What do the auditory ossicles do. Auditory ossicles: Hammer, malleus; Anvil, incus; Stirrup, stapes

Most information about the world around a person receives through sight and hearing. Moreover, the structure of the ear is very complex. Any disturbances in the middle ear or other parts of the hearing aid can lead not only to hearing loss, but also to the creation of a situation when a person’s life is in danger. Let's see what are the functions and structure of the middle ear, what diseases affect this part of the hearing aid and how to prevent their occurrence.

The middle ear is located between the inner and outer. The main purpose of this part of the hearing aid is to conduct sounds. The middle ear consists of the following parts:

1. The auditory ossicles. They are a stirrup, hammer, and anvil. It is these details that help to convey sounds, and distinguish them by strength and height. The features of the auditory ossicles help protect the hearing aid from sharp and loud sounds.
2. Auditory trumpet. This is the stroke connecting the nasopharynx with the tympanic cavity. Its mouth is closed when a person swallows or sucks something. In newly born children, for some time, the auditory tube is wider and shorter than in adulthood.
3. Drum cavity. It is this part of the middle ear that contains the auditory ossicles described above. The location of the tympanum is the area between the outer ear and the temporal bone.
4. Mastoid. This is the convex part of the temporal bone. It contains cavities that are filled with air and communicate with each other through narrow holes.

The middle ear is a device that conducts sound vibrations, consisting of air cavities and complex anatomical formations. The drum cavity is covered with a mucous membrane and is separated from the rest of the skull by the upper wall. All auditory ossicles are also covered with mucous membranes. The middle and inner ear are separated by a bone wall. They are interconnected by only two holes:

• round window;
• oval window in the ear.

Each of them is protected by a flexible and elastic membrane. The stirrup - one of the auditory ossicles - enters the oval window located in front of the inner ear filled with water.

Important! Also, in the work of this part of the hearing aid, a huge role is given to muscles. There is a muscle that affects the eardrum, and a muscle group that controls the auditory ossicles.

Middle ear function

Air cavities and other anatomical formations located in the middle ear provide sound patency. The main functions of the middle ear are:

• maintaining the performance of the eardrum;
• transmission of sound vibrations;
• protection inner ear from sharp and too loud sounds;
• ensuring the susceptibility of sounds of varying strength, height and volume.

Important! The main function of the middle ear is to conduct sounds. And any disease or trauma that affects this part of the hearing aid can lead to irreversible total or partial hearing loss.

Middle ear disease

The main symptoms of the occurrence of problems in the middle ear, experts call the following signs and conditions of a person:

• pain in the ear area of \u200b\u200bvarying intensity (mostly very severe);
• feeling of stuffiness;
• decreased or total hearing loss;
• secretion of fluid or pus from the ear canal;
• fever;
• decreased appetite and decreased sleep;
• changing the color of the eardrum to red.

Among the most common diseases of the middle ear, it is worth noting the following:

1. Purulent otitis media of the middle ear. This inflammation, in which purulent and purulent-bloody discharge from the ear canal is observed, a person complains of intolerable pain, hearing is significantly impaired. The disease affects the middle ear cavity and eardrum, and can spread to other parts of the hearing aid.
2. Cicatricial otitis media. In this case, the inflammatory process has led to scarring and reduced mobility of the auditory ossicles. Because of this, severe hearing impairment is observed.
3. Mesotympanite. The disease is similar in symptoms with purulent otitis media. In this case, the eardrum is affected, and a person notes hearing loss and purulent discharge.
4. Epitempanitis. In the course of this disease, inflammation of the middle ear’s drum space occurs, a prolonged course of the inflammatory process may disrupt the structure of the middle and inner ear, which will lead to a decrease and a sharp deterioration in hearing.
5. Mastoiditis. Most often this is a consequence of purulent otitis media that is not correctly and timely treated, which affects not only the middle ear, but also the mastoid process.
6. Qatar middle ear. The disease usually precedes purulent otitis media and affects the auditory tube.
7. Bullous otitis media. The disease occurs against the background of the flu and has symptoms similar to other otitis media. The focus of the inflammatory process is located in the drummed air cavity.

