AUDITORY
SYSTEM
Hearing is one of the major sense which is important for
communication. Organ of hearing have three parts which is Outer ear, Middle ear
and Inner ear.
Outer ear: Outer ear is divided into two parts first one is Pinna which is protrudes from one side
of the skull made of cartilage made of skin. Pinna is also known as Auricle. Pinna
is helpful in localising environmental sounds. External Auditory Canal: EAC is also known as ear canal which is
about 4 cm long. The outer portion of EAC is lined with hairy skin containing
sweat gland and oily sebaceous gland which together form wax.
Middle Ear: The middle ear is an air filled cavity connected to the back of
the nose by a thin tube called Eustachian tube. There are three bones in middle
ear, Mallecus, Incus and Stapes. Middle ear is starts from TM (Tympanic
Membrane) or Ear Drum. Ear drum is smooth, translucent and almost transparent
membrane which is about 0.074mm thick. Three tiny bones which is also known as
ossicles or the ossicular change which transmitted the sound induced vibration
of tympanic membrane to the cochlea via oval window. The ossicles are the
smallest bones of the body. The functions of middle ear are conduction of sound
from outer ear to inner ear. Middle ear muscle also provide protection from
loud sounds. Convert acosustic energy to mechanical. The acosustic energy is in
air would be transmitted to the inner ear fluid.
Inner ear have different parts i.e. Cochlea, Semi circular Canal
and Vestibule.
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