Human hearing system: ear structure, functions, pathologies. Structure and functions of the outer, middle and inner ear. Bone transmission of sounds. Binaural hearing

The process of cognition and sound perception of the world is carried out using the senses. We receive most of the information through vision and hearing. How the human ear works has been known for a long time, but it is not yet entirely clear how exactly sounds of different pitch and strength are recognized.

The auditory analyzer works from birth, although the structure of the infant ear is somewhat different. During a sufficiently loud sound, newborns appear without conditioned reflex, which is recognized by an increase in heart rate, increased breathing, and a temporary stop in sucking.

By two months of life, a conditioned reflex is formed. After the third month of life, a person can already recognize sounds that are different in timbre and pitch. By the age of one, the child distinguishes words by rhythmic contour and intonation, and by the age of three is able to distinguish the sounds of speech.

What does a hearing analyzer consist of?

Vertebrates hear using a pair of organs - the ears, the inner part of which is located in the temporal bones of the skull. Two ears are necessary not only to hear better, but also to help determine where the sound is coming from.

There are several explanations for this: the ear that is closer to the source picks up sound more strongly than the other; the near ear transmits information to the brain faster; sound vibrations reach the perceiving organ in different phases. What does the ear consist of and how does it provide sound perception and sound transmission?

Analyzers are called complex mechanisms, with the help of which information is collected and processed. Analyzers consist of three units. The receptor department perceives irritation with the help of nerve endings. Conducted via nerve fibers transmits a sound impulse to the central nervous system.

The central section is located in the cortex, and this is where a specific sensation is formed. The structure of the human ear is complex, and if the function of at least one section is disrupted, the operation of the entire analyzer stops.

Structure of the human ear

The structure of the ear is the same in almost all mammals. The only difference is in the number of curls of the cochlea and the limits of sensitivity. The human ear consists of 3 sections connected in series:

• outer ear;
• middle ear;
• inner ear.

An analogy can be drawn: the outer ear is a receiver that perceives sound, the middle part is an amplifier, and the human inner ear functions as a transmitter. The outer and middle ears are necessary for conducting sound waves to the receptor section of the analyzer, and the human inner ear contains cells that perceive mechanical vibrations.

Outer ear

The structure of the outer ear is represented by two areas:

• auricle (visible outer part);
• auditory canal.

Task auricle catch the sound and determine where it comes from. In animals (cats, dogs), the shell is mobile; such a device in the ear facilitates sound perception. In humans, the muscle that causes the movement of the shell has atrophied.

The shell is a rather fragile formation, since it consists of cartilage. Anatomically, the lobe, the tragus and antitragus, the helix and its legs, and the antihelix are distinguished. The structure of the auricle, namely its folds, helps to detect where the sound is localized, as they distort the wave.

Individually shaped auricle

The external auditory canal is 2.5 cm long and 0.9 cm wide. The canal begins with cartilaginous tissue (which continues from the auricle) and ends. The canal is covered with skin, where the sweat glands have changed and began to secrete earwax.

It is needed to protect against infection and the accumulation of contaminants, such as dust. Normally, sulfur comes out when chewing.

The eardrum separates the external canal and the middle ear. This is a membrane that does not allow air or water to pass into the organ and is sensitive to the slightest air fluctuations. Thus, it is necessary to protect the inside of the ear and transmit sound. In an adult it is oval, and in a child it is round.

The sound wave reaches the eardrum and causes it to shift. For a person to perceive different frequencies, a membrane movement equal in size to the diameter of a hydrogen atom is sufficient.

Middle ear

In the wall of the human middle ear there are two holes, closed by a membrane, that lead into the inner ear. They are called oval and round windows. Oval window vibrates due to the impacts of the auditory ossicle, the round one is necessary for the vibration to be transmitted in a closed space.

The tympanic cavity is only about 1 cm3. This is enough to accommodate the auditory ossicles - the malleus, incus and stirrup. The sound causes the eardrum to move, which causes the hammer to move, which moves the stapes through the incus.

