24
BY : NUR AZMINA MOHD ZAILAN NUR FARHANA OTHMAN NUR ZULAIKHA MAT ZAWAWI NUR NABILA ROZAINI NUR ATHIRAH MOHD AZHAR Mechanism of sound transduction , AUDITORY PATHOLOGY , AND AUDITORY PERCEPTION

Mechanism of sound transduction, AUDITORY PATHOLOGY, AND AUDITORY PERCEPTION

Embed Size (px)

Citation preview

Page 1: Mechanism of sound transduction, AUDITORY PATHOLOGY, AND AUDITORY PERCEPTION

BY : NUR AZMINA MOHD ZAILAN NUR FARHANA OTHMAN NUR ZULAIKHA MAT ZAWAWI NUR NABILA ROZAINI NUR ATHIRAH MOHD AZHAR

Mechanism of sound transduction , AUDITORY PATHOLOGY , AND AUDITORY

PERCEPTION

Page 2: Mechanism of sound transduction, AUDITORY PATHOLOGY, AND AUDITORY PERCEPTION

BY : NUR AZMINA MOHD ZAILAN NUR FARHANA OTHMAN

Mechanism of sound transduction

Page 3: Mechanism of sound transduction, AUDITORY PATHOLOGY, AND AUDITORY PERCEPTION
Page 4: Mechanism of sound transduction, AUDITORY PATHOLOGY, AND AUDITORY PERCEPTION
Page 5: Mechanism of sound transduction, AUDITORY PATHOLOGY, AND AUDITORY PERCEPTION

HOW THE EAR HEARS ?

SOUND AURICLE

TYMPANIC MEMBRAN

E

AUDITORY

OSSICLES

(M, I, S )

VESTIBULAR WINDOW

(OVAL WINDOW)

PERILYMPH

SCALA VESTIBULI

COCHLEA(ORGAN

OF CORTI )

BRAIN

Page 6: Mechanism of sound transduction, AUDITORY PATHOLOGY, AND AUDITORY PERCEPTION

COCHLEA

Long coiled tube Three channels The top tube is the scala vestibuli, which is

connected to the oval window. The bottom tube is the scala tympani, which is connected to the round window. The middle tube is the scala media, which contains the Organ of Corti. The Organ of Corti sits on the basilar membrane, which forms the division between the scalae media and tympani.

Page 7: Mechanism of sound transduction, AUDITORY PATHOLOGY, AND AUDITORY PERCEPTION

high frequency sounds stimulate the base of the cochlea, whereas low frequency sounds stimulate the apex.

Sound waves cause the oval and round windows at the base of the cochlea to move in opposite directions 

 causes the basilar membrane to be displaced and starts a traveling wave that sweeps from the base toward the apex of the cochlea 

Page 8: Mechanism of sound transduction, AUDITORY PATHOLOGY, AND AUDITORY PERCEPTION

Organ of corti

The traveling wave causes the Organ of Corti to move up and down.

The tectorial membrane to move laterally over the hair cells. This motion bends the cilia and opens the trap-door channels . The influx of potassium and then calcium causes neurotransmitter release. Most of the afferent dendrites make synaptic contacts with the inner hair cells.

Page 9: Mechanism of sound transduction, AUDITORY PATHOLOGY, AND AUDITORY PERCEPTION

Most of the afferent dendrites synapse on inner hair cells.

Most of efferent axons synapse on the outer hair cells.

The outer hair cells are active. They move in response to sound

and amplify the traveling wave. 

Page 10: Mechanism of sound transduction, AUDITORY PATHOLOGY, AND AUDITORY PERCEPTION

Auditory Pathology

Page 11: Mechanism of sound transduction, AUDITORY PATHOLOGY, AND AUDITORY PERCEPTION

Definition

Auditory Pathology:-The cause and effect of diseases relating to the sense of hearing.

