Human outer ear. The structure and functions of the ear

At first glance, the structure of the human ear outwardly looks quite simple, but in fact its anatomy has complex mechanism. Of everything human body The hearing aid is the most sensitive organ. The hearing aid contains more than thirty thousand nerve cells, which allows you to react to the slightest changes in the environment.

The structure of the ear and its functions

Structure auricle and the functions of the hearing aid are quite complex. Although every person in anatomy lessons studied the structure of the ear and in in general terms knows how it works, but still, until the end, scientists have not revealed how exactly the conversion of sound signals occurs. The structure of the human ear consists of several main parts:

• outer ear;
• inner ear.

Each part is responsible for a specific function of the hearing aid. The outer part of the hearing aid is a receiver, the middle part is an amplifier of sound signals, and the hidden part is a kind of sensor.

The structure of the middle ear

The middle ear is one of the main parts of the hearing aid, which was formed from the maxillofacial bones. This provides a change in the fluctuation of the fluid that fills inner part ear. main part The human hearing aid is considered to be the tympanic cavity, which is a centimeter space in the temple area. Also, the structure of the middle ear includes auditory bones, in medicine they have names: hammer, anvil and stirrups. It is these three bones that transmit sound impulses from the eardrum to the hidden part of the ear.
The auditory bones are the smallest bones in the skeleton and form a kind of chain that transmits sound impulses. One side of the malleus is integral with the membrane, while the other side of this bone is closely connected to the incus. The longest side of the bone, called the anvil, is connected to the stirrup. The middle ear is directly connected to the nasopharynx with the help of special tubes. This tube has the function of equalizing air pressure on both sides of eardrum. If the external pressure changes, then the person's ears are "laid".

The middle part of the ear is responsible for amplifying sound signals. The auditory ossicles, located in the middle ear, are important for conducting and transmitting sound vibrations. In the region of the middle ear there are muscles that also play a lot important role. These muscles perform a protective, tonic and accommodative function. In this area, diseases and pathologies are most often observed, for example, acute or chronic catarrh, otitis different forms And so on. Inflammatory processes also often occur due to injuries.

Outer ear, structure, functions and age features

The structure of the outer ear includes the auditory canal located inside the auricle. Herself outer part The human ear is made up of elastic cartilage. This cartilage tissue expresses the shape of the human ear. Bottom part auricle ends with a lobe. Hidden inside is a hearing aid made up of cartilage and bone tissue. The cartilaginous part is a continuation of the groove-like cartilage. This passage is open at the top and back, and is attached to the edge temporal bone.

cartilaginous part ear canal makes up about a third of the entire length, and the bone makes up two thirds of the entire length. This interval is rich not only sebaceous glands, but also some other glands that secrete a special yellowish discharge. The tympanic membrane is located between the auricle and the middle ear.

The tympanic membrane of a mature person is a translucent plate with a small funnel and has an oval shape with two diameters of eleven and nine millimeters. The outer part of this membrane is covered with a very thin skin, and with inside covered with mucous membrane. From above, the membrane does not have fibers of fibrous origin. The outer ear is supplied with blood by two arteries. Lymph enters from the outer ear into the lymph nodes, which are located in front of and behind the ear.

The outer ear has age features. Approximately at the sixth week after fertilization begins to be laid auditory analyzer and develop the functions of the ear receptors, and by the twentieth week of pregnancy, the function of the ear receptors is fully formed. In the first months after birth, the babies react only to a rather loud noise, after a few months the child begins to respond in his own way to sounds outside of sight and turns to the source of the noise. By the age of nine months, the child clearly distinguishes the voices of loved ones.

The structure of the cochlea

The design of the cochlea is a kind of labyrinth, consisting not of a bone shell, but also of a formation that duplicates this shell. The bone membrane consists of the semicircular canals, the vestibule and the cochlea. The cochlea of ​​the auricle consists of a bone spiral formation in two and a half curls. The width of this cochlea is about ten millimeters, and the height reaches five millimeters. The length of the snail spiral is slightly more than three centimeters. The cochlea begins in the bone rod, and the spiral plate goes inside the labyrinth. This formation begins quite spacious and gradually decreases towards the end. The cochlear helix divides into two canals due to the basilar membrane. The superior canal begins at the oval membrane and ends at the very top of the cochlea. The second channel starts at this vertex and ends at the rounded window. The two canals are connected at the top by a small opening and are filled with perilymph. There is a vestibular membrane that divides upper channel for two bosoms.

