch - skin;

Taste is language.

All of them respond to external stimuli.

organs of taste

Man has taste sensations. This happens due to special cells responsible for taste. They are located on the tongue and are combined into taste buds, each of which has from 30 to 80 cells.

These taste buds are located on the tongue as part of the fungiform papillae, which cover the entire surface of the tongue.

There are other papillae on the tongue that recognize various substances. There are several types concentrated there, each of which distinguishes "its" taste.

For example, salty and sweet determine the tip of the tongue, bitter - its base, and sour - side surface.

Olfactory organ

The olfactory cells are located in the upper nasal part. Various microparticles enter the nasal passages on the mucous membranes, due to which they begin to contact with the cells responsible for smell. This is facilitated by special hairs that are in the thickness of the mucus.

pain, tactile and temperature sensitivity

The sense organs of a person of this species are very important, because it allows you to protect yourself from various dangers of the surrounding world.

Special receptors are scattered over the surface of our body. Cold react to cold, to heat - thermal, to pain - painful, to touch - tactile.

Most of the tactile receptors are located in the lips and on the fingertips. In other parts of the body, there are much fewer such receptors.

When you touch something, tactile receptors are irritated. Some of them are more sensitive, others less, but all the information collected is sent to the brain and analyzed.

The human senses include the most important body- vision, thanks to which we receive almost 80% of all information about the outside world. The eye, lacrimal apparatus, etc. are elements of the organ of vision.

The eyeball has several layers:

The sclera, called the cornea;

choroid, passing in front into the iris.

Inside it is divided into chambers filled with jelly-like transparent contents. Cameras surround the lens - a transparent disk for viewing objects that are close and far.

The inner side of the eyeball, which is opposite the iris and cornea, has light-sensitive cells (rods and cones) that convert into an electrical signal that enters the brain through the optic nerve.

lacrimal apparatus designed to protect the cornea from microbes. The lacrimal fluid continuously washes and moisturizes the surface of the cornea, providing it with sterility. This is facilitated by episodic blinking of the eyelashes.

The human sense organs include consisting of three components - the inner, middle and outer ear. The last one is auditory concha and ear canal. The middle ear is separated from it by the eardrum, which is a small space, with a volume of about one cubic centimeter.

The tympanic membrane and inner ear contain three small bones called the hammer, stirrup and anvil, which transmit sound vibrations from eardrum into the inner ear. The sound-perceiving organ is the cochlea, which is located in inner ear.

The snail is a small tube twisted in a spiral in the form of two and a half special coils. It is filled with a viscous liquid. When sound vibrations enter the inner ear, they are transmitted to a fluid that vibrates and acts on sensitive hairs. Information in the form of impulses is sent to the brain, analyzed, and we hear sounds.

For a long time it was believed that the world we know only with the help of the senses: we see with the eyes, hear with the ears, taste with the tongue, smell with the nose, and with the skin - roughness, pressure, temperature. In fact, the sense organs are only the initial link in perception. The optics of our eye focuses the image on the visual receptors of the retina. The ear converts sound vibrations into mechanical vibrations in the fluid of the inner ear, which are amplified by auditory receptors. In any case, the analysis of external events and internal sensations begins with irritation receptors- sensitive nerve endings, or more complex formations that react to the physical or chemical indicators of their environment, and ends in the neurons of the brain.
Analyzers called systems consisting of receptors, pathways and centers in the cortex big brain. Each analyzer has its own modality, that is, a way of obtaining its own information: visual, auditory, gustatory, etc. The excitations arising in the receptors of the organs of vision, hearing, and touch are of the same nature - electrochemical signals in the form flow of nerve impulses. Each of the nerve impulses enters the corresponding zone of the cerebral cortex. Here, in the primary sensitive zones, the analysis of sensations takes place, in the secondary zones - the formation of images received from the sense organs of one modality (only from sight, or only from hearing or touch). Finally, in tertiary zones The cortex reproduces images or situations received from the sense organs of different modalities, for example, from vision and hearing.

