1. transduction , AUDITORY PATHOLOGY , AND AUDITORY PERCEPTION
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

2. BY : NUR AZMINA MOHD ZAILAN NUR FARHANA OTHMAN
Mechanism of sound
transduction
BY : NUR AZMINA MOHD ZAILAN NUR FARHANA OTHMAN

5. HOW THE EAR HEARS ? SOUND BRAIN AURICLE AUDITORY OSSICLES (M, I, S )
TYMPANIC MEMBRANE
VESTIBULAR WINDOW
(OVAL WINDOW)
PERILYMPH
AUDITORY
OSSICLES
(M, I, S )
SCALA
VESTIBULI
COCHLEA
(ORGAN OF CORTI )
BRAIN

6. 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.

7. 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 

8. 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.

9. 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. 

10. Auditory Pathology

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

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

13. 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.

14. 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.

15. 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.

16. MIXED:
both conductive and sensorineural
OTHER CONDITIONS
Central auditory processing disorders (CAPD)
-primarily CNS problems, but may involve sensorineural hearing loss
Presbycusis

17. Conductive

18. Otitis Externa Infections of the ear canal
Caused by bacteria, virus or fungus cultivated in the external ear canal.

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

20. Sensorineural

21. Damaged Hair Cells

22. Tumor in Vestibulocochlear nerve

23. 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

24. Approximate Range (Hz)
Species
Approximate 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
100-40,000
Ferret
16-44,000 
Opossum
500-64,000 
Chinchilla
90-22,800 
Bat
2, ,000 
Whale
1, ,000
Elephant
16-12,000 
Example of the range of hearing in different species