Important! Often, problems with the middle ear can occur against a background of various diseases of an infectious nature, for example, tonsillitis, sinusitis, rhinitis, laryngitis, flu. Also common causes are improper ear and nose care, injuries, water entering the ear canal, hypothermia and drafts.

Middle Ear Disease Prevention

Wear a hat in the winter season

As a prevention of the development of middle ear diseases, experts recommend that children and adults adhere to the following rules:

1. Timely treat diseases of the upper respiratory tract, nose and ears. Infection with improperly selected treatment or its absence quickly spreads further from the nasopharynx or outer ear, which disrupts the functioning of the hearing aid. Always follow the recommendations of doctors during the treatment of diseases of ENT organs. Do not stop the therapy, even if you feel great, do not change the dosage and treatment regimen of the drugs, do not extend the period of their use.
2. If a person has congenital anomalies in the structure of the ear, then they should be resolved with the help of a specialist, if possible. Sometimes it is necessary to perform an operation, and in some cases, taking certain medications is enough.
3. Hygiene. Accumulation of sulfur, dirt or water entering the ear canal can lead to inflammation. Therefore, try to clean your ears with cotton swabs in a timely manner. During swimming or bathing, use special caps and ear plugs, avoid getting a direct stream of water in the ear canal.
4. Ensure that your ears are not injured. Foreign bodies, the use of sharp and hard objects when cleaning the ears, as well as some other causes, can cause inflammation and cause infection in the middle ear.
5. Wear a hat in the winter. Protect yourself from drafts and hypothermia, sudden changes in temperature and humidity. It is best for small children to wear special thin caps, even if the room is at a comfortable temperature.
6. In childhood, as a prophylaxis of frequently occurring otitis media and other inflammatory processes due to overgrown or greatly enlarged adenoids, their removal is sometimes recommended.

Important! The best prevention of middle ear diseases is to strengthen immunity. A balanced diet, moderate physical activity, hardening - all this will increase the stamina and resistance of the body to infections and at times reduce the risk of developing diseases.

Remember, middle ear diseases are very dangerous for a person’s hearing and life. For any disturbing symptoms, you should immediately consult a doctor. Self-medicate for otitis media and others inflammatory processes not in childhood or adulthood. This can lead to serious complications, including the spread of infection beyond the middle ear, its penetration into the brain, as well as a decrease in and total loss of hearing. The sooner you go to the doctor and start treatment, the lower the risk of complications and the higher the chance of eliminating the disease in the shortest possible time without any consequences.

The auditory sensory system of a person perceives and distinguishes a huge range of sounds. Their diversity and wealth serves us as a source of information about current events of the surrounding reality, and as an important factor affecting the emotional and mental condition of our body. In this article, we will consider the anatomy of the human ear, as well as the features of the functioning of the peripheral part of the auditory analyzer.

The mechanism for distinguishing sound vibrations

Scientists have found that the perception of sound, which, in essence, is the vibration of the air in the auditory analyzer, is transformed into a process of excitation. The peripheral part containing receptors and part of the ear is responsible for the sensation of sound stimuli in the auditory analyzer. She perceives the amplitude of oscillations, called sound pressure, in the range from 16 Hz to 20 kHz. In our body, the auditory analyzer also plays such a crucial role as participation in the work of the system responsible for the development of articulate speech and the entire psycho-emotional sphere. First, get acquainted with the general plan of the structure of the organ of hearing.

Departments of the peripheral part of the auditory analyzer

The anatomy of the ear distinguishes three structures called the outer, middle and inner ear. Each of them performs specific functions, not only interconnected, but also all together carrying out the processes of receiving sound signals, their conversion into nerve impulses. According to the auditory nerves, they are transmitted to the temporal lobe of the cerebral cortex, where the sound waves are transformed into the form of various sounds: music, birdsong, the sound of the sea surf. In the process of phylogenesis of the biological species “Homo sapiens”, the hearing organ played a crucial role, as it ensured the manifestation of such a phenomenon as human speech. Departments of the organ of hearing were formed during the embryonic development of a person from the external germ layer - the ectoderm.

Outer ear

This part of the peripheral section picks up and directs air vibrations to the eardrum. The anatomy of the outer ear is represented by the cartilaginous concha and the external auditory canal. What does it look like? The external shape of the auricle has characteristic bends - curls, and is very different in different people. On one of them there may be a Darwin hillock. It is considered a rudimentary organ, and is homologous in origin to the pointed upper edge of the ear of mammals, especially primates. The lower part is called the lobe and is a connective tissue covered with skin.

