Physiology of Hearing Flashcards Preview

Theme 2: Sensory Inputs and Motor Outputs > Physiology of Hearing > Flashcards

Flashcards in Physiology of Hearing Deck (26)
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1
Q

What is the membrane between the scala vestibuli and scala media?

A

reissner’s membrane

2
Q

What is the membrane between the scala tympani and scala media?

A

basilar membrane

3
Q

The scala vestibuli is associated with what structure in the inner ear?

A

oval window

4
Q

The scala tympani is associated with what structure in the inner ear?

A

round window

5
Q

OTITIS MEDIA

A

Infection or inflammation of middle ear
Usually self-limiting

Common in children
Often from upper respiratory tract infection

Secretory form with effusion
“Glue ear”
If chronic causes a conductive hearing loss
May need draining
Grommets
6
Q

OTOSCLEROSIS

  • cause
  • treatment
A
  • Fusion of stapes with oval window

- Can be fixed by surgery

7
Q

Cochlear Nucleus (CN)

A

– parallel processing starts here

  • Auditory nerve fibres from cochlear ganglion innervate many types of neuron
  • Neurons extract information about level, onset and timing of sounds
8
Q

Superior Olivary Complex (SOC)

A

– uses inter-aural time differences and inter-aural intensity differences for localization

  • Interaural level differences are detected in the lateral superior olive (LSO)
  • Interaural time differences are detected in the medial superior olive (MSO)
9
Q

Inferior Colliculus (IC)

A
  • layers
  • combines spatial analysis from SOC with information from dorsal CN, and directs auditory reflexes

-encodes complexity and localization of sound
Auditory reflex centre; reflexive orientation to stimuli

10
Q

Auditory Cortex (AC)

A

many functions including the analysis of complex sounds (eg speech) and sound localization

11
Q

Outline the central auditory system

A
Cochlear nucleus
Then project ipsilaterally and contralaterally to SOC 
Nuclei of lateral leminiscus 
Inferior colliculus 
Medial geniculate body 
primary auditory cortex
12
Q

What does the Medial Superior Olivary complex respond to?

A

responds to arrival time differences

i.e interaural time differences

13
Q

What does the lateral Superior Olivary complex respond to?

A

responds to amplitude differences

i.e interaural level differences

14
Q

Where is the inner ear located?

A

in the petrous part of the temporal bone

15
Q

What type of innervation do inner hair cells receive?

A

afferent innervation

16
Q

What type of innervation do outer hair cells receive?

What are their main functions

A

efferent innervation

-amplify basilar membrane motion

17
Q

What kind of fluid of fluid is contained within scala vestibuli and scala tympani?
Describe this fluid

A

perilymph

high in Na+
low in K+

18
Q

What kind of fluid of fluid is contained within scala media?

Describe this fluid

A

endolymph

low in Na+
high in K+

19
Q

What is the function of hair cells in organ of corti?

A

move with the movement of the fluid and the stereocilia set up an action potential within the cochlear nerve

20
Q

Describe the mechanism of mechanotransduction in hair cells

A

movement of hair buncle opens non-selective cation channels

  • K+ enters
  • depolarisation
  • Ca2+ enters
  • triggers vesicle release
  • Afferent nerver fibres activated
21
Q

What type of cells are inner hair cells

A

sensory

22
Q

What types of cells are outer hair cells

A

sensori-motor

23
Q

Afferent innervation of the cochlear

A

Inner hair cells innervated by type 1 spiral neurons

outer hair cells innervated by type II spiral neurons

24
Q

Efferent innervation to the cochlear

A

efferent fibres from medial olive innervate outer hair cells directly

efferent fibres from lateral olive synapse on Type 1 afferent
-Activation of efferent system modifies the sensitivity of the cochlea

25
Q

Conductive Hearing Loss

A

sound can’t pass from outer or inner ear to the cochlea

26
Q

Sensorineural Deafness

A

due to a fault in the inner ear or the cochlear nerve