The meaning of vision

The uniqueness of vision in comparison with other analyzers lies in the fact that it allows not only to identify an object, but also its place in space, to monitor movement, and determine the brightness of colors. More 95% A person receives information through vision.
Eyes, to be exact. eyeballs, located in eye sockets- paired depressions in the skull. The color of the iris determines the color of the eyes.

The meaning of hearing

Like sight, hearing makes it possible to perceive information at a considerable distance. With the help of hearing, animals detect prey, escape from predators, and communicate. Hearing is also important for a person, since articulate speech is associated with this analyzer. Having lost their hearing in early childhood, people lose the ability to pronounce words. Long-term therapeutic training is required using a special technique so that a person deaf from birth can speak. Longitudinal vibrations of air carrying sound cause mechanical vibrations of the tympanic membrane. By using auditory ossicles it is transmitted to the membrane oval window, and through it - the fluid of the inner ear. These vibrations cause irritation of the receptors of the spiral organ, the resulting excitations enter the auditory zone of the cerebral cortex and here they form into auditory sensations.

Organs of balance

The orientation of the body in space is carried out by the vestibular apparatus. He is in the depths of the pyramid temporal bone, next to the cochlea of the inner ear. vestibular apparatus consists of two pouches and three semicircular canals. The channels are located in three mutually perpendicular directions. This corresponds to three dimensions of space (height, length, width) and allows you to determine the position and movement of the body in space. The vestibular analyzer ends in the cerebral cortex. Its participation in the implementation of conscious movements allows you to control the body in space.

organ of taste

In the mucous membrane of the tongue there are small elevations - taste buds, mushroom-shaped, grooved or leaf-shaped. Each papilla communicates with oral cavity a small hole sometimes. It leads to a small chamber, at the bottom of which are taste buds. The tip of the tongue perceives sweet better, the lateral edges of the tongue - sour. Receptors located on the anterior and lateral edges of the tongue respond to salty, receptors on the back surface of the tongue to bitter. In the definition of taste, in addition to taste sensations, olfactory, temperature, tactile, and sometimes pain receptors are also involved. The synthesis of all these sensations determines the taste of food. Taste zone cerebral cortex is located on inside temporal lobe, next to the olfactory.

Touch

Touch is a complex sense associated with the feeling of objects. It involves tactile sensations. Along with temperature and muscle sensations they can provide information about the size, shape, roughness, density, as well as some other properties of the object that are important for its definition. Skin sensitivity is composed of several analyzers. tactile feeling associated with analyzers that perceive touch and pressure. On the basis of tactile sensations can be developed vibratory feeling, that is, the ability to recognize and evaluate vibration (fluctuations). For healthy people it is of little importance, but for the deaf-blind-mute, the sensation of vibration becomes one of the possible ways hearing replacement.

Smell

Olfactory receptors are found on the mucous membrane of the middle and superior turbinates. These cells are cilia. Each olfactory cell is capable of detecting a substance of a certain composition. When interacting with him, she sends an impulse to the brain. Not all substances are capable of irritating olfactory cells, but only volatile or soluble in water or fats. Some of the smells are pleasant, others are disgusting.

For the first time in history, the sense organs were studied in detail in the writings of Aristotle. In his treatise On the Soul, he wrote that cognitive abilities of a person occur through thinking, imagination and memory. But he considers sensations to be fundamental in the knowledge of the world by a person. With the help of touch, smell, sight, hearing and taste, a person has the opportunity to get complete picture external world, interact and respond correctly to it.

The sensory system is divided into two categories: remote and tactile. The first includes sight, hearing, and smell. To the second - taste, touch.

The elements of this system perceive energy external influence and in physiology are called anatomical formations (instruments) or analyzers. Thanks to them, transformed nerve impulses come to the brain, and complex analytical chains are created there. With the help of smell, touch and other senses, a person has the ability to navigate in a changing external environment, to respond to certain influences and irritations in a certain way.

Analyzers are the skin and specialized sense organs: ears, eyes, tongue and nose.

Their formation and development was facilitated by endlessly changing conditions. environment man as a biological being. Evolutionary processes also influenced: connections with the cerebral cortex joined the automatic subcortical reflex acts.