The functions of the middle ear are not limited to the transmission of vibrations from the external to the internal canal during movement auditory ossicles The sound is amplified 20 times due to the contact of the base of the stapes with the membrane of the oval window.

The structure of the middle ear also requires the presence of muscles that will control the auditory ossicles. These muscles are the smallest in the human body, but they are capable of ensuring that the organ adapts to the simultaneous perception of different frequencies of sounds.

From the middle ear there is an outlet into the nasopharynx through the Eustachian tube. It is about 3.5 cm long and 2 mm wide. Its upper part is in the tympanic cavity, the lower part (pharyngeal mouth) is near hard palate. The pipe is necessary to ensure equal pressure on both sides of the membrane, which is necessary for its integrity. The walls of the tube are closed and expand with the movement of the pharyngeal muscles.

With different pressures, ear congestion appears, as if being under water, and yawning occurs reflexively. Swallowing or strong exhalation through the nose with pinched nostrils will help equalize the pressure.

The eardrum may be ruptured due to pressure changes

Anatomy of the middle ear childhood somewhat different. In children, there is a gap in the middle ear through which infection easily penetrates into the brain, causing inflammation of the membranes. With age, this gap closes. In children, the hearing aid is wider and shorter, located horizontally, so they often develop complications of ENT pathologies.

For example, when there is a sore throat, bacteria travel through the auditory tube into the middle ear and cause otitis media. Often the disease becomes chronic.

Inner ear

The structure of the inner ear is extremely complex. This anatomical region is localized in the temporal bone. It consists of two complex structures, called labyrinths: bone and membranous. The second labyrinth is smaller and located inside the first. Between them there is perilymph. Inside the membranous labyrinth there is also a liquid - endolymph.

The labyrinth contains the vestibular apparatus. Therefore, the anatomy of the inner ear not only allows us to perceive sound, but also controls our balance. The cochlea is a spirally twisted canal consisting of 2.7 turns. It is divided into 2 parts by a membrane. This membranous septum contains more than 24 thousand elastic fibers that move from a sound of a certain pitch.

The fibers on the wall of the cochlea are distributed unevenly, which helps to better detect sounds. On the septum is the organ of Corti, which senses sound from string fibers using hair cells. Here mechanical vibrations are transformed into a nerve impulse.

How does sound perception occur?

The sound waves reach the outer concha and are transmitted to the outer ear, where they cause the eardrum to move. These vibrations are amplified by the auditory ossicles and transmitted to the membrane of the middle window. In the inner ear, vibrations provoke the movement of perilymph.

If the vibrations are quite strong, then they reach the endolymph, and it, in turn, provokes irritation of the hair cells (receptors) of the organ of Corti. Sounds of different heights move fluid in different directions, which is detected nerve cells. They convert mechanical vibrations into a nerve impulse, which reaches the temporal lobe of the cortex through the auditory nerve.

A sound wave entering the ear is converted into a nerve impulse

Physiology sound perception difficult to study because sound causes a slight displacement of the membrane, fluid vibrations are very small, and the anatomical region itself is small and located in the capsule of the labyrinth.

The anatomy of the human ear allows it to detect waves from 16 to 20 thousand vibrations per second. This is not much compared to other animals. For example, a cat perceives ultrasound and is able to detect up to 70 thousand vibrations per second. With age, a person's sound perception deteriorates.

Thus, a thirty-five-year-old person can perceive sound no higher than 14 thousand Hz, and those over 60 years old can only perceive up to 1 thousand vibrations per second.

Ear diseases

The pathological process occurring in the ears can be inflammatory, non-inflammatory, traumatic or fungal. Non-inflammatory diseases include otosclerosis, vestibular neuritis, Meniere's disease.

Otosclerosis develops as a result of pathological tissue proliferation, due to which the auditory ossicles lose mobility and deafness occurs. Most often, the disease begins during puberty and by the age of 30 a person has severe symptoms.

