The human hearing organ includes three main parts. The first is the outer ear. It picks up sound vibrations. The task of the middle section is to transmit the sound wave to the inner ear. The middle section converts this irritation into a nerve impulse.
Inner ear: what is it and what is its composition?
It is located in the cavity of the temporal bone, namely between the tympanic cavity and the internal auditory meatus. The assumption that this organ performs only the function of hearing is misleading. Few people know that he has the responsibility to maintain balance when moving. The structure of the inner ear includes structures that are two labyrinths: bone and membranous (located inside the first). Between these formations there is a space that is filled with a specialized fluid capable of transmitting auditory vibrations - perilymph.
Component parts
What is in the inner ear? Each of the labyrinths has its own special structures. ATbone secretion:
- anticipation;
- semicircular canals;
- snail;
The first of these structures is an extended intermediate part of the bone labyrinth. It is considered the connecting link between the cochlea (communicated at the back) and the semicircular canals (connected at the front). The lateral part of the vestibule has two openings: the window of the vestibule and the cochlea, and the medial part has two cavities resembling a sphere and an ellipse.
The back of the bony labyrinth is represented by semicircular canals. They are located in three mutually perpendicular planes (sagittal, horizontal and frontal). This is due to the fact that a person, moving in space, is also located in three planes. The canals are connected to the vestibule by means of extended legs.
There is a snail in front. It has a spiral shape. Starting from the window of the vestibule, the cochlea makes two and a half turns around the rod, which has a bone base. From the bone rod into the canal of the cochlea there is a spiral plate (consists of bone tissue) in order to divide this structure into two ladders: the vestibule and the tympanic. At the top of the cochlea they join.
In addition to bone structures, the structure of the inner ear includes formations consisting of soft tissues. This is the membranous labyrinth. It is filled with endolymphatic fluid and is divided into four compartments:
- Spherical pouch.
- Elliptical pouch
- Semicircularducts.
- Cochlear duct.
The two pouches mentioned above can be referred to as "queenies". They are located in the recesses of the vestibule and communicate with each other. The sac in the form of a sphere is connected with the cochlear canal (one of the parts of the bony labyrinth), and the elliptical one is connected with the ducts of the semicircular canals. If the channels ended in a leg, then the ducts ended in an ampulla. One duct can only have one ampoule.
In turn, the cochlear canal has its own duct. If you make a cross section along it, you get a triangle. To understand how a sound wave is conducted, it is worth disassembling the main parts of the triangle. There are two parts in the duct: upper and lower. The function of the top is isolation from the staircase of the vestibule, the bottom - from the tympanic. Also on the lower wall is the basilar membrane, on which fibrous formations lie, in order to perform a resonating function. The structure of the inner ear includes a formation that converts sound vibrations into nerve impulses. This is the organ of Corti. It is a group of hair cells covered with a membrane.
Functions of the inner ear
This organ of the human body is used for:
- Sound perception.
- Balance and coordination in space.
In the absence of any of the listed functions, the full existence of a person will not be possible. He will not be able in this case to reunite with the outside world. Receptor cells of the hearing aid are responsible for the perception of sound vibrations, for coordination- receptor cells of the semicircular canals and their formations.
The path of sound through the auditory analyzer
The ear is the first in the path of a sound wave, which, due to its large area, picks up vibrations. Then, having hit the tympanic membrane, they make it oscillate, which allows the wave to be transmitted to the system of auditory ossicles, which will amplify the oscillatory movements many times over and transmit it to the window of the vestibule. The perilymph will begin to move. Vibrations from the perilymph are transmitted to the endolymph of the membranous labyrinth. The hair cells are excited by the movement of the fluid and convert the mechanical energy of the movement into an electrical impulse, which is transmitted along the auditory nerve to the cerebral cortex, where the analysis takes place and the response is reproduced.
Vestibular analyzer
The composition of the inner ear also includes sensitive hair cells, together with a jelly-like substance, which are located in the membranous labyrinth. In ampoules, these groups of cells are called scallops. They capture various kinds of angular accelerations (accelerations of rotation). In the uterus, these cells are located in the form of spots and are represented by the otolith apparatus, since crystals of calcium s alts are found in the jelly-like substance. This sac-uterine apparatus responds to changes in head position, body rotation, and linear acceleration.
At the moment of body movement, cell receptors are excited by the movement of endolymph. As a result, a nerve impulse is generated, which is transmitted to neurons.vestibular node, lying at the bottom of the auditory canal, and then in the central nervous system: spinal cord and brain. When information is received by neurons in the spinal cord, uncontrolled muscle contractions occur that regulate the coordination and movement of the body.
Summing up
So, we have considered the general information about the inner ear. This body has a complex structure. As already mentioned, the composition of the inner ear includes a number of structures, both bone and consisting of other tissues. The two main functions of the inner ear are auditory and vestibular. If the structures of the ear are damaged due to injuries or diseases, not only a violation of the perception of sounds can occur, but also a distortion of the perception of the position of the body in space, loss of coordination. Therefore, you should be careful about the state of the organs of the auditory and vestibular analyzer.