The auditory meatus is the structure of the outer ear

Further. The auditory meatus is a tube made up of cartilage and partly bone. It is covered with an epithelium containing modified sweat glands that secrete sulfur, which moisturizes and disinfects the passage cavity. The auricle muscles in most people are atrophied, unlike mammals, whose ears actively respond to external sound stimuli. Pathology disorders of the anatomy of the structure of the ear are recorded in early period development of branchial arches of the human embryo and may take the form of cleavage of the lobe, narrowing of the external auditory meatus or agenesis - the complete absence of the auricle.

Middle ear cavity

The auditory meatus ends with an elastic film separating the outer ear from its middle part. This is the eardrum. She receives sound waves and begins to oscillate, which causes similar movements of the auditory ossicles - a malleus, anvil and stapes, located in the middle ear, in the depth of the temporal bone. The hammer with its handle is attached to the eardrum, and the head is connected to the anvil. She, in turn, closes with a long end with a stepladder, and it attaches to the window of the vestibule, behind which is the inner ear. Everything is very simple. Anatomy of the ears revealed that a muscle is attached to the long process of the malleus, which reduces the tension of the eardrum. And the so-called "antagonist" is attached to the short part of this auditory ossicle. Special muscle.

Eustachian tube

The middle ear is connected to the pharynx through a canal named after the scientist who described its structure, Bartolomeo Eustahio. The tube serves as a device that evens out the pressure of the atmospheric air on the eardrum from two sides: from the external auditory canal and the middle ear cavity. This is necessary so that the vibrations of the eardrum without distortion are transmitted to the fluid of the membranous labyrinth of the inner ear. The Eustachian tube is heterogeneous in its histological structure. Anatomy of the ears revealed that it contains not only the bone part. Also cartilage. Sinking down from the middle ear cavity, the tube ends with a pharyngeal opening located on the lateral surface of the nasopharynx. During swallowing, muscle fibrils attached to the cartilage of the tube contract, its lumen expands, and a portion of the air enters the tympanic cavity. The pressure on the membrane at this moment becomes the same on both sides. Around the pharyngeal opening is a section of lymphoid tissue that forms nodes. It is called Gerlach's amygdala and is part of the immune system.

Features of the anatomy of the inner ear

This part of the peripheral part of the auditory sensory system is located deep in the temporal bone. It consists of semicircular canals related to the organ of equilibrium and the bone labyrinth. The latter structure contains a cochlea, inside which is located the organ of Corti, which is a sound-sensing system. Along the spiral, the cochlea is divided by a thin vestibular plate and a denser main membrane. Both membranes divide the cochlea into canals: lower, middle and upper. At its wide base, the upper channel begins with an oval window, and the lower is closed by a round window. Both of them are filled with liquid contents - perilymph. It is considered a modified cerebrospinal fluid - a substance that fills the spinal canal. Endolymph is another fluid that fills the channels of the cochlea and accumulates in the cavity where the nerve endings of the equilibrium organ are located. We will continue to study the anatomy of the ears and consider those parts of the auditory analyzer that are responsible for transcoding sound vibrations into the excitation process.

The meaning of the organ of Corti

Inside the cochlea there is a membranous wall called the main membrane, on which there is a cluster of cells of two types. Some perform the function of support, others are sensory - hairy. They perceive the oscillations of the perilymph, convert them into nerve impulses and transmit further to the sensitive fibers of the vestibular cochlear (auditory) nerve. Further, the excitation reaches the cortical center of hearing located in the temporal lobe of the brain. It distinguishes sound signals. Clinical anatomy ear confirms the fact that to determine the direction of sound, what we hear with two ears is important. If sound vibrations reach them at the same time, a person perceives sound in front and behind. And if the waves come in one ear earlier than the other, then perception occurs on the right or left.

Theories of Sound Perception

At present, there is no consensus on exactly how the system functions, which analyzes sound vibrations and translates them into the form of sound images. The anatomy of the structure of the human ear highlights the following scientific ideas. For example, the Helmholtz resonance theory states that the cochlear’s main membrane functions as a resonator and is capable of decomposing complex vibrations into simpler components, since its width is not the same at the top and bottom. Therefore, when sounds appear, resonance occurs, as in a string instrument - a harp or piano.

