CH 16 Ears

Question 1

Structure + Function of Ears

Answer 1

• sensory organ for hearing and maintaining equilibrium
• external ear (auricle/pinna)
  
  • funnels sound waves
  • produces cerumen for protection
• middle ear
  
  • auditory ossicles (bones)
  • eustachian tube (allows passage of air/connect middle ear with nasopharynx)
  • functions
    
    • conduct sound vibrations from outer ear
    • protect inner ear by reducing loud sounds
    • allows equalization of air pressure

Question 2

Hearing (3 levels)

Answer 2

Peripheral - sound waves come in/ear transmits and converts to electrical impulses (mechanical)

Brainstem - locate/identify sound AND differentiate time and intensity (sending of the message)
- CN VIII (vestibulocochlear)

Cerebral Cortex - interpret the meaning of the sound

Question 3

Pathways of Hearing

Answer 3

• air conduction is normal and most efficient

- bone conduction (vibrations) is alternate route

Question 4

Hearing Loss

Answer 4

Conductive (blockage of sound waves)

• mechanical dysfunction of middle/external ear
• EX. impacted cerumen, foreign body, perforated TM

Sensorineural

• pathology of inner ear
• EX. ototoxic drugs or Prebycusis (age-related nerve degeneration)

Mixed (combo of both)

Question 5

Developmental Considerations

Answer 5

Infant/Children
- shorter/wider eustachian tube = higher risk for middle ear infection

Adults
- otosclerosis: conductive hearing loss between 20-40 y/o

Aging Adults

• cilia become coarse and stiff
• Prebycusis (lose ability to hear higher frequencies over time)

Question 6

Collecting Objective Data: Ears (inspect auricles)

Answer 6

• size/shape/symmetry
• landmarks (tip of ear in line with eyes)
• skin (lesions? nodules)
• palpate for tenderness

Question 7

Collecting Objective Data: Ears (inspect external auditory canal)

Answer 7

check for drainage and odor

Question 8

Collecting Objective Data: Ears (inspection with otoscope)

Answer 8

External ear canal: patency (open, unobstructed), color, drainage, lesions, foreign object

Tympanic Membrane: color (shiny/translucent), integrity (intact)

Question 9

Collecting Objective Data: Ears (hearing test)

Answer 9

Audiometric: most accurate
- test ability to hear multiple frequencies

Whispering test
- test ability to hear high-tones