The main task of the cochlea is to transmit nerve impulses from the middle ear to the brain. When sound vibrations reach the ear, they collide with the membrane. This collision provokes an oscillation that passes through the three auditory bones. With these impulses, the cilia of the hair cells in the sound analyzer begin to move and irritate the integumentary membrane, which provokes the transmission of sound vibrations to the human brain. The human ear contains rather small elements. There is also a special covering of the ear canal. This coating contains vital important glands that secrete a protective secret. The eardrum serves as a kind of barrier separating the two parts of the hearing aid.

One part has the functions of receiving and transmitting a sound signal to the middle part of the ear, and is also capable of directing sound signals in the hidden part of the ear. Most often, the outer part suffers from such diseases and injuries as: eczema, otitis media, herpes, and so on. An important role is played by the vestibular analyzer, because it is essential for regulating the position of the movement of the body and the vestibular apparatus. This area is located in the inner ear. Due to the vestibular spinal nerve cords somatic reactions occur that maintain the person's balance.

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 turn into sound images. A person is able to catch the sound, the minimum frequency of which is 16 Hertz. The limiting threshold of perception is sound waves with a frequency of no more than 20 thousand Hertz.

The human ear is made up of three parts:

• outdoor;
• middle;
• internal.

Each of them performs its own function of sound transmission. The ears also help with balance. it paired organ, which is located in the thickness of the temporal bone cranium. 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 external auditory meatus and the auricle. The auricle is a very resilient and elastic cartilage, which 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 on the cartilage.

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

The external auditory canal is lined with skin huge amount sebaceous and sulfuric glands. They secrete a secret that helps protect human ear from different kind mechanical, infectious, thermal and chemical influences.

The ear canal ends at the tympanic membrane. It is the 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. So the signal goes to the middle ear.

Middle ear anatomy

The middle ear is small 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 hammer, stirrup and anvil. The hammer has a tiny handle that communicates with the eardrum. Its head is connected to the anvil, which is connected to the stirrup. 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 amplify the sound to make it sound clearer and richer.

The Eustachian tube connects the middle ear to the nasopharynx. The main function of this pipe is to maintain a balance between atmospheric pressure and those that arise in the tympanic cavity. This allows you to more accurately transmit sounds.

The inside of the human ear

Structure inner ear the most complex part of the entire hearing aid, and this department plays the most important role. It is located in the stony 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 is oval, opens into the vestibule, and the second, which has round shape, into the spiral canal of the cochlea.

The cochlea itself, which is a tube in the form of a spiral, has a length of 3 cm and a width of 1 cm. Its inner part is filled with liquid. There are hair cells on the walls of the cochlea. hypersensitivity. They may look like cylinders or cones.

The inner ear contains the semicircular canals. Often in medical literature you can find another name for them - balance organs. They are three tubes, curved 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 are named:

• sagittal;
• frontal;
• horizontal.

The vestibule and channels are part of the vestibular apparatus, which allows us to keep balance and determine the position of the body in space. Hair cells are immersed in the fluid in the semicircular canals. With the slightest movement of the body or head, the fluid moves, pressing on the hairs, due to which impulses are formed at the ends of the vestibular nerve, which instantly enter the brain.

Clinical anatomy of sound production

The sound energy that has entered 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 frequency and length. The short waves are 20,000 Hz and the longest are 16 Hz. Therefore, each hair cell is tuned to a specific frequency. There is a 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 propagate instantly. This is facilitated by the structural features of the human ear. The result is hydrostatic pressure. It contributes to the fact that the integumentary plate of the organ of Corti, located in the spiral canal of the inner ear, shifts, due to which the filaments of the stereocilia, which gave the name to the hair cells, begin to deform. They are excited and transmit information using primary sensory neurons. The ionic composition of the endolymph and perilymph, special fluids in the organ of Corti, forms a potential difference that reaches 0.15 V. Thanks to this, we can hear even small sound vibrations.

