Normal Hearing Function

Sound is sent through the air as sound waves and are collected by the outer ear and sent down the ear canal to the eardrum.

• The sound waves cause the eardrum to vibrate, which sets the three tiny bones in the middle ear into motion.
• The motion of the 3 bones triggers the fluid in the inner ear, or cochlea, to move.
• The movement of the fluid in the inner ear causes the hair cells in the cochlea to bend. The hair cells alter the motion into electrical impulses.
• These electrical impulses are sent to the auditory nerve and up to the brain, where they are interpreted as sound.

The Outer Ear

The part of the outer ear that we see is called the pinna, or auricle. The pinna, with its grooves and ridges, offers a natural volume boost for sounds in the 2000 to 3000 Hz frequency variety, where we view lots of consonant noises of speech.

The Middle Ear

The eardrum, or tympanic membrane (TM), is the dividing structure between the outer and middle ear. Although it is a very thin membrane, the eardrum is comprised of three layers to increase its strength. The ossicles are the three tiny bones of the middle ear situated straight behind the tympanic membrane. These are the three tiny bones (smallest in the body) in the center ear: malleus (hammer), incus (anvil,) and stapes (stirrup) and their job is to additional enhance the noise. These three bones form a connected chain in the center ear. The malleus is embedded in the innermost layer of the tympanic membrane, and the stapes is connected to a membranous window of the inner ear, called the oval window. The ossicles equate mechanical vibrations got at the eardrum into the inner ear.

The Inner Ear

The inner ear is an organ located deep within the temporal bone, which is the bone of the skull on both sides of the head above the outer ear. The inner ear has two primary structures: the semicircular canals and the cochlea.the 2000 to 3000 Hz frequency variety, where we perceive numerous consonant sounds of speech.