Page 339 - Color Atlas Of Pathophysiology (S Silbernagl Et Al, Thieme 2000)

A. Conductive Hearing Loss
Purulent middle Normal
ear infection 60 250 1000 4000 Hz
–20
Foramen dB Bone conduction
Lesion ovale 0
of the ossicles
20 Air
conduction
60 250 1000 4000 Hz
–20
dB
Foramen 0
rotundum
20
Middle ear 40 Hearing Impairment
Tear in eardrum
60
Conductive hearing loss

B. Inner Ear Hearing Loss
1 Tectorial Plate 10.16
Sound, ischemia, toxins membrane
–20 60 250 1000 4000Hz
Outer dB Bone conduction
Inner 0
hair cells 20
Basilar Air
conduction
membrane 40
Age 60
Basilar membrane 4
stiffness Inner ear hearing loss
3 Genetic defect
Loop of K channel Disorder of
+
diuretics endolymph 6
Disorder of 2Cl – Deafness absorption
endolymph Endolymph
secretion K + K + edema
Na + s.B1
K +
Na + Scala vestibuli Increased
K + K + (perilymph) 7 permeability
Na + Na + Deafness
100
Level of sound pressure (dB SPL) 80 Normal 5 Scala media K + Scala tympani Menière’s disease
Hearing loss
Vertigo
(endolymph)
60
40
6 10 20 30 2 (perilymph)
Frequency (kHz) 329

Silbernagl/Lang, Color Atlas of Pathophysiology © 2000 Thieme
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