Another theory explains the process of the appearance of sounds by the fact that a traveling wave appears in the fluid of the cochlea as a response to the oscillations of the endolymph. Vibrating fibers of the main membrane resonate with a specific frequency of vibration; nerve impulses appear in the hair cells. They enter the auditory nerves into the temporal part of the cerebral cortex, where the final analysis of sounds takes place. Everything is extremely simple. Both of these theories sound perception based on knowledge of the anatomy of the human ear.

Everyone knows that the human ear has a complex structure: the outer, middle and inner ear. The middle ear plays an important role in the entire auditory process, as it performs a sound-conducting function. Diseases that occur in the middle ear are a direct threat to human life. Therefore, to study the structure, functions and methods of protecting the middle ear from infections is a very urgent task.

Organ structure

The middle ear is deep in the temporal bone and is represented by the following organs:

• tympanic cavity;

The middle ear is arranged as a collection of air cavities. Its central part is the tympanic cavity - the area between and. It has a mucous surface and resembles a prism or tambourine. The drum cavity is separated from the skull by the upper wall.

Anatomy of the middle ear involves the separation of its bone wall with the inner ear. There are 2 holes in this wall: round and oval. Each hole, or window, is protected by an elastic membrane.

The middle ear cavity contains and that transmit sound vibrations. Such bones include: a malleus, an anvil and stirrup. The names of the bones arose in connection with the features of their structure. The mechanism of interaction of the auditory ossicles resembles a leverage system. The malleus, anvil and stirrup are connected by joints and ligaments. In the center of the eardrum is the handle of the malleus, its head is connected to the anvil, and it is connected by a long process to the head of the stapes. The stirrup enters the oval opening, behind which there is a vestibule - a part of the inner ear filled with fluid. All bones are covered with mucous membrane.

An important element of the middle ear is the auditory tube. It connects the tympanic cavity with the external environment. The mouth of the pipe is located at hard palate and opens into the nasopharynx. The mouth of the auditory tube is closed when there are no sucking or swallowing movements. There is one feature of the structure of the pipe in newborns: it is wider and shorter than in an adult. This fact facilitates the penetration of viruses.

The mastoid process is the process of the temporal bone, which is located behind it. The structure of the process is cavity, since it contains cavities filled with air. The cavities communicate with each other through narrow slits, which allows the middle ear to improve its acoustic properties.

The structure of the middle ear suggests the presence of muscles. The muscle straining the eardrum and the stirrup are the smallest muscles in the entire body. With their help, the auditory ossicles are supported on weight, regulated. In addition, the muscles of the middle ear provide accommodation for different sounds in height and strength.

Purpose and functions

The functioning of the organ of hearing without this element is impossible. The middle ear contains the most important components, which together perform the function of sound conduction. Without a middle ear, this function could not be realized, and a person could not hear.

The auditory ossicles provide bone conduction of sound and mechanical transmission of vibrations to the oval window of the vestibule. 2 small muscles perform a number of important hearing tasks:

• maintain the tone of the eardrum and the mechanism of the auditory ossicles;
• protect the inner ear from strong sound irritations;
• provide accommodation of the sound-conducting apparatus to sounds of different strength and height.

Based on the functions that the middle ear with all its components performs, we can conclude that without it, the auditory function would be unfamiliar to a person.

Middle ear disease

Ear diseases are one of the most unpleasant ailments for humans. They carry a great danger not only to health, but also to human life. The middle ear, as the most important part of the auditory organ, is prone to various diseases. Leaving the middle ear disease untreated, a person runs the risk of becoming deaf and significantly reducing the quality of his life.

He ends eardrumblindly closes the auditory meatus, borders:

• with the joint of the lower jaw, when chewing, the movement is transmitted to the cartilaginous part of the passage;
• with cells of the mastoid process, facial nerve;
• with salivary gland.

The membrane between the outer ear and the middle is an oval translucent fibrous plate, 10 mm in length, 8-9 mm in width, 0.1 mm in thickness. The membrane area is about 60 mm 2.

