ear

Question 1

ear

Answer 1

-composed of 3 sections

Question 2

external ear (pinna, auricle)

Answer 2

• shape maintained by cartilage

- shape serves to funnel sound down the external auditory meatus-sound funneled down canal toward middle ear

Question 3

middle ear

Answer 3

• outer barrier: tympanic membrane, eardrum
• sound waves strike eardrum causing it to oscillate
• vibrations passes in to auditory ossicles(malleus, incus, stapes/hammer, anvil, stirrup) transmit vibrations to oval window of inner ear
• eustachian tube connects middle ear to nasal passage to regulate air pressure in ear

Question 4

inner ear

Answer 4

• 2 purposes
• mechanical vibrations from auditory ossicles are encoded into electrical impulses for interpretation by brain
• vibrations passed along cochlea(contains fine hair cells that encode)
• semicircular canals: fluid filled, assist w/balance
• as head is tilted from upright, fluid moves w/feedback being transmitted to brain

Question 5

auricular hematoma

Answer 5

• cause: blow to ear(causes shear stress), cauliflower ear
• perichondrium(covering of cartilage of ear) pulls away from cartilage, causing bleeding/localized collection of blood
• if left untreated, blood is irritating t cartilage causes overgrow(heaped up cartilage)
• can cause permanent cosmetic injury&decrease efficiency of sound funneling down ear canal

Question 6

external otitis (swimmers ear)

Answer 6

• skin infection of external auditory meatus
• usually bacterial
• itching, pain, occasional discharge
• pulling down on pinna is painful

Question 7

otitis media

Answer 7

• middle ear infection
• very common in children
• bacterial infection w/excess fluid collection in middle ear
• tympanic membrane red, bulging

Question 8

ruptured eardrum

Answer 8

-cause: change in pressure, blow to ear, excessive fluid build up