Structure of analyzers

The system of sense organs received its second name "analyzers" in the works of the outstanding physiologist I.P. Pavlova. In physiology research nervous activity animals, the scientist studied in detail the path of external excitation that passes through them to brain departments. He wrote that the mammalian organism is equipped with a system that includes five analyzers with an identical structure.

The analyzers of the organs of touch, smell, taste, hearing, and vision include perceiving receptors, conductors. They lead to certain brain centers: light, sound, temperature, chemical.

Vision

Thanks to this analyzer, the brain receives and processes about 80% of all information that comes from the outside world. The visual department is able to perceive an external object, to capture the emitted (reflected) light rays.

It's complicated optical system represented by two closely related structures:

Peripheral, receiving visual information. She, in turn, is outer part: protective and supporting shell of the sclera, reflex narrowing and expanding pupil, moisturizing anterior chamber, iris. The peripheral section includes the cornea with the function of light refraction, the conjunctiva for protection and hydration, the eyelid, and the orbit.
Inner part: refractive light rays vitreous body, focusing vision with the lens and the retina, which is responsible for the perception of shape, color.

The light beam passes through the pupil, cornea, lens and rests on retina. It refracts, “flips” the image and transmits a signal along the optic nerve to the visual cortical brain regions. There nerve impulse is recognized, “unfolded” and perceived already in a three-dimensional form.

Only thanks to vision, a person is able to receive a huge amount of information about the world around him.

Reproducing an object is main function visual analyzer. In addition, he recognizes its size, color characteristics and spatial localization.

Interesting Facts:

Only 1/6 of the eyeball is visible from the outside.
Every twelfth man on the planet suffers from color blindness.
If a person looks at the object of his love, his pupil doubles.
The most active muscles human body- eye. There are six of them.
The eye can discern grey colour in 500 shades.
The organs of vision are able to focus on 50 things in one second.
Nearsighted eyeball long, for far-sighted - short.
At optic nerve over a million fibers.

Hearing

The ability to capture and analyze sound vibrations is provided by the balanced auditory system of analyzers. Thanks to it, a person perceives sound external signals, analyzes and adapts in the external environment. The auditory system is represented by several anatomical structures:

Peripheral part: outer, middle, inner ear.
The central part, consisting of nerve fibers. They conduct impulses to the temporal areas in the cerebral cortex, where the volume, pitch of sound oscillations and vibrations are analyzed.

The structure is responsible for the perception, transmission, gravitational signals and their conduction to the receptors. And it also determines the location of the sound source. The equilibrium-auditory analyzer begins to function even in utero: the fetus feels musical, noise vibration, distinguishes the tonality of voices. A born baby already has a certain set of sounds in his memory, to which he is able to respond.

The auditory analyzer captures and distinguishes sound vibrations in the range from 20 Hz to 20 kHz. With age, the upper indicator decreases to 15 kHz. Most best performance hearing in infants and children under 8 years of age.

Interesting Facts:

Hearing problems in 30% of cases are associated with exposure to noise.
Vaccinations for children against rubella, mumps, measles are an excellent prevention of hearing problems in the future.
One in ten people in the world suffer from hearing loss.
Ears and nose are two organs that grow in a person before death.
Hearing begins to fall from one frequently repeated sound.
Loud sounds weaken the immune system, cause heart palpitations and tachycardia.
men hear worse than women, but better determine the distance and direction from which the sound vibration comes.
Ears should not be cleaned, but washed.
Excess sulfur is pushed out during chewing movements.
After a heavy meal, hearing deteriorates for a while.

Smell

This analyzer has an important task - to recognize odors. The nose, its main organ, makes it possible to take the first step - to inhale. Further, the air passes through the receptor cells of the olfactory epithelium. It is “recognized” by neurosensory cells, directing impulses to certain brain centers: the olfactory cortex, the hypothalamus, and the hippocampus.

Only after all this traveled path, a person is able to realize, remember, identify smells. Interestingly, people's ability to respond to odors can differ:

Macrosmatics with a keen sense of smell, especially sensitive to odors. There are very few such people. This ability is more inherent in the animal world.
Microsmatics (with a small number of olfactory receptors). This group includes most of the human species, primates.
Anosmatics are the smallest group completely devoid of this function.

