Hearing organs allow a person to receive sound and analyze it. The ear is a complex organ consisting of three main parts and auditory receptors. The correct operation of the ear 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 a sound analyzer. Inside, a sound-conducting and a sound-receiving part are distinguished. The pathway of the auditory analyzer consists of the outer and middle ear, labyrinth windows, the membrane and fluid of the inner ear. The perceptual canal consists of auditory nerves, hair cells and brain neurons.
The conducting device allows you to transmit an audio signal to the receptor receptors, which send the signal and transform it into the central departments of the auditory analyzer.
The outer part of the ear consists of the auricle and the external auditory canal. Its main purpose is to receive acoustic signals from the external environment. The middle part amplifies the signal, the internal becomes a transmitter.
Outer ear
The auricle of the outer ear consists of an elastic and elastic cartilage covered in skin. The skin has glands that secrete a special secret that protects the ear from mechanical, thermal damage, as well as infection. The outer ear consists of the following parts:
- tragus;
- anti-tragus;
- curl;
- curl legs;
- antihelix.
The pathway of the auditory analyzer ends in a dead end. The eardrum divides the ear into the outer and middle. The membrane begins to oscillate with acoustic signals, the signal energy is transmitted further to the middle part of the ear.
The bloodstream consists of 2 arteries, the outflow of blood occurs through the veins. Nearby are the lymph nodes: 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
The departments of the auditory analyzer of the middle ear play a huge role in amplifying the signal. This part consists of a tympanic cavity and an Eustachian tube.
The eardrum is the connecting link between the external and internal auditory meatus of the middle ear. The eardrum consists of 6 walls, the auditory ossicles are located in its cavity:
- 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 through the channel.
- The stirrup is formed from a small head, anvil and legs.
Arteries supply the middle ear with nutrients. Lymphatic vessels direct the lymph to the nodes located on the side of the pharynx and behind the ears. The complex structure of the middle ear allows you to transmit vibrations and conducts sound to the receiver.
The muscles located in the middle ear area perform protective, tonic and accommodation functions. Thanks to them, the hearing organs are protected from loud annoying sounds. The muscles also support the bones and can adapt to sounds of varying strength and wave vibrations.
Inner ear
The inner ear is the most complex structure of the hearing aid. It consists of a cochlea and a vestibular apparatus. The main purpose of the cochlea is sound transmission. The vestibular apparatus determines the position of the body in space.
The ear snail is a bone 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 of the ear resembles 2 stairs - the upper canal and the lower canal. Both channels are connected at the top of the cochlea with a narrow hole - helicotreme. The cavity of the stairs is filled with liquid, reminiscent of the cerebrospinal composition.
The secondary eardrum is also located here. Through a spiral channel, the signal enters the Corti's organ and is transmitted to the ciliary bodies, which respond to sounds of different frequencies. With age, the amount of hair decreases, which helps to reduce hearing.
Vestibular apparatus
The anatomy of the auditory analyzer includes the vestibular apparatus. It consists of several cavities, inside of which there is a special fluid. Planes are called horizontal, frontal and sagittal. In the inner ear there are spots, scallops and hairs that allow a person to perceive movements and orientation in space.
In the vestibular apparatus should be allocated:
- semicircular canals;
- statocystic channels, which are represented by oval and round sacs.
The round sac is located near the curl, the oval is near the semicircular canals.
The vestibular apparatus analyzer 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.
The reactions between the vestibular nucleus and the cerebellum are determined by the mobile reactions that appear during game, sports exercises. To maintain balance, vision and well-coordinated muscular work are additionally required.
Pathway of the auditory analyzer
The receptors responsible for the perception of acoustic signals are located in the Corti organ. It is located behind the cochlea and consists of hair cells located on the membrane.
The conductive path of the auditory analyzer is required to transmit an audio signal. Neurons are located on the spiral node of the cochlea. axons from nerve cells enter the nuclei of the trapezius in both directions. Thus, neurons are located in the nuclei of the trapezius.
Many axons are called the lateral loop. The loop funnel ends at the subcortical center. Axons respond to loud sound stimuli and perform reflex muscle movements. Axons of the medial bodies signal to the cerebral cortex.
Functions
The functions of the auditory analyzer are to convert sound waves into energy that can be transmitted along the nerves and processed by brain cells. The analyzer includes peripheral, conductor and cortical departments.
The peripheral section converts the sound wave into the energy of nervous excitation. Each part of the ear performs its function. The auricle directs a wave of sound into the ear canal to the eardrum. In this case, the outer part of the ear protects the conduction path of the auditory analyzer from changes in temperature and mechanical stress.
The auditory analyzer perceives sound waves with a frequency of 20 to 20 thousand per second. The higher the frequency, the higher the tonality. 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 the vibrations of the spiral membrane.
Hearing abnormalities
Disturbances in the development of the ears can be either congenital or acquired. The most common abnormalities of the middle ear are:
- eardrum deformity;
- abnormal fusion of auditory ossicles;
- absence or narrowness of the eardrum;
- the presence of a bone plate instead of an eardrum;
- lack of part of the middle ear.
If the structure is incorrect, the connection between the hammer and the anvil is broken. Because of this, the hearing is completely impaired. Partial hearing loss occurs when the eardrum is deformed.