Lecture 14: Hearing

Question 1

causes of hearing loss

Answer 1

• Ageing
• Genetic
• Diseases
• -mumps & meningitis
• Noise
• Ototoxic drugs

Question 2

Hair cells job:

Answer 2

• Convert vibrations into nerve impulses

- dont regrow when damaged

Question 3

Organ of Corti:

Answer 3

• sensitive element in inner ear
• on basilar membrane of the cochlea
• 4 rows of hair cells
• tectoral membrane above hair cells
• -moves in response to to pressure changes in fluid filled canals

Question 4

Prevention of cell loss:

Answer 4

1) anti-oxidants
2) growth factors
3) Anti-apoptopic drugs
4) NMDA blockers

Question 5

Anti-oxidants (Ebselen)

Answer 5

• Synthetic
• Can decrease toxic function of SOD1 in ALS
• can prevent noise damage in cochlea
• Anti-ocidant levels decrease with age

Question 6

Growth Factors:

Answer 6

• Enhance vestibular hair cell renewal

- Results in improved vestibular function

Question 7

Anti-Apoptotic drugs:

Answer 7

• pathways promoting hair cell growth may be repressed

- Target repressors

Question 8

NMDA blockers:

Answer 8

Tinnitus induced by salicylate can be repressed by NMDA antagonists in cochlear fluids

Question 9

implantations:

Answer 9

1) Choclea implant (by-pass damaged hair cells)
2) Auditory nerve implant (by pass cochlea)
3) brain stem implant (by pass cochlea and auditory nerve)

Question 10

sensory regeneration:

Answer 10

• add antibodies against growth inhibitors

- add factors promoting regenerations

Question 11

insertion of bone marrow stem cells:

Answer 11

• tun to ear-like cells when exposed to chemicals produced by foetal cochlea
• mediated by int pathway

Question 12

neural human embryonic stem cells:

Answer 12

repair damage to auditory nerve

Question 13

retinoblastoma 1 deletion leads to

Answer 13

hair cell proflieration and then apoptosis

Question 14

Adult mouse utricle:

Answer 14

Stop signalling to notch 1, stop Hes inhibiting Atoh 1.

-Atoh 1 will be expressed and become hair cell