Meniere's disease occurs due to the accumulation of fluid in a person's inner ear. Signs of pathology: nausea, vomiting, tinnitus, dizziness, difficulties with coordination. Vestibular neuritis may develop.

This pathology, if it occurs in isolation, does not cause hearing impairment, however, it can provoke nausea, dizziness, vomiting, tremor, headache, convulsions. Most often noted.

Depending on the location of the inflammation, there are:

• otitis externa;
• otitis media;
• internal otitis;
• labyrinthitis.

Occur as a result of the development of infection.

If otitis media is ignored, the auditory nerve is affected, which can lead to irreversible deafness

Hearing decreases as a result of the formation of plugs in the outer ear. Normally, sulfur is excreted on its own, but if its production is increased or its viscosity changes, it can accumulate and block the movement of the eardrum.

Diseases of a traumatic nature include damage to the auricle due to bruises, the presence of foreign bodies in the auditory canal, deformation of the eardrum, burns, acoustic injuries, vibration injuries.

There are many reasons why hearing loss can occur. It may occur as a result of a violation of sound perception or sound transmission. In most cases, medicine can restore hearing. Held drug therapy, physiotherapy, surgical treatment.

Doctors are able to replace the auditory ossicles or eardrum with synthetic ones, and install an electrode in the human inner ear that will transmit vibrations to the brain. But if hair cells are damaged as a result of pathology, then hearing cannot be restored.

The structure of the human ear is complex and the appearance of a negative factor can impair hearing or lead to complete deafness. Therefore, a person must maintain hearing hygiene and prevent the development of infectious diseases.

The ear is a complex organ in humans and animals, through which perception occurs. sound vibrations and transmitting them to the main nerve center of the brain. The ear also performs the function of maintaining balance.

As everyone knows, the human ear is a paired organ located deep in the temporal bone of the skull. The outside of the ear is limited by the auricle. It is the direct receiver and conductor of all sounds.

The human hearing aid can perceive sound vibrations whose frequency exceeds 16 Hertz. The maximum ear sensitivity threshold is 20,000 Hz.

Structure of the human ear

Part hearing aid person includes:

1. External part
2. middle part
3. Interior

In order to understand the functions performed by certain components, it is necessary to know the structure of each of them. Quite complex sound transmission mechanisms allow a person to hear sounds in the form in which they come from the outside.

• Inner ear. It is the most complex component of the hearing aid. The anatomy of the inner ear is quite complex, which is why it is often called the membranous labyrinth. It is also located in the temporal bone, or more precisely, in its petrous part.
  The inner ear is connected to the middle ear through oval and round windows. The membranous labyrinth includes the vestibule, cochlea, and semicircular canals filled with two types of fluid: endolymph and perilymph. Also in the inner ear is the vestibular system, which is responsible for a person’s balance and his ability to accelerate in space. The vibrations that arise in the oval window are transferred to the liquid. With its help, the receptors located in the cochlea are irritated, which leads to the formation of nerve impulses.

The vestibular apparatus contains receptors that are located on the cristae of the canals. They come in two types: cylinder and flask. The hairs are opposite each other. Stereocilia during displacement cause excitation, and kinocilia, on the contrary, contribute to inhibition.

For a more accurate understanding of the topic, we bring to your attention a photo diagram of the structure of the human ear, which shows the complete anatomy of the human ear:

As you can see, the human hearing system is a rather complex system of various formations that perform a number of important, irreplaceable functions. As for the structure of the outer part of the ear, every person may have individual characteristics, which do not harm the main function.

Hearing aid care is an integral part of human hygiene, since functional disorders may result in hearing loss, as well as other diseases associated with the outer, middle or inner ear.

According to scientific research, a person is more difficult to tolerate vision loss than hearing loss, because he loses the ability to communicate with environment, that is, it becomes isolated.

The structure of the ear is quite complex. Thanks to the ears, a person can perceive sound vibrations; through special nerve endings they enter the brain, where they are transformed into sound images. A person is able to perceive sound, the minimum frequency of which is 16 Hertz. The maximum threshold of perception is sound waves with a frequency of no more than 20 thousand Hertz.

