Zusammenfassung der Ressource
Hard hearing
- External ear
- Collects sound waves and
channel them down the
auditory channel
- Vibration of the
tympanic membrane
- Middle ear
- Auditory ossicles
- Malleus
- Sound waves
traveling through
air must be
converted into
pressure waves
in fluid.
- When the sound waves move the tympanic membrane, the chain
of ossicles also moves, pushing the footplate of the stapes into
the oval window and displaces the fluid in the cochlea
- Incus
- Stapes
- Inner ear
- Sensory
organ
- Cochlea
- 3 coiled tubes
- Scala vestibuli
- Contains
perilymph
- Scala media
- Contains
endolymph
- Scala tympani
- Contains perilymph
- Reissner's membrane
- Basilar
membrane
- Organ of Corti
lies on it
- Inner hair
cells
- Outer hair
cells
- Helicotrema
- Point of
communication
between the
scala vestibuli
and scala
tympani. Scala
media does
not
communicate
with these
two scala.
- Tympanic
membrane
- Separates
external ear
from internal
ear
- Pearly gray and
translucent, with a
sharp light reflex
and bony landmarks
- Hearing loss
- Conductive
hearing loss
- sound waves are not
adequately conducted through
the external or middle ear
- Cause: Damage to cochlea, CN VIII
or central auditory connections.
- Air conduction> bone conduction
- Sensorineural hearing loss
- Sound waves are not translated into
nerve signals and not recognized as sound
sensations by the brain.
- Etiology: physical blockade
of the ear canal
- Bone conduction> air
conduction
- Presbycusis
- partial loss of hearing as a
result of loss of hair cells
- Caused due to
aging
- Infections of the
ear
- Otitis externa
- Inflammation
of the external
ear
- Acute loxalized
otitis externa
- Furunculitis
which leads to
furuncle
formation
- Staphylococcus
aureus
- Acute diffuse
otitis externa
- Swimmer's ear
- Most
common
form
- Pseudomonas
aeruginosa
- Otitis media
- Inflammation of
the middle ear
- Acute otitis media
- Causative agent
- Streptococcus
pneumonia
- Haemophilus
influenza
- Moraxella
catarahlis
- Complication
- Cholesteatoma
formation
- Tympanic membrane retraction
- Lead to pocket that protrudes
into the middle ear
- dead skin cells accumulate
in pocket
- Acute otitis media
with effusion
- Chronic otitis media