Hair cells are closely related to nerve endings, which are part of auditory nerve. Due 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 transmit a certain sound frequency. Each of the 10,000 fibers of the auditory nerve tries to transmit to the central nervous system its momentum, 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 perceive only 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 representations and images are created. Sounding music or a memorable 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 lead to the loss of the ability to hear sounds. Therefore, even with minor changes in the perception of sound signals, you need to contact the ENT to determine possible pathology. Only he will give qualified advice and appoint proper treatment.

Causes of disturbances in the perception of sounds

The anatomy of the human ear determines its function. 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. Deaf and hard of hearing people, although they can perceive sound information from the outside by the movement of the lips of the interlocutor, do not capture emotions, conveyed by words. Hearing loss negatively affects vestibular apparatus, it becomes more difficult for a person to navigate in space, since he is not able to perceive the changes that sound warns about: for example, the approach of a car.

Weakening or total loss The ability to hear can be caused by such reasons:

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

Inflammatory processes are often accompanied severe pain. When they are distributed to internal department auditory receptors are affected, resulting in deafness.

The ear is a paired organ that performs the function of perceiving sounds, and also controls balance and provides orientation in space. Located in temporal region skull, has a conclusion in the form of external auricles.

The structure of the ear includes:

• outer;
• average;
• internal department.

The interaction of all departments promotes the transfer sound waves, converted into a neural impulse and entering the human brain. Ear anatomy, analysis of each of the departments, makes it possible to describe complete picture structure of the auditory organs.

This part of the general auditory system is the pinna and ear canal. The shell, in turn, consists of adipose tissue and skin, its functionality is determined by the reception of sound waves and subsequent transmission to hearing aid. This part of the ear is easily deformed, which is why it is necessary to avoid any rough physical influences as much as possible.

The transmission of sounds occurs with some distortion, depending on the location of the sound source (horizontal or vertical), this helps to better navigate the environment. Next, behind the auricle, is the cartilage of the outer ear canal (the average size 25-30 mm).

To remove dust and mud deposits, the structure has sweat and sebaceous glands. The tympanic membrane acts as a connecting and intermediate link between the outer and middle ear. The principle of operation of the membrane is to capture sounds from the external auditory canal and turn them into vibrations of a certain frequency. The converted vibrations pass into the region of the middle ear.

The structure of the middle ear

The department consists of four parts - the tympanic membrane itself and the auditory ossicles located in its area (hammer, anvil, stirrup). These components ensure the transmission of sound to the inner part of the hearing organs. The auditory ossicles form a complex chain that carries out the process of transmitting vibrations.

The structure of the ear of the middle compartment also includes the Eustachian tube, which connects this department with the nasopharynx. It is necessary to normalize the pressure difference inside and outside the membrane. If the balance is not maintained, it is possible or rupture of the membrane.

The structure of the inner ear

The main component - the labyrinth - is a complex structure in its form and functions. The labyrinth consists of the temporal and bone parts. The structure is placed in such a way that temporal part is located inside the bone.

The inner part contains an auditory organ called the cochlea, as well as the vestibular apparatus (responsible for general balance). The department in question has several more auxiliary parts:

• semicircular canals;
• uterus;
• stirrup in oval window;
• round window;
• drum ladder;
• spiral canal of the cochlea;
• pouch;
• entrance staircase.

The cochlea is a bony canal of a spiral type, divided into two identical parts by a septum. The partition, in turn, is divided by stairs connected from above. The main membrane is made up of tissues and fibers, each of which responds to a specific sound. The structure of the membrane includes an apparatus for the perception of sound - the organ of Corti.

Having considered the design of the hearing organs, we can conclude that all divisions are mainly connected with the sound-conducting and sound-receiving parts. For the normal functioning of the ears, it is necessary to observe the rules of personal hygiene, avoid colds and injuries.

The ear is considered the most complex organ human body. It allows you to perceive sound signals and controls the position of a person in space.

Anatomical structure

The organ is paired, and it is located in the temporal region of the skull, in the region of the pyramidal bone. Conventionally, the anatomy of the inner ear can be divided into three main areas:

• The inner ear, consisting of several dozen elements.
• Middle ear. This part includes the tympanic cavity (membrane) and special auditory ossicles(the smallest bone in the human body).
• Outer ear. It consists of the external auditory meatus and the auricle.

The inner ear includes two labyrinths: membranous and bony. The bone labyrinth consists of elements that are hollow inside, connected to each other. The labyrinth is perfectly protected from external influences.

