Presentation on theme: "transduction , AUDITORY PATHOLOGY , AND AUDITORY PERCEPTION"— Presentation transcript:
1 transduction , AUDITORY PATHOLOGY , AND AUDITORY PERCEPTION Mechanism of soundtransduction , AUDITORY PATHOLOGY , AND AUDITORY PERCEPTIONBY : 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 soundtransductionBY : NUR AZMINA MOHD ZAILAN NUR FARHANA OTHMAN
5 HOW THE EAR HEARS ? SOUND BRAIN AURICLE AUDITORY OSSICLES (M, I, S ) TYMPANIC MEMBRANEVESTIBULAR WINDOW(OVAL WINDOW)PERILYMPHAUDITORYOSSICLES(M, I, S )SCALAVESTIBULICOCHLEA(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 cortiThe 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.
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 defectsInfectionsTraumaVascular DisordersAging DisordersTumor
13 Developmental defectPotential 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.InfectionsCommon cause of outer and middle ear disorder.Caused by bacteria, virus or fungus.Can result in significant sensorineural hearing loss.TraumaPhysical and acousticPhysical- Ossicular disruption, fracture of temporal bone.Acoustic- Due to excessive noise.
14 Vascular disorderInterruption 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 disorderPresbyacusis- 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 sensorineuralOTHER CONDITIONSCentral auditory processing disorders (CAPD)-primarily CNS problems, but may involve sensorineural hearing lossPresbycusis
23 Auditory PerceptionThe ability to perceive and understand sounds with a specific organ; earsNo auditory perception is inability to hear = deafnessDifferent species have different range of hearing – dogs can hear high pitched sound that human can’t hear
24 Approximate Range (Hz) SpeciesApproximate Range (Hz) Human20-20,000Dog67-45,000 Cat45-64,000 Cow23-35,000 Horse55-33,500 Sheep100-30,000 Rabbit360-42,000 Rat200-76,000 Mouse1,000-91,000 Gerbil100-60,000 Guinea pig54-50,000 Hedgehog250-45,000 Raccoon100-40,000Ferret16-44,000 Opossum500-64,000 Chinchilla90-22,800 Bat2, ,000 Whale1, ,000Elephant16-12,000 Example of the range of hearing in different species