The human olfactory system can distinguish about 10,000 odors. But there are only seven dominant, defining ones:

Aromatic.
Ethereal.
Fragrant.
Musky.
Putrefactive.
Sulfuric.
Burnt.

They give a person the most detailed picture of the surrounding world about the quality of food, pleasant (unpleasant) moments of life, warn of danger, poisons. The sense of smell has a memory: with a smell heard a long time ago, but a newly arisen smell, a person can remember a long-forgotten event that caused him strong emotions.

There are conditions when the receptors stop working. Reasons for this violation:

Respiratory. Changes in the act of breathing, damage to the nasal mucosa, swelling of the septum against the background of viral or bacterial infections, allergies, polypous growths.
Neurosensory (perceptual). Intracerebral disorders: dysfunction in olfactory neuroepithelial or conduction structures. called acute infections, inhalation of volatile toxic compounds.
Sequelae of traumatic brain injury.
Neoplasms.
Neurosurgical operations.
Age after 70 years.
Tobacco smoking, alcohol abuse, substance abuse.
Neurotoxic and psychotropic drugs.

A person can also develop the opposite condition - an acute perception of smells. In medicine, it is called hyperosmia. The reasons:

Hormonal changes in women (pregnancy, premenstrual period, premenopause).
Mental disorders (neurasthenia, schizophrenia).
Migraine.
Neoplasms of the brain.

Interesting Facts:

Smell is rightfully considered an irresistible element. It is difficult to control it. Bright light - close your eyes loud music- plug your ears. Does it smell strong? You won't be able to breathe for long.
From the first week of life, the baby smells the presence of the mother.
A resident of a metropolis eventually ceases to perceive about 70% of odors.
Most cats love the smell of valerian and mint, dogs love the smell of anise, camels are crazy about tobacco smoke, and lions - from perfumery products.
Large Japanese companies use special aromatic compositions to improve employee performance. The working day begins with a spray of an invigorating smell, in the afternoon - anti-stress and tonic, and in the late afternoon - giving energy.
Functions of sight and smell worsen with age first of all.
Each person has their own unique scent.
The nose has a "memory bank" with 50,000 smells.

Taste

The analyzers responsible for this feeling awaken in human body the very first. Even in intrauterine life, the fetus has already developed a sense of touch, smell and taste. He "tastes" the food that enters the mother's body. Taste is a qualitative analysis of substances by special structures - chemoreceptors, which are located in the oral cavity on the tongue, mucosa. They are outer part contact with food, and internal - in the thickness of the tongue - with nerve endings. According to the area of the organ, they are grouped into islands, the so-called receptor-gustatory areas:

At the tip are sweet food analyzers.
The root reacts to bitter.
Lateral areas - on sour.
The edges and tip are salty.

Taste receptors are innervated by the glossopharyngeal, facial and vagus nerve. Sensory system The oral cavity, in addition to gustatory, has several other functions:

Sensitive. This is a reaction to pain, heat, cold.
Protective. Provides impermeability of mucous membranes from viruses, bacteria.
Suction. The gingival sulcus and the floor of the mouth have high permeability. AT small quantities they are able to absorb sodium and potassium ions, amino acids, alcohol-containing solutions, medications, carbohydrates.

Interesting Facts:

The taste bud lives for 10 days.
Spicy food stimulates not taste, but pain receptors.
25% of the inhabitants of the planet have more taste recipes and taste buds. Thanks to this quality, people become real gourmets.
There are not enough receptors for taste analysis. The olfactory zones of the nasal cavity are involved in the process.
There are 16 muscles in the tongue.
The damaged surface of the tongue heals faster than other tissues of the body.
If the product is not dissolved by saliva in the oral cavity, the person will not feel the taste.

Touch

Skin receptors are responsible for this ability. musculoskeletal system, oral mucosa, genitals.

Touch is multifaceted. With it, a person can determine what shape, size, temperature, consistency of an object or object in contact with him. The work of tactile analyzers is based on the stimulation of special structures - mechanical, thermal and pain receptors - which in the central nervous system are converted into sensitivity of one of three types: tactile (touch, pressure), temperature (cold, heat), pain.