The human ear consists of three parts:

• external;
• average;
• internal.

Each of them performs its own function in transmitting sound. Ears also help maintain balance. This is a paired organ that is located deep in the temporal bone. cranium. From the outside we can only see the auricle. It is thanks to her that all the sounds that surround us are perceived.

Human outer ear

This part of the ear consists of the outer ear canal and the auricle. The auricle is a very elastic and elastic cartilage that is covered with skin. The lobe is located at the bottom of the shell and there is absolutely no cartilage tissue, but only fat. It is covered with skin, which is also located on the cartilage.

The main elements of the auricle are the tragus and antitragus, the helix, its stalk and the antihelix. Its main function is to receive various sound vibrations and transmit them further to the middle ear, and then to the inner ear of a person and then to the brain. Through such a complex process, people can hear. Thanks to the special curls of the auricle, sound is perceived in the form in which it was originally produced. Next, the waves enter the inner part of the shell, that is, the external auditory canal.

The external auditory canal is lined with skin covered with a huge number of sebaceous and sulfur glands. They secrete a secret that helps protect the human ear from various mechanical, infectious, thermal and chemical influences.

The auditory canal ends at the eardrum. It is a barrier that separates the other two parts of the human ear. When the auricle picks up sound waves, they begin to hit the eardrum and thereby cause it to vibrate. This is how the signal enters the middle ear.

Anatomy of the middle ear

The middle ear is small in size and consists of a tiny tympanic cavity. Its volume is only one cubic centimeter. Inside the cavity are three important bones. They are called the malleus, stapes and incus. The hammer has a tiny handle, with its help it communicates with the eardrum. Its head connects to the anvil, which is connected to the stapes. The stirrup closes the oval window into the inner ear. With the help of these three bones, the smallest in the entire skeleton, sound signals are transmitted from the eardrum to the cochlea in the inner ear. These elements slightly enhance the sound so that it sounds clearer and richer.

By using eustachian tube The middle ear connects to the nasopharynx. The main function of this pipe is to maintain balance between atmospheric pressure and those that arise in the tympanic cavity. This allows sounds to be transmitted more accurately.

Inner part of the human ear

The structure of the human inner ear is the most complex in the entire hearing system, and this department plays the most important role. It is located in the petrous part of the temporal bone. The bony labyrinth consists of the vestibule, cochlea and semicircular canals. Small cavity irregular shape is the vestibule. Its lateral wall has two windows. One - oval shape, opens into the vestibule, and the second, having round shape, into the spiral canal of the cochlea.

The snail itself, which is a spiral-shaped tube, is 3 cm long and 1 cm wide. Its internal part is filled with liquid. Hair cells are found on the walls of the cochlea hypersensitivity. They may have the form of cylinders or cones.

The inner ear includes the semicircular canals. Often in medical literature You can find another name for them - organs of balance. They are three tubes, bent in the shape of an arc, and begin and end in the uterus. They are located in three planes, their width is 2 mm. The channels have names:

• sagittal;
• frontal;
• horizontal.

The vestibule and canals are part of the vestibular apparatus, which allows us to maintain balance and determine the position of the body in space. Hair cells are immersed in the fluid located in the semicircular canals. With the slightest movement of the body or head, the liquid moves, pressing on the hairs, due to which the endings vestibular nerve impulses are generated that instantly enter the brain.

Clinical anatomy of sound production

The sound energy that enters the inner ear and is limited by the wall of the bony cochlea and the main membrane begins to be converted into impulses. Fibers are characterized by resonant frequencies and lengths. The shortest waves have 20,000 Hz, and the longest ones have 16 Hz. Therefore, each hair cell is tuned to a specific frequency. There is a certain peculiarity in that the cells of the upper part of the cochlea are tuned to low frequencies, and the lower ones are tuned to high frequencies.

