Answer:
Ears are a pair of
statoacoustic organ meant for both balancing and hearing. In most mammals, the
external ear is a leap of tissue also called pinna. It is a part of auditory system.
The human ear consists of three main parts external ear, middle, ear and
internal ear.
Structure of Middle
Ear
The middle
ear contains three bones or ossicles-the malleus (hammer), incus (anvil) and stapes
(stirr-up). These bones are attached to one another in a chain-like fashion.
The malleus is attached to the tympanic membrane and the stapes is attached to
the oval window (a membrane beneath the stapes) of cochlea. These three
ossicles increase the efficiency of transmission of sound waves to the inner
ear.
The middle
ear also opens into the Eustachian tube, which connects with the pharynx and
maintains the pressure between the middle ear and the outside atmosphere,
Structure of
Internal Ear
The inner
ear consists of a labyrinth of fluid-filled chambers within temporal bone of
the skull. The labyrinth consists of two parts, i.e., the bony and membranous
labyrinth. The bony labyrinth is a series of channels.
Inside these
channels, membranous labyrinth lies, which is surrounded by a fluid called perilymph.
The membranous labyrinth is filled with a fluid called endolymph. The coiled
portion of the labyrinth is called cochlea.
The cochlea
has two large canals-an upper vestibular canal (scala vestibuli) and a lower tympanic
canal (scala typmani)-separated by a small cochlear duct (scala media). The vestibular
and tympanic canals contain perilymph and the cochlear duct is filled with endolymph.
At the base of scale
vestibuli, the wall of membranous labyrinth comes in contact with the fenestra
ovalis, while at the lower end of scala tympani lies the fenestra rotunda.
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