Your hearing is active throughout the entire day. Hearing is not a sense that you can ‘turn on or off’; it works on several levels:
With our hearing we perceive background sounds, such as traffic noise, or more relevant sounds such as the ringing of an alarm clock. What is most important, however, is the ability to hear speech – to understand and communicate the ability to hear soft whispers to loud shouts for help. When our hearing ability is reduced, we are no longer able to hear sounds optimally.
The ear consists of three main parts:
Outer Ear
The Outer Ear includes the visible portion of the ear, called the auricle or pinna, and the ear canal. The pinna is made of cartilage and skin and is formed in the shape of a funnel in order to help gather sound from the environment. This helps in determining the direction of the source of the sound and directing sound down into the ear canal. Sound then travels down the ear canal and into the middle ear.
Middle Ear
The eardrum (tympanic membrane) is a very thin piece of skin that vibrates when sound reaches the membrane. The eardrum acts as the entrance to the air-filled middle ear cavity. Within the middle ear cavity there are three small bones – the malleus (hammer), incus (anvil) and stapes (stirrup). These three small bones move back and forth, transferring sound waves into the fluid-filled cavities of the inner ear. Because the middle ear is filled with air — the air pressure must be equalized to the environmental air pressure by the Eustachian tube, which connects the middle ear with the back of the throat and nose.
Inner Ear
The inner ear consists of both the hearing and balance organs. The hearing organ, called the cochlea, is filled with thousands of sensory hair cells that send neural impulses via the VIII (8th/auditory) nerve to the part of the brain responsible for understanding. These hair cells are pitch/frequency specific and allow the human ear to hear various loudness levels and pitches of sounds. The semi-circular canals — the organs of balance – are also located within the inner ear.
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