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AlbanianHearing
Hearing is one of the five senses. It is a complex process that takes in sounds and assigns meaning to them. The human ear is fully developed at birth and responds to sounds that are very low as well as sounds that are very loud. Even in the womb, babies respond to sounds. The ability to listen is critical to being able to make sense of the world around us.So let's see how the ear and the hearing mechanism work.
The five parts of the hearing mechanism are:
- The outer ear
- The middle ear
- The inner ear.
- The auditory nerve
- The auditory processing of the brain.
The outer ear.
The outer ear consists of the pinna, and the ear canal (external auditory canal). The pinna - the "ear" we see on each side of our head - is made of cartilage and soft tissues, so that it maintains a certain shape, but at the same time is flexible. The pinna acts as a collector of the sound vibrations around us and channels the vibrations it collects into the ear canal. It helps us determine the direction and source of sound.
The ear canal is about an inch long and an inch in diameter. It extends from the eardrum to the eardrum (tympanic membrane). The external structure of the ear is made of cartilage and is covered with skin that contains the hairs and glands that secrete wax (cerumen). Hair and wax prevent foreign bodies, such as insects or dust, from entering the ear canal. Near the eardrum (tympanic membrane), the wall of the ear canal becomes bony and tightly covered by skin.
The middle ear
The middle ear begins with the eardrum, located at the end of the ear canal. The middle ear contains three tiny bones called ossicles. These three bones form a serial connection from the eardrum to the inner ear. As the sound waves meet the drum, it moves back and forth causing the ossicles to move. The sound wave is converted into mechanical vibrations.The first ostario, the hammer is connected to the drum. The hammer is connected to the second pin, the anvil, and then the anvil is connected to the third pin, the stirrup. The mechanical energy transmitted through the three bones causes the base of the stirrer to move in and out, at the same frequency as the incoming sound waves.
The middle ear is located in the mastoid part of the temporal bone (a skull bone on each side of the head) and is filled with air. A tube called the Eustachian tube runs from the front wall of the middle ear down to the back of the nose and throat (nasopharynx). This tube provides ventilation and access to outside air and equalizes the air pressure on both sides of the eardrum (the inner ear versus the outer ear. We have felt the Eustachian tube work in the air pressure differences in our ears , when yawning, chewing or when swallowing.
Due to the structure of the face and skull of children, the Eustachian tube is in a rather flat position between the middle ear and the nasopharynx rather than sloping down as in adults. The flat position of the tube in children creates a risk for infections traveling from the nasopharynx to the middle ear.
The inner ear
The inner ear contains the sensory organs for hearing and balance. The cochlea is the auditory part of the inner ear. The semicircular canals and sac are the balance part of the inner ear.
The auditory nerve carries impulses from the cochlea to a station in the middle of the brain, the cochlear nucleus, as well as to other brain pathways that terminate in the brain's auditory cortex. In the cochlear nucleus, nerve fibers from each ear form two tracts. One pathway ascends directly to the auditory cortex from one side (hemisphere) of the brain. The other crosses and ascends to the auditory cortex from the other side (hemisphere) of the brain. As a result, each hemisphere of the brain receives information from both ears.
The auditory system.
The auditory system deals with the processing of auditory information as it is conveyed to the brain. Central auditory system processes are responsible for the following behaviors:
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