Sound vibrations travel instantly. This is facilitated by the structural features of the human ear. The result is hydrostatic pressure. It causes the covering plate of the organ of Corti, located in the spiral canal of the inner ear, to shift, causing the stereocilia filaments, which give the name to hair cells, to begin to deform. They are excited and transmit information using primary sensory neurons. The ionic composition of endolymph and perilymph, special fluids in the organ of Corti, creates a potential difference that reaches 0.15 V. Thanks to this, we can hear even small sound vibrations.

Hair cells have a close connection with nerve endings, which are part of auditory nerve. Thanks to this, sound waves are converted into electrical impulses and then transmitted to the temporal zone of the cerebral cortex. The auditory nerve contains thousands of thin nerve fibers. Each of them departs from a certain part of the cochlea of ​​the inner ear and thereby transmits a certain sound frequency. Each of the 10,000 fibers of the auditory nerve tries to transmit to the central nervous system its impulse, and they all merge into one powerful signal.

The main function of the inner ear is to convert mechanical vibrations into electrical ones. The brain can only perceive them. With the help of our hearing aid we perceive various types of sound information.

The brain processes and analyzes all these vibrations. It is in it that our sound ideas and images are created. Playing music or a remembered voice can only be displayed because our brain has specific centers that allow us to analyze the information received. Damage to the ear canal, eardrum, cochlea, or any other part of the hearing organ can result in loss of the ability to hear sounds. Therefore, even with minor changes in the perception of sound signals, you need to contact an ENT specialist to determine possible pathology. Only he will give qualified advice and prescribe correct treatment.

Causes of sound perception disorders

The anatomy of the human ear determines its functions. It is the organ of hearing and balance. Hearing is formed in humans at birth. A child who becomes deaf in childhood loses the ability to speak. People suffering from deafness and hard of hearing, although they can perceive external sound information by the movement of the interlocutor’s lips, do not capture the emotions conveyed by words. Lack of hearing negatively affects the vestibular system; it becomes more difficult for a person to navigate in space, since he is not able to perceive changes that sound warns about: for example, the approach of a car.

Weakening or complete loss of hearing ability can be caused by the following reasons:

• wax accumulated in the ear canal;
• damage to receptors and disturbances in the functioning of the inner ear, in which problems arise in the transmission of nerve impulses to the cerebral cortex;
• inflammatory processes;
• too much loud sounds and incessant noise;
• non-inflammatory diseases such as otosclerosis ( hereditary pathology), neuritis of the vestibulocochlear nerve, Meniere's disease, etc.;
• fungal diseases hearing organs;
• traumatic injuries;
• foreign bodies in the ear.

Inflammatory processes are often accompanied by severe pain. When they spread to the internal part, the auditory receptors are affected, which can result in deafness.

The human hearing organ is essential for natural human functioning. The ears are responsible for sensitivity sound waves, processing into nerve impulses and sending the converted decibels to the brain. In addition, the ear is responsible for performing the balance function.

Despite the external simplicity of the auricle, the design of the hearing organ is considered incredibly complex. This material shows the structure of the human ear.

Ear organ has a paired structure and is located in the temporal part of the hemisphere cortex big brain. The ear organ is characterized by the constant performance of several tasks.

However, among the main functions is considered reception and processing of sounds of different frequencies.

These are then transmitted to the brain and send signals to the body in the form of electrical signals.

The hearing aid perceives both low-frequency sounds and high-frequency sounds up to 2 tens of kHz.

Man receives frequencies above sixteen Hertz. However, the highest threshold of the human ear does not exceed twenty thousand Hertz.

For human eye Only the outer area is open. In addition, the ear consists from two departments:

• average;
• internal.

Each section of the hearing aid has an individual structure and specific functions. The three sections are connected in an elongated auditory tube, which is directed into the brain. For visualization of this picture Look at the cross-sectional photo of the ear.

Composition of the human ear

An exceptional organ in the structure of the body is the organ of hearing. Despite its apparent simplicity, this area has a complex design. The main function of the organ is the distinction of signals, noise, tones and speech, their transformation and increase or decrease.