The plane of the membrane is inclined to the axis of the ear canal at an angle, pulled funnel-shaped into the cavity. The maximum tension of the membrane in the center. Behind the eardrum is the middle ear cavity.

Distinguish:

• middle ear cavity (tympanic);
• auditory tube (Eustachian);
• auditory ossicles.

Drum cavity

The cavity is located in the temporal bone, its volume is 1 cm 3. It contains auditory ossicles articulated with the eardrum.

A mastoid process, consisting of air-bearing cells, is placed above the cavity. It houses a cave - an airborne cell serving in the anatomy of the human ear as the most characteristic reference point for any operations on the ear.

Auditory trumpet

The formation is 3.5 cm long, with a lumen diameter of up to 2 mm. Its upper mouth is located in the tympanic cavity, the lower pharyngeal mouth opens in the nasopharynx at the level of the hard palate.

The auditory tube consists of two departments, separated by its narrowest place - the isthmus. The bone part departs from the tympanic cavity, below the isthmus - membranous-cartilaginous.

The walls of the tube in the cartilaginous department in the normal state are closed, open slightly when chewing, swallowing, yawning. The expansion of the lumen of the tube is provided by two muscles associated with the palatine curtain. The mucous membrane is lined with epithelium, the cilia of which move to the pharyngeal orifice, providing drainage function pipes.

The smallest bones in human anatomy - the auditory ossicles of the ear, are designed to conduct sound vibrations. In the middle ear there is a chain: hammer, stirrup, anvil.

The hammer is attached to the drum membrane, its head is articulated with a hard place. The anvil process is connected to a stapes attached with its base to the vestibule window located on the labyrinth wall between the middle and inner ear.

The structure is a labyrinth consisting of a bone capsule and a membranous formation that repeats the shape of the capsule.

In the bone maze are distinguished:

• vestibule;
• a snail;
• 3 semicircular canals.

Snail

Bone formation is a 2.5-volume volute spiral around a bone shaft. The width of the base of the cochlear cone is 9 mm, the height is 5 mm, and the length of the bone helix is \u200b\u200b32 mm. A spiral plate departs from the bone rod into the labyrinth, which divides the bone labyrinth into two channels.

At the base of the spiral plate are the auditory neurons of the spiral ganglion. In the bone labyrinth is the perilymph and the membranous labyrinth filled with endolymph. The membranous labyrinth is suspended in the bone with the help of cords.

Perilymph and endolymph are functionally related.

• Perilymph - in ionic composition is close to blood plasma;
• endolymph - similar to intracellular fluid.

Violation of this balance leads to an increase in pressure in the maze.

The cochlea is an organ in which the physical vibrations of the perilymph fluid are converted into electrical impulses of the nerve endings of the cranial centers, transmitted to the auditory nerve and the brain. In the upper part of the cochlea there is an auditory analyzer - a Corti organ.

Vestibule

The oldest anatomically middle part of the inner ear is the cavity bordering the cochlear staircase by means of a spherical sac and semicircular canals. On the wall of the vestibule leading into the tympanum, there are two windows - oval, covered with a stepladder and round, which is a secondary eardrum.

Features of the structure of semicircular canals

All three mutually perpendicular bony semicircular canals have a similar structure: they consist of an expanded and simple leg. Inside the bony are membranous canals, repeating their shape. Semicircular canals and vestibules make up the vestibular apparatus, are responsible for balance, coordination, and determining the position of the body in space.

The organ is not formed in the newborn; it differs from the adult in a number of structural features.

Auricle

• The sink is soft;
• the lobe and curl are weakly expressed, form by 4 years.

Auditory passage

• The bone part is not developed;
• the walls of the passage are almost flush;
• the drum membrane lies almost horizontally.

• The sizes are almost as in adults;
• in children the eardrum is thicker than in adults;
• covered with mucous membrane.

Drum cavity

In the upper part of the cavity there is an open gap through which, in acute otitis media, the infection can penetrate the brain, causing meningism. In an adult, this gap heals.

The mastoid process in children is not developed, it is a cavity (atrium). The development of the process begins at the age of 2 years, ends by 6 years.

Auditory trumpet

In children, the auditory tube is wider, shorter than in adults, located horizontally.

