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HEARING AND
EQUILIBRIUM
DONE BY: SANAZ & OMAR
THE EAR
• The ear is the sensory organ responsible for
hearing and equilibrium.
• The ear is divided into 3 main
sections: outer ear, middle ear, and inner
ear.
1. The outer ear
2. The middle ear
3. The inner ear
OUTER EAR
• Extends from the outside of the head to the eardrum.
• Responsible for drawing in radiations to be translated to sound.
• External ear.
• Consists of: Auricle, ear canal (auditory canal), ear lobe, hairs (some cases)
• Air-filled cavity that contains the three auditory
ossicles or ear bones.
• Starts from the ear drum and extends to the
third ossicle.
• Contains: Tympanic membrane, ear drum,
Malleus (hammer), anvil (incus),
stirrups (stapes)
MIDDLE EAR
INNER EAR
• The inner ear is protected by the hardest bone in the
body.
• The cochlea is a bony tube that contains fluids as well
as neurons that move in response to the vibrations of
the fluids.
• The movement generates neural impulses that are
transmitted to the brain via the auditory nerve.
• Within the brain, auditory input is projected onto the
hearing areas of the cerebral cortex
• Vibrations of the stapes against the oval window
produce pressure waves in the perilymph of the
cochlea.
THE SENSE OF HEARING
• The ear converts vibrations in the air into electrical signals that our brains perceive as
sounds.
1. Outer ear: collects sound waves to eardrum
Parts: Pinna, auditory canal
2. Eardrum: thin, cone-shaped membrane that separates outer and middle ear
3. Middle ear: air filled cavity of the ear; behind the eardrum
Parts: eardrum, hammer, anvil, stirrup, oval window
4. Inner ear: home of the cochlea, the actual hearing organ and semicircular canals responsible for balance
Parts: semicircular canals, cochlea, nerve receptors, auditory nerve
DAMAGE TO THE MIDDLE EAR
• Conductive deafness
• Injury, infection, or tumors.
• Treated by: medications or surgery.
DAMAGE TO THE INNER EAR
• Sensorial deafness
• Injury, trauma, infection, tumors.
• Treatment: surgery (cochlear transplant) or hearing aid.
SEMICIRCULAR CANALS
• Three canals are horizontal, superior and
posterior semicircular canals.
• Is a part of the vestibular system.
• Balance in movement of head in telling the
position.