Disorders of the ear
- sensorineural hearing loss
- conductive hearing loss
Disorders of the eye
- hyperopia
- myopia
Myopia definition
distant objects are blurry while nearby objects are clear
Myopia causes
- elongated eyeball
- inability for the lens to become thin enough
Technologies used to correct Myopia
- concave lens which spreads out the input of light before it enters the eye’s convex lens
Hyperopia definition
distant objects are clear yet close objects are blurry
Hyperopia causes
- shortened length of eyeball
- lens cannot become round enough
Technologies used to correct hyperopia
- laser eye surgery to adjust the curvature of the cornea
- convex lenses to converge light rays as they enter the eye’s convex lens
Conductive hearing loss definition
blockage or damage within the auditory ear canal resulting in a loss of loudness
Conductive hearing loss causes
- blockage such as earwax or a foreign object
- trauma or damage to the ear drum such as by a pencil
Sensorineural hearing loss definition
damage to the cochlea hairs within the inner ear resulting in loss of loudness or lack of clarity
Sensorineural hearing loss causes
- ageing prsocess
- excessive noise exposure
- disease
Technologies for hearing loss
- hearing aid
- cochlea implant
What is a hearing aid
An electronic device that amplifies sound entering the external ear
–> can help people who have conductive hearing loss or mild sensorineural hearing loss
Process of a hearing aid
Microphone - detects sound and converts it into an electrical signal
Amplifier - magnifies the strength of the sound
Receiver - turns electrical signals back into sound waves
Speaker - projects sound into middle ear
Benefits of a hearing aid
- relatively cheap
- no surgery required
- can restore some hearing
Limitations of a hearing aid
- does not restore full sound
- all parts of the ear must be fully functioning to some extent
What is a cochlea implant
the ‘bionic ear’ sends electrical pulses to the auditory nerve to help treat severe to profound hearing loss
–> due to damage to cochlea hairs
Process of a cochlea implant
Processor - detects sound and converts it into digital code
Implant - turns digital code into electrical impulses
Electrode - is implanted in cochlea and transmits the electrical impulses to the auditory nerve
Benefits of cochlea implant
- can facilitate hearing in profoundly deaf people
Limitations of cochlea implant
- very expensive
- requires surgery
- does not work if damage is to auditory nerve
- must be trained to interpret sound
Function of the kidney
- to maintain fluid balance
- regulating and filtering minerals in the blood
- removal of nitrogenous waste (urea)
Disorder of the kidney
Kidney failure (chronic or acute)
–> unable to balance water and salt in the body and remove waste is life threatening
Kidney transplant
–> preferred method
Benefits
- prolongs life
- no restrictions on intake
Limitations
- long waiting list
- rejection
- immunosuppressants