The following elements are responsible for maintaining all tasks in the ear:

1. External part. The structure of this region includes the external concha, which passes into the auditory tube.
2. Next is the tympanic region, which separates the outer ear from the middle region.
3. The cavity behind the tympanic region is called the middle ear, which contains the auditory bones and the Eustachian tube.
4. Next is the inner region of the ear, which is considered one of the most intricate and intricate in the structure of the described organ. The main task of this cavity is to maintain balance.

The anatomy of the ear contains the following structural elements:

• curl;
• – this is a bulge on the outer part of the ear, located on the outer part;
• the paired organ of the tragus is the antihelix. It is located on the top of the lobe;
• earlobe.

Outdoor area

Outer part of the ear that a person sees is called the outer region. It consists of soft tissue and a cartilaginous shell.

Unfortunately, due to the soft structure of this area,

It leads to severe pain and prolonged treatment.

Young children and people professionally involved in boxing or oriental martial arts suffer most from broken cartilage and bones of the ear.

In addition, the auricle is susceptible to numerous viral and. Most often this happens in the cold season and with frequent touching of the hearing organ with dirty hands.

Thanks to outdoor area, the person has ability to hear sounds. It is through the outer part auditory organ sound frequencies move into the brain.

It is interesting that, unlike animals, the human hearing organ is immobile and, in addition to the described functions, does not have additional capabilities.

When sound frequencies enter the outer ear, decibels travel through the ear canal into middle part. To protect and maintain the functioning of the middle ear area, it is covered skin folds. This allows you to further protect your ears and handle any sound frequencies.

The human ear can detect sounds at various distances: from one centimeter to twenty or thirty meters, depending on age.

Sulfur plug.

Helps the outer ear to hear the described sound vibrations auditory tube, which at the end of the passage is transformed into bone tissue. In addition, the auditory tube is responsible for the functioning of the sulfur glands.

Sulfur is a yellow mucous substance necessary to protect the hearing organ from infections, bacteria, dust, foreign objects and small insects.

Usually sulfur is excreted from the body on one's own. However, with improper cleaning or lack of hygiene, sulfur plug. Removing the plug yourself is prohibited, as you may push it further down the ear canal.

To eliminate such unpleasant problem consult a specialist. He will rinse the ear with specialized tinctures. In the situation where going to a qualified doctor is impossible, purchase “” or “”. These products will gently remove wax and clean the ear. However, the use of the drugs is allowed when there is a small accumulation of sulfur.

The outer ear passes into middle area . They are separated eardrum. After processing sounds in this area, the sound moves to the middle part. For visualization, see the photo of the external sink below.

Structure of the outer area

You can clearly see the structure of the human outer ear with a description in the diagram below.

The auricle consists of twelve elements of varying complexity buildings:

• curl;
• rook;
• Darwin's tubercle;
• ear cavity;
• antitragus;
• lobe;
• helix leg;
• tragus;
• sink bowl;
• lower leg of the antihelix;
• triangular fossa;
• upper leg of the antihelix.

The outer ear is made up of elastic cartilage. The upper and outer edge of the ear is transformed into a curl. Paired organ the curl is located closer to the passage. It goes around the outer hole and forms two protrusions:

1. Antitragus located posteriorly.
2. Tragus located in front.

Earlobe represents soft cloth , in which there are no bones and cartilage.

Darwin's tubercle has a pathological structure and is considered an anomaly of the body.

Structure of the human middle ear

Middle ear The human ear is located behind the tympanic region and is considered the main structure of the hearing organ. The volume of the middle part is about one cubic centimeter.

The middle region falls on the temporal part of the head, in which the the following elements:

1. Drum area.
2. The auditory tube unites the nasopharynx and the tympanic part.
3. Next is a part of the temporal bone called the mastoid process. It is located behind the outer part of the auditory tube.

