Ear: Auditory System and Semicircular Canals

1402 WordsMar 17, 20046 Pages
The ear is an organ of the body that is used for hearing and balance. It is connected to the brain by the auditory nerve and is composed of three divisions, the external ear, the middle ear, and the inner ear. The greater part of which is enclosed within the temporal bone. The ear is looked upon as a miniature receiver, amplifier and signal-processing system. The structure of the outer ear catching sound waves as they move into the external auditory canal. The sound waves then hit the eardrum and the pressure of the air causes the drum to vibrate back and forth. When the eardrum vibrates its neighbour the malleus then vibrates too. The vibrations are then transmitted from the malleus to the incus and then to the stapes. Together…show more content…
This is called the Eustachian tube. This tube is made up of both bone and hyaline cartilage and connects to the middle ear with the nasopharynx which is the upper part of the throat. This is generally closed at the medial end. When swallowing or yawning occurs, it opens. This allows the air to enter or leave the middle ear until the pressure in the middle ear equals the atmospheric pressure. When both pressures are balanced, the eardrum then vibrates freely as the sound waves hit it. If these pressures are not balanced, an intense pain, hearing impairment, ringing in the ears or vertigo could develop. The Inner Ear or Labyrinth- consists of two main divisions… an outer bony labyrinth which encloses an inner membranous labyrinth and the bony labyrinth which is a series of cavities in the temporal bone and it is divide into three areas. These are the semicircular canales, the vestibule and the cochlea. Both the semicircular canals and the vestibule contain receptors for equilibrium. The Cochlea contains receptors for hearing. The labyrinth is lined with periosteum and contains perilymph. This fluid surrounds the membranous labyrinth, which is a series of sacks and tubes inside of the bony labyrinth and has the same common form. The vestibule is the oval central proportion of the bony labyrinth. Attached to the vestibule are three bony semicircular canals. They are named based upon their positions,

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