Sound waves are vibrations that are transmitted with a certain frequency in all three environments: liquid, solid and gaseous. For human perception and analysis, there is an organ of hearing - the ear, which consists of the outer, middle and inner parts, capable of receiving information and transmitting it to the brain for processing. This principle of work in the human body is similar to that characteristic of the eyes. The structure and functions of the visual and auditory analyzers are similar to each other, the difference is that the hearing does not mix sound frequencies, perceives them separately, rather, even separating different voices and sounds. In turn, the eyes connect the light waves, while receiving different colors and shades.
Auditory analyzer, structure and functions
Photos of the main departments of the human ear you can see in this article. The ear is the main organ of hearing in a person; it receives sound and transfers it further to the brain. The structure and functions of the auditory analyzer are much wider than the capabilities of the ear alone; this is the coordinated work of transmitting impulses from the eardrum to the stem and cortical parts of the brain, which are responsible for processing the obtained data.
The body responsible for the mechanical perception of sounds consists of three main departments. The structure and functions of the departments of the auditory analyzer are different, but they perform one common task - the perception of sounds and their transmission to the brain for further analysis.
The outer ear, its features and anatomy
The first thing that meets sound waves on the way to perceiving their semantic load is the outer ear. Its anatomy is quite simple: it is the auricle and the external auditory meatus, which is the connecting link between it and the middle ear. The auricle itself consists of a cartilaginous plate 1 mm thick, covered with perichondrium and skin, it is devoid of muscle tissue and cannot move.
The lower part of the shell is the earlobe, it is fatty tissue, covered with skin and penetrated by many nerve endings. The conch smoothly and funnel passes into the auditory meatus, bounded by the tragus in front and the anti-tragus in the back. In an adult, the passage is 2.5 cm in length and 0.7–0.9 cm in diameter; it consists of the inner and membranous-cartilaginous sections. It is limited to the eardrum, behind which the middle ear begins.
The membrane is an oval-shaped fibrous plate on the surface of which elements such as a malleus, posterior and anterior folds, umbilicus, and short process can be distinguished. The structure and functions of the auditory analyzer, represented by such a part as the outer ear and the eardrum, are responsible for capturing sounds, their primary processing and transferring them further to the middle part.
Middle ear, its features and anatomy
The structure and functions of the departments of the auditory analyzer are radically different from each other, and if everyone is familiar with the anatomy of the external part, then more attention should be paid to studying information about the middle and inner ear. The middle ear consists of four air cavities, interconnected, and the anvil.
The main part that performs the basic functions of the ear is the tympanic cavity, combined with the nasopharynx of the auditory tube, through this hole ventilation of the entire system takes place. The cavity itself consists of three chambers, six walls and an auditory ossicle, which, in turn, is represented by a hammer, anvil and stirrup. The structure and functions of the auditory analyzer in the middle ear region transform the sound waves received from the outer part into mechanical vibrations, after which they transfer them to the fluid, which fills the cavity of the inner part of the ear.
Inner ear, its features and anatomy
The inner ear represents the most complex system of all three departments of the hearing aid. It looks like a labyrinth, which is located in the thickness of the temporal bone, and is a bone capsule and a membranous formation included in it, which completely repeats the structure of the bone labyrinth. Conventionally, the entire ear is divided into three main parts:
- middle labyrinth - vestibule;
- front labyrinth - snail;
- back labyrinth - three semicircular canals.
The labyrinth completely repeats the structure of the bone part, and the cavity between the two systems is filled with a perilymph, reminiscent in its composition of plasma and cerebrospinal fluid. In turn, the cavities in the membranous labyrinth itself are filled with endolymph, similar in composition to intracellular fluid.
Auditory analyzer, ear structure, inner ear receptor function
Functionally, the work of the inner ear is divided into two main functions: transmission of sound frequencies to the brain and coordination of human movements. The main role in transmitting sound to parts of the brain is played by the cochlea, the different parts of which perceive vibrations with different frequencies. All these vibrations are absorbed by the basilar membrane, covered with hair cells with bundles of stereolithium at the apex. It is these cells that turn vibrations into electrical impulses that travel to the brain through the auditory nerve. Each hair of the membrane has a different size and only accepts sound of a strictly defined frequency.