Of the presented elements, it is necessary to analyze in more detail the structure of the drum part, since the main functions of processing sound frequencies take place in this area. So the tympanic region is divided into three parts:

1. Adjacent to the eardrum first part - hammer. Its function is to receive sound waves and transmit them to the next area.
2. After the hammer is the anvil. The main function of this area is the initial processing of sounds and direction to the stapes.
3. Directly in front of the inner region of the hearing organ and after the malleus there is a stapes. It processes the received sound and transfers the cleaned signals further.

Main function of the auditory ossicles- This is the conversion of signals, noise, low or high frequencies and transmission from the outer part to the inner ear. In addition, the malleus, incus and stapes are responsible for the following tasks:

• maintaining the tone of the tympanic region and supporting its functioning;
• softening too high sounds;
• increase in low sound waves.

Any trauma or complications afterwards lead to dysfunction stirrups, anvils and hammers. This can cause not only hearing loss, but also loss of sound acuity forever.

It is important to understand that sharp sounds, such as explosions, can cause a reflex contraction and thereby damage the structure of the hearing organ. This will lead to partial or complete loss hearing

Inner ear

The inner ear is considered one of the most complex components of the described organ. Because of complex design, this area is often called membranous labyrinth.

The inner part is located in the stony region of the temporal bone and is connected to the middle ear by windows of different shapes.

The structure of the human inner ear includes the following elements:

• vestibule of the labyrinth;
• snail;
• semicircular canals.

The last element contains liquids of the form two types:

1. Endolymph.
2. Perilymph.

In addition, in the inner ear there is vestibular system. It is responsible for the function of balance in space.

As mentioned above, the labyrinth is located inside the bony skull.

The inner ear is separated from the brain by a space filled with viscous fluid. She is responsible for conducting sounds.

A snail is located in the same area.

Snail looks like a spiral channel, which is divided into two parts. This spiral-shaped channel is responsible for converting sound vibrations.

Conclusion

Having become familiar with what the ear is made of and its structure, it is important to monitor the health of your ears daily. It's important to support immune system and at the slightest sign of illness, consult a specialist.

Otherwise, the main function of the hearing organ may be disrupted and lead to severe complications in the form of loss of sensitivity to sounds and noises forever.

Remember that the hearing organ must perform its functions smoothly. Inflammation of the ears leads to severe consequences, and any disorders seriously affect a person’s life.

The ear consists of three sections: outer, middle and inner. The outer and middle ears conduct sound vibrations to the inner ear and are sound-conducting apparatus. The inner ear forms the organ of hearing and balance.

Outer ear consists of the auricle, external auditory canal and eardrum, which are designed to capture and conduct sound vibrations to the middle ear.

Auricle consists of elastic cartilage covered with skin. Cartilage is missing only in the earlobe. The free edge of the shell is rolled up and is called the helix, and the antihelix is ​​located parallel to it. At the anterior edge of the auricle there is a protrusion - the tragus, and behind it is the antitragus.

External auditory canal is a short S-shaped curved channel 35-36 mm long. Consists of a cartilaginous part (1/3 of the length) and a bone part (the remaining 2/3 of the length). The cartilage part passes into the bone part at an angle. Therefore, when examining the ear canal, it must be straightened.

The external auditory canal is lined with skin and contains sebaceous and sulfur glands that secrete sulfur. The passage ends at the eardrum.

Eardrum - This is a thin translucent oval plate that is located on the border of the outer and middle ear. It stands obliquely in relation to the axis of the external auditory canal. The outside of the eardrum is covered with skin, and the inside is lined with mucous membrane.

Middle ear includes the tympanic cavity and the auditory (Eustachian) tube.

Tympanic cavity located in the thickness of the pyramid of the temporal bone and is a small cuboid-shaped space with a volume of about 1 cm 3.

The inside of the tympanic cavity is lined with mucous membrane and filled with air. It contains 3 auditory ossicles; malleus, incus and stapes, ligaments and muscles. All bones are connected to each other through a joint and covered with a mucous membrane.

The hammer with its handle is fused to the eardrum, and the head is connected to the anvil, which in turn is movably connected to the stapes.