A membranous labyrinth is placed inside the bony labyrinth, identical in shape, but smaller in size.

The cavity of the inner ear is filled with two fluids: perilymph and endolymph.

• Perilymph serves to fill the interlabyrinth cavities.
• Endolymph is thick clear liquid, which is present in the membranous labyrinth and circulates through it.

The inner ear is made up of three parts:

• snail,
• vestibule;
• semicircular canals.

The structure of the semicircular canals begins from the center of the labyrinth - this is the vestibule. At the back of the ear, this cavity connects to the semicircular canal. On the side of the wall there are "windows" - internal holes cochlear canal. One of them is connected to the stirrup, the second, which has an additional tympanic membrane, communicates with the spiral canal.

The structure of the snail is simple. The spiral bone plate is located along the entire length of the cochlea, dividing it into two sections:

• drum ladder;
• entrance staircase.

The main feature of the semicircular canals is that they have legs with ampullae expanding at the end. Ampoules closely adjoin to bags. The fused anterior and posterior canals exit into the vestibule. The vestibulocochlear nerve serves to transmit nerve impulses.

Functions

Scientists have found that with the process of evolution, the structure of the inner ear has also changed. In the body modern man the inner ear will have two functions.

Orientation in space. The vestibular apparatus located inside the auricle helps a person navigate the terrain and keep the body in the right position.

Here the district canals and the vestibule will be involved.

Hearing. Inside the cochlea, there are processes responsible for the perception of sound signals by the brain.

Perception of sounds and orientation

The shocks of the tympanic membrane are caused due to the movement of the endolymph. Perelymph that moves up the stairs also affects the perception of sound. The vibrations irritate the hair cells of the organ of Corti, which converts audible sound signals directly into nerve impulses.

The human brain receives information and analyzes it. Based on the information received, a person hears a sound.

The vestibular apparatus is responsible for the position of the body in space. Roughly speaking, it acts like a building level used by workers. This organ helps maintain the balance of the body. The vestibule and semicircular canals have a very complex systematic structure; inside them are special receptors called scallops.

It is the scallops that perceive the movements of the head and react to them. In this they resemble the hair cells found in the cochlea. Irritation occurs due to the presence of a jelly-like substance in the scallops.

When orientation in space is required, receptors in the vestibular sacs become active. The linear acceleration of the body induces the endolymph to move, which causes irritation of the receptors. Then, information about the beginning of the movement enters the human brain. Now there is an analysis of the received data. In the event that the information received from the eyes and from the vestibular apparatus differs, the person experiences dizziness.

Hygiene is essential for the proper functioning of the inner ear. It is the timely cleaning of the ear canal from sulfur that will keep the hearing in good condition.

Possible diseases

Diseases of the auricle impair a person's hearing, and also prevent the vestibular apparatus from working correctly. In the case when damage is done to the cochlea, sound frequencies are perceived, but incorrectly. Human speech or street noise is perceived as a cacophony of different sounds. This state of affairs not only makes it difficult normal functioning hearing, and could result in serious injury.

The cochlea can suffer not only from harsh sounds, but also from the effect of an airplane taking off, a sharp immersion in water, and many other situations.

AT this case damage to the eardrum will occur and. Thus, a person can lose hearing either for a long period, more than severe cases- for life. In addition, other troubles associated with the inner ear can happen.

Dizziness can be like independent reasons, and possible .

This disease has not been fully investigated and its causes are unclear, but the main symptoms are periodic dizziness, accompanied by clouding of the auditory function.

protruding ears. Despite the fact that this cosmetic nuance, many are puzzled by the problem of correction of protruding ears. In order to get rid of this disease undergoing plastic surgery.

Due to damage to the bone tissue (its proliferation), there is a decrease in the sensitivity of the ear, the appearance of noise, and a decrease in auditory function.

called acute or chronic inflammation auricle, provoking a violation of its functioning.

You can get rid of most "ear diseases" by observing. But, upon occurrence inflammatory processes a consultation with the attending physician or ENT is necessary.

Video: Inner ear

There are a lot of diseases that signal their development with pain in the ears. To determine what specific disease affected the organ of hearing, you need to understand how the human ear is arranged.