A complexly arranged paired organ receives sound vibrations of 16 Hz - 20,000 Hz. Injuries, infectious diseases reduce the threshold of sensitivity, lead to gradual hearing loss. Advances in medicine in the treatment of diseases of the ears, hearing aid can restore hearing in the most difficult cases of hearing loss.

Video about the structure of the auditory analyzer

The middle ear (auris media) consists of several communicating airways: the tympanic cavity (cavum tympani), the auditory tube (tuba auditiva), the cave entrance (aditus ad antrum), the cave (antrum) and the associated mastoid airways (cellulae mastoidea). Through the auditory tube, the middle ear communicates with the nasopharynx; under normal conditions, this is the only communication of all cavities of the middle ear with the external environment.

1 - horizontal semicircular canal; 2 - channel of the facial nerve; 3 - the roof of the tympanum; 4 - vestibule window; 5 - half-channel muscle; 6 - tympanal opening of the auditory tube; 7 - channel of the carotid artery; 8 - promontorium; 9 - a drum nerve; 10 - jugular fossa; 11 - a window of a snail; 12 - a drum string; 13 - a pyramidal process; 14 - entrance to the cave.

B a r b a n n a l a nce (Fig. 4.4). The drum cavity can be compared with an irregularly shaped cube with a volume of up to 1 cm3. Six walls are distinguished in it: upper, lower, front, back, outer and inner.

The upper wall, or roof, of the tympanic cavity (tegmen tympani) is represented by a bone plate 1-6 mm thick. It separates the tympanic cavity from the middle cranial fossa. There are small openings in the roof through which vessels carrying blood from solid meninges to the mucous membrane of the middle ear. Sometimes in top wall degenerations are formed; in these cases, the mucous membrane of the tympanic cavity is directly adjacent to the dura mater.

In newborns and children of the first years of life, on the border between the pyramid and the scales of the temporal bone there is an unpainted gap (fissura petrosquamosa), which causes their brain symptoms in acute inflammation of the middle ear. Subsequently, a suture (sutura petrosquamosa) is formed at this place and communication with the cranial cavity at this place is eliminated.

The bottom (bottom) of the wall, or the bottom of the tympanic cavity (paries jugularis), borders the underlying jugular fossa (fossa jugularis), which houses the jugular vein bulb (bulbus) venae jugularis). The more the hole protrudes into the tympanic cavity, the thinner the bone wall. The lower wall can be very thin or have a degeneration through which the vein bulb sometimes protrudes into the tympanic cavity. This makes it possible to injure the jugular vein bulb, accompanied by severe bleeding, with paracentesis or careless curettage of granulations from the bottom of the tympanic cavity.

Anterior, tubular or carotid (paries tubaria, s.caroticus), the tympanic cavity is formed by a thin bone plate, outside of which the internal carotid artery is located. There are two holes in the front wall, the upper of which, narrow, leads to the half-channel for the muscle that stretches the eardrum (semicanalis m.tensoris tympani), and the lower, wide, to the tympanic mouth of the auditory tube (ostium tympanicum tybae auditivae). In addition, the front wall is penetrated by thin tubules (canaliculi caroticotympanici), through which blood vessels and nerves pass into the tympanic cavity, in some cases it has degenerations.

The posterior (posterior) site of the tympanic cavity (paries mastoideus) is bordered by the mastoid process. In the upper part of this wall there is a wide passage (aditus adantrum), which communicates the drum recess - attic (attic) with a constant cell of the mastoid process - a cave (antrum mastoideum). Below this passage is a bone protrusion - the pyramidal process, from which the stapedius muscle (m.stapedius) begins. On the outer surface of the pyramidal process there is a tympanic opening (apertura tympanica canaliculi chordae) through which a tympanic string (chorda tympani) enters the tympanic cavity, extending from the facial nerve. In the thickness of the lower part of the posterior wall, the descending knee of the canal of the facial nerve passes.

The external (transverse) wall of the tympanic cavity (paries membranaceus) is formed by the tympanic membrane and partly in the attic by a bone plate that extends from the upper bone walls of the external auditory meatus.