Page 12: Mechanism of sound transduction, AUDITORY PATHOLOGY, AND AUDITORY PERCEPTION

There are several major categories that can affect the auditory system:- Developmental defects Infections Trauma Vascular Disorders Aging Disorders Tumor

Page 13: Mechanism of sound transduction, AUDITORY PATHOLOGY, AND AUDITORY PERCEPTION

Developmental defect Potential development defects are numerous, and

many of them are inherited. Many inherited disorders result in congenital

hearing loss; others result in progressive hearing loss later in life.

Infections Common cause of outer and middle ear disorder. Caused by bacteria, virus or fungus. Can result in significant sensorineural hearing loss.

Trauma Physical and acoustic Physical- Ossicular disruption, fracture of temporal

bone. Acoustic- Due to excessive noise.

Page 14: Mechanism of sound transduction, AUDITORY PATHOLOGY, AND AUDITORY PERCEPTION

Vascular disorder Interruption of blood supply to the

cochlea can cause a loss of hair cell function which result in permanent hearing loss.

Causes of blood supply interruption- stroke, diabetes mellitus.

Aging disorder Presbyacusis- a decline in hearing as

a part of aging process.

Page 15: Mechanism of sound transduction, AUDITORY PATHOLOGY, AND AUDITORY PERCEPTION

Types of Hearing Loss

Critical Fact types:CONDUCTIVE: processes that prevent sound from reaching

the cochlea. It caused by problems in the external ear (often when the ear canal is blocked, by wax for example), or the middle ear (otitis, glue ear, damaged ossicles,…).

SENSORINEURAL: processes that damage hair cells, spiral

ganglion cells (and/or the auditory nerve) or cochlear nucleus neurons.

Page 16: Mechanism of sound transduction, AUDITORY PATHOLOGY, AND AUDITORY PERCEPTION

MIXED: both conductive and sensorineural

OTHER CONDITIONS Central auditory processing disorders (CAPD)

-primarily CNS problems, but may involve sensorineural hearing loss Presbycusis

Page 17: Mechanism of sound transduction, AUDITORY PATHOLOGY, AND AUDITORY PERCEPTION

Conductive

Page 18: Mechanism of sound transduction, AUDITORY PATHOLOGY, AND AUDITORY PERCEPTION

Otitis Externa Infections of the ear canal Caused by bacteria, virus or fungus

cultivated in the external ear canal.

Page 19: Mechanism of sound transduction, AUDITORY PATHOLOGY, AND AUDITORY PERCEPTION

Otitis Media Inflammation of middle ear. Caused primarily by Eustachian tube

dysfunction.

Page 20: Mechanism of sound transduction, AUDITORY PATHOLOGY, AND AUDITORY PERCEPTION

Sensorineural

Page 21: Mechanism of sound transduction, AUDITORY PATHOLOGY, AND AUDITORY PERCEPTION

Damaged Hair Cells

Page 22: Mechanism of sound transduction, AUDITORY PATHOLOGY, AND AUDITORY PERCEPTION

Tumor in Vestibulocochlear nerve

Page 23: Mechanism of sound transduction, AUDITORY PATHOLOGY, AND AUDITORY PERCEPTION

Auditory Perception

The ability to perceive and understand sounds with a specific organ; ears No auditory perception is inability to hear = deafness Different species have different range of hearing – dogs can hear high pitched sound that human can’t hear

Page 24: Mechanism of sound transduction, AUDITORY PATHOLOGY, AND AUDITORY PERCEPTION

SpeciesApproximate Range

(Hz) Human 20-20,000

Dog 67-45,000 Cat 45-64,000 Cow 23-35,000 

Horse 55-33,500 Sheep 100-30,000 Rabbit 360-42,000 

Rat 200-76,000 Mouse 1,000-91,000 Gerbil 100-60,000 

Guinea pig 54-50,000 

Hedgehog 250-45,000 

Raccoon 100-40,000Ferret 16-44,000 

Opossum 500-64,000 Chinchilla 90-22,800 

Bat 2,000-110,000 

Whale 1,000-123,000

Elephant 16-12,000 

Example of the range of hearing in different species