Diagram of the auditory organ

First of all, let's understand what an ear is. This is an auditory-vestibular paired organ that performs only 2 functions: the perception of sound impulses and responsibility for the position of the human body in space, as well as for maintaining balance. If you look at the human ear from the inside, its structure suggests the presence of 3 parts:

• external (external);
• average;
• internal.

Each of them has its own no less intricate device. Connecting, they are a long pipe penetrating into the depths of the head. Let us consider the structure and functions of the ear in more detail (the diagram of the human ear demonstrates them best).

What is the outer ear

The structure of the human ear (its outer part) is represented by 2 components:

• ear shell;
• external ear canal.

The shell is an elastic cartilage that completely covers the skin. It has a complex shape. In its lower segment there is a lobe - this is a small skin fold filled with fat inside. By the way, exactly outer part has the most high sensitivity to various types of injury. For example, for fighters in the ring, it often has a form that is very far from its original form.

The auricle serves as a kind of receiver for sound waves, which, falling into it, penetrate deep into the organ of hearing. Since it has a folded structure, the sound enters the passage with little distortion. The degree of error depends, in particular, on the place where the sound comes from. Its location is horizontal or vertical.

It turns out that more accurate information about where the sound source is located enters the brain. So, it can be argued that the main function of the shell is to catch sounds that should enter the human ear.

If you look a little deeper, you can see that the shell extends the cartilage of the external ear canal. Its length is 25-30 mm. Next, the cartilage zone is replaced by bone. outer ear completely lines skin covering which contains 2 types of glands:

• sulfuric;
• greasy.

The outer ear, the device of which we have already described, is separated from the middle part of the hearing organ by a membrane (it is also called the tympanic membrane).

How is the middle ear

If we consider the middle ear, its anatomy is:

• tympanic cavity;
• eustachian tube;
• mastoid process.

All of them are interconnected. The tympanic cavity is a space outlined by the membrane and the region of the inner ear. Its location is the temporal bone. The structure of the ear here looks like this: in the anterior part, there is a union of the tympanic cavity with the nasopharynx (the function of the connector is performed by the Eustachian tube), and in its posterior part, with the mastoid process through the entrance to its cavity. Air is present in the tympanic cavity eustachian tube gets there.

The anatomy of the ear of a person (child) up to 3 years old has a significant difference from how the ear of an adult is arranged. Babies do not have a bone passage, and the mastoid process has not yet grown. The children's middle ear is represented by only one bone ring. Its inner edge has the shape of a groove. It just houses the tympanic membrane. In the upper zones of the middle ear (where there is no this ring), the membrane is connected to the lower edge of the scales of the temporal bone.

When the baby reaches the age of 3, the formation of his ear canal is completed - the structure of the ear becomes the same as in adults.

Anatomical features of the internal department

The inner ear is the most difficult part of it. The anatomy in this part is very complex, so she was given a second name - "membranous labyrinth of the ear." It is located in the stony zone of the temporal bone. It is attached to the middle ear with windows - round and oval. Comprises:

• vestibule;
• snails with the organ of Corti;
• semicircular canals (filled with fluid).

In addition, the inner ear, the structure of which provides for the presence of the vestibular system (apparatus), is responsible for constantly keeping the body in a state of balance by a person, as well as for the possibility of accelerating in space. vibrations that occur in oval window, are transmitted to the fluid that fills the semicircular canals. The latter serves as an irritant for the receptors located in the cochlea, and this already becomes the cause of the launch of nerve impulses.

It should be noted that the vestibular apparatus has receptors in the form of hairs (stereocilia and kinocilia), which are located on special elevations - maculae. These hairs are located one opposite the other. By shifting, stereocilia provoke the occurrence of excitation, and kinocilia help inhibition.

Summing up

In order to more accurately imagine the structure of the human ear, the diagram of the organ of hearing should be in front of the eyes. It usually depicts a detailed structure of the human ear.

Obviously, the human ear is a rather complex system, consisting of many different formations, each of which performs a number of important and truly irreplaceable functions. The diagram of the ear demonstrates this clearly.

Regarding the device of the outer part of the ear, it should be noted that each person has individual, genetically determined features that in no way affect main function hearing organ.

Ears need regular hygienic care. If you neglect this need, you can partially or completely lose your hearing. Also, lack of hygiene can lead to the development of diseases affecting all parts of the ear.