INTERNAL I (LABORATION, MEDIUM, PROMONTORAl I ) with a wall of the tympanic cavity (paries labyrinthicus) is the outer wall of the labyrinth and separates it from the cavity of the middle ear. In the middle part of this wall there is an oval-shaped elevation - a cape (promontorium), formed by the protrusion of the main snail curl.

To the rear and top of the cape there is a niche of the vestibule window (oval window according to the old nomenclature; fenestra vestibuli), closed by the stapes base (basis stapedis). The latter is attached to the edges of the window through an annular ligament (lig. Annulare). In the direction back and down from the cape there is another niche, at the bottom of which there is a snail window (a round window according to the old nomenclature; fenestra cochleae) leading to the snail and closed by a secondary eardrum (membrana ympany secundaria), which consists of three layers: the outer - mucous, middle - connective tissue and internal - endothelial.

How is sound perception

Sound waves reach the outer shell and are transmitted to the outer ear, where the eardrum is forced to move. These vibrations are amplified by the auditory ossicles and transmitted to the middle window membrane. In the inner ear, vibrations provoke the movement of the 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 Corti's organ. Sounds of various heights move fluid in different directions, which is captured by nerve cells. They turn mechanical vibration into a nerve impulse that reaches the temporal lobe of the cortex through the auditory nerve.

Sound wave penetrating the ear is converted into a nerve impulse

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

The anatomy of the human ear allows you to capture waves from 16 to 20 thousand fluctuations per second. This is not much compared to other animals. For example, a cat perceives ultrasound and is able to catch up to 70 thousand vibrations per second. With age, sound perception in a person worsens.

So, a thirty-five-year-old person can perceive sound no higher than 14 thousand Hz, and over 60 he catches only up to 1 thousand oscillations per second.

Ear diseases

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

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

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

This pathology, if it proceeds in isolation, does not cause hearing impairment, however, it can provoke nausea, dizziness, vomiting, tremor, headache, and convulsions. Ear infections of an inflammatory nature are most often noted.

Depending on the location of inflammation, there are:

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

They arise 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 is reduced as a result of the formation of plugs in the outer ear. Normally, sulfur is excreted independently, but, in the case of its increased production or change in viscosity, it can accumulate and block the movement of the eardrum.

Traumatic diseases include damage to the auricle due to bruises, the presence of foreign bodies in the auditory canal, deformation of the tympanic membrane, burns, acoustic injuries, vibration injuries.

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

Doctors are able to replace the auditory ossicles or eardrum with synthetic ones, install an electrode in the inner ear of a person that will transmit vibrations to the brain. But if hair cells suffer as a result of pathology, then hearing is impossible to restore.

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 comply with hearing hygiene and prevent the development of infectious diseases.

Table of contents of the subject "Anatomy of the Ear":
1. The vestibule-cochlear organ, organum vestibulocochleare. The structure of the organ of equilibrium (pre-cochlear organ).
2. Embryogenesis of the organ of hearing and gravity (equilibrium) in humans.
3. The outer ear, auris externa. Auricle, auricula. External auditory meatus, meatus asusticus externus.
4. Eardrum, membrana tympani. Vessels and nerves of the outer ear. Blood supply to the outer ear.
5. Middle ear, auris media. Drum cavity, cavitas tympanica. The walls of the tympanum.
6.
7. Muscle straining the eardrum, m. tensor tympani. The muscle muscle, m. stapedius. The function of the muscles of the middle ear.
8. The auditory tube, or Eustachian tube, tuba auditiva. Vessels and nerves of the middle ear. Blood supply to the middle ear.
9. Inner ear, labyrinth. Bony Labyrinth, labyrinthus osseus. Vestibulum.
10. Bony semicircular canals, canales semicirculares ossei. Snail, cochlea.
11. The membranous labyrinth, labyrinthus membranaceus.
12. The structure of the auditory analyzer. Spiral organ, organon spirale. Helmholtz theory.
13. Vessels of the inner ear (labyrinth). Blood supply to the inner ear (labyrinth).

Auditory ossicles: Hammer, malleus; Anvil, incus; Stirrup, stapes. The function of the bones.

Located in tympanic cavity three small auditory ossicles in appearance are the names of the malleus, anvil and stapes.

1. Gavel, malleusequipped with a rounded caput malleiwhich through necks, collum malleiconnects to handle, manubrium mallei.