Fingers, palms, feet, lips have increased sensitivity.

Located on skin receptors capture and recognize touch, pressure, pain and send signals to the spinal cord and brain. There, the information is processed and analyzed. After that, it is transformed into sensations: pleasant, unpleasant or simply neutral.

Interesting Facts:

Touch is a feeling that comes to a person first and leaves last.
If you regularly gently stroke a premature baby, he will gain weight faster.
After a back massage, excitable, nervous children and adolescents become calmer.
To a person deprived of sight and hearing, information from the outside world comes only through tactile analyzers.

Without thinking, a person takes the system of feelings for granted and for granted. He wastes his resources, works for wear and tear, does not think about his health and is frivolous about what is given to him by nature. The ability to look and hear, touch and feel is a great gift. You should always remember that to have it means to be a truly happy and free person.

Areas of the brain where information from certain sense organs is processed.

Cones that sense color and rods that sense light and dark in the retina.

The answer to this question can be very different. Conservatives, following Aristotle, speak of five senses - hearing, touch, sight, smell and taste. Poets insist on the sixth, which includes either a sense of beauty, or intuition, or something else. These are non-specialists. But physiologists and physicians also do not agree with each other. The most cautious of them now count only three feelings in a person, the most radical - 33.

Indeed, we often use feelings that are not included in the list of Aristotle. Does seeing, hearing, or any of the five senses help you perform a common neurological test where the doctor asks you to close your eyes and touch the tip of your nose with one finger or the other? And which of the five feelings torment you while pitching at sea? What sense allows you to determine if the tea in the glass is too hot?

So how many feelings does a person have? See how to count.

We can say that there are only three senses: chemical (smell and taste), mechanical (hearing and touch) and light (sight). The reaction of the corresponding sense organs is based on different physical and chemical mechanisms. But even these three feelings can be classified in more detail. For example, taste actually includes five senses: sweet, salty, sour, bitter, and umami (the Japanese word for the taste of monosodium glutamate, a condiment that is indispensable in concentrated soups). A few years ago, scientists discovered that there are separate receptors on the tongue for the taste of umami. French physiologists recently found receptors that respond to the taste of fat, and they are not only on the tongue, but also in small intestine(not without reason a good portion of castor bean oil, known colloquially as castor oil, makes its way to our guts). So a person has six senses of taste.

Vision can be considered as one sense - the sensation of light, as two - light and color, or as four - light and primary colors: red, green and blue. Frogs and some other animals have separate receptors in the retina of their eyes that respond to movement in the field of view - another sense (humans, as far as we know, do not have such receptors).

Let's take a rumor. Is it one sense or several hundred, according to the number of hair cells in the inner ear, each of which responds to a different frequency of oscillation? It is also interesting that as a result of aging or certain diseases, a person may lose the perception of certain frequencies, while the rest will be heard as before.

As for the sense of smell, at least 2000 types of receptors are involved in it. Among them there are very specialized ones, for example, reacting to the smell of the sea, to the smell of lilies of the valley. Should these sensations be considered together, as a single sense of smell, or separately?

We are all able to feel the temperature of surrounding objects, the degree of bending of the limbs in the joints (which allows us to eyes closed quite accurately find the tip of the nose with your finger), we feel an imbalance (which, when pitching, leads to seasickness). Feeling an empty or full stomach Bladder. Is it possible to consider as feelings those sensations that do not reach consciousness, since there is simply no need for this? For example, a person has a sensor that senses pH cerebrospinal fluid, but the adjustment of this parameter occurs without the participation of consciousness.

Perhaps the list should also include a sense of time. Although few of us can tell what time it is without a watch with great accuracy, many of us are quite confident in evaluating the elapsed periods of time, and all have internal biorhythms.

Even conservatives agree that in addition to the classic five people have a sense of pain. And the radicals distinguish three pain sensations: skin, bodily (pain in the joints, bones and spine) and visceral (pain in the insides).

Now most scientists recognize the existence of 21 feelings in humans. The upper limit has not yet been set.