The organs of hearing allow a person to receive sound and analyze it. The ear is a complex organ consisting of three main parts and auditory receptors. Proper ear function allows you to recognize sound and transmit a signal to the brain.
Human Hearing Aid
The hearing aid has a complex structure and is considered to be a sound analyzer. Inside, a sound-conducting and sound-receiving part is distinguished. The conductive path of the auditory analyzer consists of the outer and middle ear, labyrinth windows, membrane and fluid of the inner ear. The receptive canal is made up of auditory nerves, hair cells, and brain neurons.
The conduction apparatus allows you to transmit a sound signal to the perceiving receptors, which send the signal and transform it into the central sections of the auditory analyzer.
The outer part of the ear consists of the auricle and the external auditory meatus. Its main purpose is to receive acoustic signals from the external environment. The middle part amplifies the signal, the inner part becomes the transmitter.
Outer ear
Auricle outerThe ear consists of elastic and elastic cartilage covered with skin. The skin has glands that secrete a special secret that protects the ear from mechanical, thermal damage, as well as from infection. The outer ear consists of the following parts:
- tragus;
- antitragus;
- curl;
- curl legs;
- anti-helix.
The pathway of the auditory analyzer ends in a dead end. The eardrum separates the outer and middle ear. The membrane begins to oscillate with acoustic signals, the energy of the signal is transmitted further to the middle part of the ear.
The bloodstream consists of 2 arteries, the outflow of blood occurs through the veins. Lymph nodes are located nearby: in front of and behind the auricle.
The outer part of the ear is designed to receive sounds, transmit them to the middle part and direct the sound wave to the inner part.
Middle ear
Departments of the auditory analyzer of the middle ear play a huge role in amplifying the signal. This part consists of the tympanic cavity and the Eustachian tube.
The tympanic membrane is the link between the external and internal auditory meatus of the middle ear. The tympanic membrane consists of 6 walls, in its cavity are the auditory ossicles:
- The hammer is equipped with a rounded head and transmits sound energy through the channel.
- The anvil consists of 2 processes of different lengths, interconnected. Its purpose is to transmit sound over the channel.
- The stirrup is formed from a small head, anvil and legs.
Arteries supply nutrients to the middle ear. Lymphatic vessels direct lymph to nodes located on the lateral wall of the pharynx and behind the ears. The complex structure of the middle ear allows vibrations to be transmitted and conducts sound to the receiver.
Muscles located in the region of the middle ear perform protective, tonic and accommodative functions. Thanks to them, the hearing organs are protected from loud annoying sounds. Also, the muscles support the bones and can adapt to sounds of different strength and wave vibrations.
Inner ear
The inner ear is the most complex structure of the hearing aid. It consists of the cochlea and the vestibular apparatus. The main purpose of the snail is to transmit sound. The vestibular apparatus determines the position of the body in space.
The cochlea is a bony labyrinth. This material is the most durable in the human body. In appearance, the snail resembles a cone 32 mm long. At the base, the diameter is 9 mm, at the top - 5 mm.
The internal structure of the cochlea resembles 2 ladders - the upper channel and the lower channel. Both channels are connected at the top of the cochlea by a narrow opening - the helicotrema. The cavities of the stairs are filled with a fluid similar in composition to that of the spinal cord.
Here is the secondary tympanic membrane. Through the spiral channel, the signal enters the organ of Corti and is transmitted to the ciliary bodies, which respond to sounds of different frequencies. With age, the number of hairs decreases, which contributes to hearing loss.
Vestibular apparatus
Anatomy of the auditory analyzer includes the vestibular apparatus. It consists of several cavities, inside of which a special liquid is located. The planes are called horizontal, frontal and sagittal. In the inner ear there are spots, combs and hairs that allow a person to perceive movement and orientation in space.
In the vestibular apparatus should be highlighted:
- semicircular canals;
- statocystic canals, which are represented by oval and round sacs.
Round pouch is located near the curl, oval - near the semicircular canals.
The analyzer of the vestibular apparatus becomes excited when a person moves in space. Thanks to nerve connections, somatic reactions are triggered. This is necessary to maintain muscle tone and control the balance of the body.
Reactions between the vestibular nucleus and the cerebellum determines the mobile reactions that appear during gaming, sports exercises. To keep balance, vision and well-coordinated muscle work are additionally required.
Conducting path of auditory analyzer
Receptors responsible for the perception of acoustic signals are located in the organ of Corti. It is located behind the cochlea and consists of hair cells located on the membrane.
The auditory analyzer pathway is required to transmit the audio signal. Neurons are located on the spiral ganglion of the cochlea. axons from nervecells enter the nuclei of the trapezoid body from both sides. Thus, the neurons are located in the nuclei of the trapezoid body.
The many axons are called the lateral loop. The funnel of the loop ends at the subcortical center. Axons respond to loud sound stimuli and carry out reflex muscle movements. The axons of the medial bodies send a signal to the cerebral cortex.
Functions
The function of the auditory analyzer is to convert sound waves into energy that can be transmitted through the nerves and processed by brain cells. The analyzer includes peripheral, conductive and cortical sections.
Peripheral division translates the sound wave into the energy of nervous excitation. Each part of the ear has its own function. The auricle directs the sound wave through the ear canal to the eardrum. At the same time, the outer part of the ear protects the conductive path of the auditory analyzer from temperature changes and mechanical impact.
Audio analyzer perceives sound waves with a frequency of 20 to 20 thousand per second. The higher the frequency, the higher the pitch. At high frequencies of sound vibrations, a sound wave passes through the conductive path of the auditory analyzer, which leads to the maximum amplitude of vibrations of the spiral membrane.
Anomalies in the development of the organ of hearing
Disturbances in the development of the ears can be both congenital and acquired. The most common middle ear anomalies are:
- deformity of the tympanic membrane;
- mal fusion of the auditory ossicles;
- absence or narrowness of the eardrum;
- presence of a bone plate instead of a tympanic membrane;
- missing part of the middle ear.
If the structure is wrong, the connection between the hammer and the anvil is broken. Because of this, hearing is completely impaired. Partial hearing loss occurs when the eardrum is deformed.