The significance of the auditory ossicles is to transmit sound waves from the eardrum to the inner ear.

The tympanic cavity has 6 walls:

1. Upper the tegmental wall separates the tympanic cavity from the cranial cavity;

2. Lower the jugular wall separates the cavity from the outer base of the skull;

3. Anterior carotid separates the cavity from the carotid canal;

4. Posterior mastoid wall separates the tympanic cavity from mastoid process

5. Lateral wall- this is the eardrum itself

6. Medial wall separates the middle ear from the inner ear. It has 2 holes:

- oval- window of the vestibule, covered with a stirrup.

- round- window of the cochlea, covered by the secondary tympanic membrane.

The tympanic cavity communicates with the nasopharynx through the auditory tube.

Eustachian tube- This is a narrow channel approximately 35 mm long and 2 mm wide. Consists of cartilaginous and bone parts.

The auditory tube is lined ciliated epithelium. It serves to bring air from the pharynx into the tympanic cavity and maintains pressure in the cavity equal to the external one, which is very important for normal operation sound-conducting apparatus. An infection from the nasal cavity to the middle ear can pass through the auditory tube.

Inflammation of the auditory tube is called Eustachitis.

Inner ear located in the thickness of the pyramid of the temporal bone and separated from its tympanic cavity medial wall. It consists of a bony labyrinth and a membranous labyrinth inserted into it.

Bone labyrinth is a system of cavities and consists of 3 sections: the vestibule, cochlea and semicircular canals.

vestibule- This is a cavity of small size and irregular shape, occupying a central position. She communicates with tympanic cavity using oval and round holes. In addition, the vestibule has 5 small openings through which it communicates with the cochlea and semicircular canals.

Snail is a convoluted spiral canal that forms 2.5 turns around the axis of the cochlea and ends blindly. The axis of the cochlea lies horizontally and is called the bony cochlear shaft. A bone spiral plate wraps around the rod.

Semicircular canals- are represented by 3 arcuate tubes lying in three mutually perpendicular planes: sagittal, frontal, horizontal.

Membranous labyrinth - located inside the bone, its shape resembles it, but is smaller in size. The wall of the membranous labyrinth consists of a thin connective tissue plate covered flat epithelium. Between the bony and membranous labyrinth there is a space filled with fluid - perilymph. The membranous labyrinth itself is filled endolymph and is a closed system of cavities and channels.

In the membranous labyrinth there are elliptical and spherical sacs, three semicircular ducts and a cochlear duct.

Elliptical pouch five openings communicate with the semicircular duct, and spherical- with the cochlear duct.

On inner surface spherical and elliptical pouches(uterus) and semicircular ducts there are hair (sensitive) cells covered with a jelly-like substance. These cells perceive vibrations of the endolymph during movements, turns, and tilts of the head. The irritation of these cells is transmitted to the vestibular part of the VIII pair of cranial nerves, and then to the nuclei medulla oblongata and cerebellum, then to the cortical region, i.e. V temporal lobe big brain.

On a surface sensitive cells located a large number of crystalline formations consisting of calcium carbonate (Ca). These formations are called otoliths. They are involved in the excitation of sensory hair cells. When the position of the head changes, the pressure of the otoliths on the receptor cells changes, which causes their excitation. Sensory hair cells (vestibuloreceptors), spherical, elliptical sacs (or utricles) and three semicircular ducts make up vestibular (otolith) apparatus.

Cochlear duct It has triangular shape and is formed by the vestibular and main (basilar) membrane.

On the walls of the cochlear duct, namely on the basilar membrane, there are receptor hair cells (auditory cells with cilia), the vibrations of which are transmitted to the cochlear part of the VIII pair of the cranial nerves, and then along this nerve the impulses reach the auditory center located in the temporal lobe.

In addition to hair cells, on the walls of the cochlear duct there are sensory (receptor) and supporting (support) cells that perceive vibrations of the perilymph. The cells located on the wall of the cochlear duct form the auditory spiral organ (organ of Corti).