2. Anvil, incushas a body, corpus incudis, and two diverging processes, of which one is more short crus brevedirected back and rests in a hole, and the other - long process, crus longumgoes parallel to the handle of the malleus medially and posterior to it and at its end has a small oval thickening, processus lenticularisarticulating with stirrup.

3. Stirrup, stapes, in its form justifies its name and consists of small heads, caput stapedisbearing articulated surface for processus lenticularis anvil and two legs: front, more straight, crus anterius, and back, more curved, crus posteriusthat connect with oval plate, basis stapedisinserted into the vestibule window.
In the joints of the auditory ossicles between themselves are formed two real joints with limited mobility: articulatio incudomallearis and articulatio incudostapedia. Stirrup plate connects to edges fenestra vestibuli through connective tissue, syndesmosis tympano-stapedia.

Hearing bones reinforced, in addition, by several more separate ligaments. Generally all three auditory ossicles represent a more or less movable chain running across the tympanic cavity from the tympanic membrane to the labyrinth. Bone motility gradually decreases in the direction from the malleus to the stapes, which protects the spiral organ located in the inner ear from excessive tremors and harsh sounds.

The bone chain has two functions:
1) bone conduction of sound and
2) the mechanical transmission of sound vibrations to the oval window of the vestibule, fenestra vestibuli.

The ear is a complex organ that performs two functions: listening, through which we perceive sounds and interpret them, thus communicating with the environment; and maintaining body balance.

Auricle - Captures and directs sound waves into the internal auditory canal;

Back labyrinth, or semicircular canals - directs movements to the head and brain to regulate the balance of the body;

Front mazeor snail - contains sensory cells, which, capturing the vibration of sound waves, transform mechanical impulses into nerve impulses;

Auditory nerve - directs general nerve impulses to the brain;

Middle ear bones: hammer, anvil, stapes - receive vibrations from auditory waves, amplify them and transmit them to the inner ear;

External auditory canal - picks up sound waves coming from outside, and directs them to the middle ear;

Eardrum - a membrane that vibrates from sound waves entering it and transfers vibrations along the ossicles in the middle ear;

Eustachian tube - a channel connecting the eardrum with the pharynx and allowing support
in equilibrium, the pressure created in the middle ear, with the pressure of the environment.

The ear is divided into three sections, the functions of which are different.

; the outer ear consists of the auricle and the external auditory canal, its purpose is to capture sounds;
; the middle ear is located in the temporal bone, is separated from the inner ear by a movable membrane - the eardrum - and contains three articular bones: a malleus, anvil and stapes, taking part in the transmission of sounds to the cochlea;
; the inner ear, also called the labyrinth, is formed of two departments that perform various functions: the front labyrinth, or the cochlea, where the organ of Corti is responsible for hearing, and the posterior labyrinth, or semicircular canals, in which impulses are produced that take part in maintaining equilibrium bodies (article "Balance and hearing")

The inner ear, or labyrinth, consists of a very strong bone skeleton, an ear capsule, or a bone labyrinth, inside of which there is a membrane mechanism with a structure similar to bone, but consisting of membrane tissue. The inner ear is hollow but filled with fluid: there is a perilymph between the bone labyrinth and the membrane, while the labyrinth itself is filled with the endolymph. The front labyrinth, whose bone form is called the cochlea, contains structures that generate auditory impulses. The back labyrinth, which takes part in regulating the balance of the body, has a bone skeleton consisting of a cubic part, a vestibule and three channels in the form of an arc - semicircular, each of which includes a space with a flat plane.

The cochlea, so named because of its spiral shape, contains a membrane consisting of channels filled with liquid: a central channel of triangular cross section and a curl containing an endolymph located between the vestibule staircase and the tympanic staircase. These two stairs are partially separated, they pass into the large canal of the cochlea, covered with thin membranes that separate the inner ear from the middle: the tympanic staircase begins with an oval window, while the vestibule reaches the rounded window. The cochlea, which has a triangular shape, consists of three faces: the upper, which is separated from the staircase by the Reisner membrane, the lower, separated by the main membrane from the tympanic ladder, and the side, which is attached to the shell and is a vascular groove producing endolymph. Inside the cochlea there is a special auditory organ - the corti (the mechanism of sound perception is described in detail in the article "