sensory organ for hearing and maintaining equilibrium
The shape is to encourage sound waves into ear opening.
Canal is 2.5-3cm long
end at ear drum
Contains ceruminous glands which secrete Cerumen/earwax
which lubricates and protects ear canal and stops debris entering.
- consists of:
- AuricleExternal acoustic meatus and lateral surface of the
- Tympanic membrane
Function is to conduct soundwaves to the tympanic membrane
- air-filled cavity containin three tiny bones:
- Functions of middle ear include:
- 1. conducts sound vibration from outer ear to central hearing in inner ear.
- 2. protects inner ear
structure of the the ossicles is arranged to transmit sounds from one to another and finally to the oval windown and into the fluid-filled inner ear.
Connects the middle ear with the nasopharynx.
Normally closed but opens with yarning or swallowing
Provide equal air pressure on both sides of the tympanic membrane to ensure that sound transmission is stabilised and avoid ruptured of the tympanic membrane during air travel.
Also aviods ruptured of tympanic membrane during air travel.
Contains a system of inteconnecting membranous channels
that is divided into:
- semi-circular canals
- each filled with a fluid call endolymph
Channels are separated from the surrounding boney structure by fluid called perilymph
*The receptor organ of hearing where transduction of sound stumuli occurs
*Specifically in the organ of corti which is located in the cochlea
*Transduction then travels via afferent fibres via the auditory nerve to the brain
Pathway of hearing
- 1. Sound waves enter the external ear, passing through the ear canal.
- 2. Sound waves reach the tympanic membrane causing it to vibrate.
- 3. The vibration travel through the ear ossicles and enters the inner ear
- 4. The vibration cause tiny hair cells in the cochlea to move and converted into electrical impulses.
- 5. electrical impulses is sent to the hearing nerve fibers and to the brain as sound.
Hearing loss or hearing impaired.
- conductive hearing loss caused by mechanical dysfunction of the outer or middle ear.
- >Partial loss of hearing
- >auditory nerve is normal
- Sensorineural hearing loss
- >Dysfunction with the inner ear and/or cranial nerve or the auditory area of the cerebral cortex
loss is the combination of both.
- *helps people with severe sensorineural hearing loss or nerve deafness.
- *2 parts: internal called cochlea implant
- exteral called speech processor
- *Speech processor uses 2 small microphones to pick up sounds
- *It turns sounds into signals & sends them to a transmitter
- *transmitter sends the signal through the skin to the inernal implant.
- *signal is then converted into electral energy and sends to electrode array.
- *nerve fiber in the cochlea is stimulated and the signals is send to the brain and recongized as sound.
Vestibular system ( control balance)
- *Responsible for balance and located in inner ear
- *Senses head motion and acceleration
- *maintains and assists recovery of a stable body and head position
*disorders can result from motion sickness an distension of endolymphatic area of inner ear.
infant's eustachian tube
- more horizontal positioning
this creats an easier pathway for pathogens from nasopharynx to migrate to middle ear.
- *Cillia lines ear canal becomes corses and stiff and obstruct sound waves.
- *Impacted drier cerumen causes hearing loss
*Presbycusis-gradual sesnsorineural hearing loss in aging adult caused by nerve degeneration 50+
*After 70 years or older auditory reaction time to process sesnroy input and respond.
Nursing history data for ear assessment:
Helps to identify patient's risks of hearing disorders.
- *Has patient expericencing pain, itching, discharge, tinnus or change in hearing?
- *Is patient using hearing aid?
- *Rcent hearing loss?
- *family history of hearing loss?
- *exposure to lound noises at workplace, any protective device used for it?
- *has patient experience repeated history of cerumen builup in ear
An ear infection (acute otitis media) is most often a bacterial or viral infection that affects the middle ear. Children are more likely than adults to get ear infections.
The build-up of thick fluid in the middle ear causing temporary hearing loss. This condition is very common in young children
Otoscope is used to observe the deeper structures of the external and middle ear.
Otoscope is a special ear speculum attached to an ophthalmoscope.
To avoid damaged to the ear canal, patient must remain still during the examination
- *Perform conventional assessment including ticking watch, whiper test, and tuning fork.
- *Perform audiometry
- *observe client conversation with others
- *inspect ear canal for hardened cerumen.
- *Assess client's perception of hearing avility and history of tinnitus.
Children behaviour that indicate hearing deficit
- *Frightened when unfamiliar people approach
- *no response or reflex to sounds.
- *failure to be woken up by loud noises
- *avoid social interaction with other children
- *slow or absent development to sound
Adults behaviour changes that indicate hearing deficit
- *blank looks
- *lack of reaction to loud noises
- *speaks loudly
- *positioning head towards sound
- *use other types of communication method such as lipreading or writing
- *complaints of ringing ears.
What parts of ear does otoscope examine?
Ear canal and tympanic membrane
Describe the structure of tympanic membrane
Shiny and translucent, prominent care of light reflects
Describe the landmark of they tympanic membrane
- cone of light
- handle of malleus
Name the gland that secretes cerumen (ear wax)?
What is the earwax function?
Protect ear canal and stops debris entering
Sometimes noise seem far away but is heard during yawning and swallowing, why is that?
This is associated with the pressures in the middle ears. Yawning and swallowing change the pressure in the ear due to the movement of earwax.
How does mallus, anvil and stapes transmit vibrations?
The three tiny bones are arranged in such a way to transmit sound vibrations from one to the next and finally to the oval window and then into the fluid filled inner ear.