Senses 2- The Ear Flashcards
1
Q
What is sound?
A
A compressive wave with a velocity proportional to the density of the medium in which it travels
2
Q
What is the cochlea?
A
- The cochlea is a linear array of sensory ‘hair cells’ along the basilar membrane
- the basilar membrane resonates and mechanically amplifies sound with progressively lower frequencies along the length of the cochlea
3
Q
How many layer of hair cells are there?
A
4 - 3 outer 1 inner
4
Q
What is the consequence of losing hair cells?
A
- outer trouble hearing
- inner complete hearing loss
5
Q
What is conductive hearing loss?
A
- Blockage from wax or a ruptured eardrum- auditory canal
- Fluid accumulation (otitis media- ‘glue-ear’ -infection)
6
Q
What is sensory loss?
A
- Hair cells destruction in the cochlea (physical damage)
- Young- (listening to loud music- accumulates over a life-time)
- old- genetic susceptibility to hearing loss
7
Q
What is neural hearing loss?
A
- Spiral ganglion damage
- Tinnitus - phantom sound
- Alzheimer’s Disease is associated with hearing loss
8
Q
What happens in deafness?
A
- Sensory hair cells damaged and die
- Those at high frequencies are most sensitive- so you loose high frequencies first
- Hair cells cannot be replaced, so you lose hearing permanently
- So hearing loss accumulates with age and auditory insult
9
Q
How can deafness be treated?
A
Hearing aid
cochlea implant
hair cell regeneration
10
Q
What are the three broad types of genetic deafness?
A
- DFN- inherited x-linked
- DFNA- autosomal dominant
- DFNB- autosomal recessive
11
Q
What is the auditory pathway?
A
- Auditory cortex
- Medial Geniculate Nucleus
- Inferior Colliculus
- Superior Olivary Complex
- Cochlear Nucleus
- Spiral Ganglion cells
- Cochlea