The principle of the vestibular apparatus
The structure and functions of the auditory analyzer are not limited only to the perception and processing of sounds, it plays an important role in the whole motor activity of a person. For the work of the vestibular apparatus, on which the coordination of movements depends, the fluids that fill part of the inner ear are responsible. The main role here is played by endolymph, it works on the principle of a gyroscope. The slightest tilt of the head sets it in motion, it, in turn, makes the otoliths, which irritate the hairs of the ciliary epithelium, move. With the help of complex neural connections, all this information is transmitted to the departments of the brain, then its work on coordination and stabilization of movements and balance begins.
The principle of coordinated work of all chambers of the ear and brain, the transformation of sound vibrations into information
The structure and functions of the auditory analyzer, which can be briefly studied above, are aimed not just at capturing sounds of a certain frequency, but at converting them into information that is understood by the human mind. All conversion work consists of the following main steps:
- The capture of sounds and their movement along the auditory canal, stimulating the eardrum to oscillate.
- Vibration of the three auditory ossicles of the inner ear caused by vibrations of the eardrum.
- Fluid movement in the inner ear and vibrations of hair cells.
- The conversion of vibrations into electrical impulses for their further transmission through the auditory nerves.
- The movement of pulses along the auditory nerve into the brain and converting them into information.
Auditory Cortex and Information Analysis
No matter how smooth and perfect the work of all departments of the ear would be, everything would be pointless without the functions and work of the brain, which converts all sound waves into information and a guide to action. The first thing that meets the sound in its path is the auditory cortex, located in the superior temporal gyrus of the brain. Here are the neurons that are responsible for the perception and separation of all ranges of sound. If due to any damage to the brain, such as a stroke, these sections are damaged, then a person may become hard of hearing or even lose his hearing and the ability to perceive speech.
Age-related changes and features in the work of the auditory analyzer
With an increase in a person’s age, the work of all systems changes, the structure, functions and age features of the auditory analyzer are no exception. In people aged, hearing loss is often observed, which is considered physiological, that is, normal. This is not considered a disease, but only an age-related change called persiacusis, which does not need to be treated, but can only be adjusted using special hearing aids.
There are a number of reasons why hearing loss in people who have reached a certain age threshold is possible:
- Changes in the outer ear - thinning and flabbiness of the auricle, narrowing and curvature of the ear canal, loss of its ability to transmit sound waves.
- Thickening and clouding of the eardrum.
- Decreased mobility of the ossicles of the inner ear, ossification of their joints.
- Changes in the parts of the brain responsible for the processing and perception of sounds.
In addition to the usual functional changes in a healthy person, problems can be exacerbated by the complications and consequences of otitis media, they can leave scars on the eardrum, which provoke problems in the future.
After medical scientists studied such an important organ as the auditory analyzer (structure and functions), deafness caused by age has ceased to be a global problem. Hearing aids, aimed at improving and optimizing the work of each of the departments of the system, help older people live a full life.
Hygiene and hearing care
To keep your ears healthy, you need timely and accurate care for them, as well as for your whole body. But, paradoxically, in half the cases, problems arise precisely because of excessive care, and not because of its lack. The main reason is inept equipment with ear sticks or other means for mechanically cleaning up the accumulated sulfur, grazing of the tympanic septum, its scratches and the possibility of accidental perforation. To avoid such injuries, only the outside of the aisle should be cleaned without using sharp objects.
To preserve hearing in the future, it is better to adhere to safety rules:
- Limited listening to music using headphones.
- The use of special headphones and ear plugs when working in noisy enterprises.
- Protection from getting water in your ears while swimming in the pool and ponds.
- Prevention of otitis media and catarrhal diseases of the ears in the cold season.
Understanding the principles of the auditory analyzer, observing the rules of hygiene and safety at home or at work will help preserve the hearing and not face the problem of its loss in the future.