Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

neural circuits > auditory introduction > Flashcards

auditory introduction Flashcards

1
Q

Why is sound sensation important?

A

Early mammals were small and nocturnal
Triggers emotions
Communication, recognise different sounds, topographic view on auditory world
Survival

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is Tonotography?

A

relating to or being the anatomic organization by which specific sound frequencies are received by specific receptors in the inner ear with nerve impulses traveling along selected pathways to specific sites in the brain

in the cochlear - the base responds to high frequency , apex to low frequency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

how is Sound Frequency achieved and what the units

A

(Pitch) - Hz

  • A wide range of sound frequency has to be covered (x103).
  • Achieved by cochlear mechanics and physiology of hair cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

how is Sound Intensity (Loudness) achieved and what is it measured in

A

– dB

A huge range of sound intensity has to be encoded

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How does sound travel along the auditory pathway?

A

Sound enters ear, travels along the auditory canal hitting the tympanic membrane causing it to move backwards and forwards. This moves the ossicles of the middle ear causing the Oval window to move backwards and forwards causing fluid movement in the cochlear.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the three ossicles?

A

Malleus, incus and stapes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the function of the cochlea?

A

Contains sensory hair cells and nerve fibres that transmit the sound to the brain at a neuronal signal.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What does the cochlear consist of? and What are the three compartments inside the cochlear?

A

Three separate chambers which form the spiral of the cochlea travelling from the base to the apex.

Scala vestibuli – filled with perilymph, 0mV
Scala media – filled with endolymph, 80mV – active pumping from cells
Scala tympani – filled with perilymph, 0mV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe perilymph

A

Similar of ECF
Low potassium
Normal calcium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Describe endolymph

A

High potassium concentration – positive potential

Low calcium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Why does the Scala Media have a high K concentration and what does this create

A

because of active pumping from cells in the Scala vascularis.

creates a positive potential in this compartment compared to the Scala vestibuli and Scala tympani.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the endocochlear potential?

A

80 mV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the cochlear innervated by?

A

The auditory nerve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the organ of Corti? Where is it? what does it contain and its membrane potential?

A

The main sensory receptor – contains auditory receptors.

situated on the basilar membrane in one of the three compartments of the Cochlea.

It contains four rows of hair cells which protrude from its surface.

60 mV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the function of the inner hair cell of the cochlear?

A

The main sensory receptors of the cochlear

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the function of the outer hair cell of the cochlear? How many rows are there?

A

It’s the cochlear amplifiers

3 rows

17
Q

What are stereocilia?

A

Projections in the top of OHC and IHC and contact the tectorial membrane

18
Q

How has Tonotopicity been preserved?

A

A linear gradient of sound frequency is preserved in

19
Q

how does sound enter the cochlear and what does it create

A

Sound vibrations enter the cochlear as a pressure wave that travels along the diff compartments from the base of the cochlear to the apex – creating a wave along the basliar membrane that causes a maximal movement that corresponds to the freq of sound – called characteristic freq.

20
Q

what is the structure of the basilar membrane and how does this determine frequency

A

the width and stiffness of the basilar membrane – narrow and stiff at base and wider and more flexible at apex.

So high sound freq causes a peak movement towards base of the cochlear and lower freq cause a peak at the apex.

21
Q

How far does low frequency sound travel along the Basliar membrane and what does this cause?

A

The lower frequency sound travels further along the baslier membrane causing a peak towards apex of cochlear.

22
Q

How far does high frequency sound travel along the Basliar membrane and what does this cause?

A

The higher frequency sound doesn’t travel so far and causes a maximal movement towards the base.

23
Q

State the properties of the general hair cell found in auditory and vestibular system

A
  • Stereocilia hair bundle
  • Mechanoelectrical transducer channels (MET)
  • Voltage-gated Ca channels
  • Voltage-gated K channels
  • Nerve fibres
24
Q

How are all hair cells defined by? and How are the mechanoelectrical transducers channels connected to taller rows?

A

The stereocilia hair bundle that project from apical surface
MET located on tips of the shorter rows of stereocilia

connected By tip links

25
Q

what is the function of tip links?

A

When force is applied, they pull open the MET channels allowing current into the hair cell

26
Q

What does slight tension on tip links lead to?

A

Few are open leading to inwards resting transducer current carried by K ions - which depolarises inside of hair cell slightly giving it a more depolarised resting membrane potential.

27
Q

How is K able to enter the hair cell?

A

K able to enter cell down the electrical gradient due to the high K concentration in endolymph and difference in potential in between the Scala media and inside of the cell.

28
Q

What solution surrounds the apical surface of hair cells and stereocilia?

What solution surrounds the base of the hair cell?

A

What solution surrounds the apical surface of hair cells and stereocilia?
Endolymph

What solution surrounds the base of the hair cell?
Perilymph

29
Q

What does the slightly depolarised resting potential of general hair cells activate? What does this lead to? What is it called?

A

Activates some Ca channels and leads to a resting action potential firing rate in the nerve fibres called the spontaneous rate

30
Q

State the properties of an excitatory deflection of a general hair cell

A
  • Large deflection of the hair bundle
  • Maximal tip link tension
  • Large MET current
  • Fully depolarises hair cell
  • Rapid train of action potentials
31
Q

What does depolarisation of a general hair cell activate and what does this cause?

A

Depolarisation activates the Ca channels and increases neurotransmitter release and action potential frequency in the nerve fibre.
Also activates K channels that allow K ions out the cell – helps to repolarise the hair cell back to resting potential.

32
Q

State the properties of an inhibitory deflection of general hair cells

A
  • Large deflection of the hair bundle in opposite direction
  • Minimal tip link tension
  • No MET current
  • Fully hyperpolarises hair cell below resting potential

No or very few action potentials

33
Q

State properties of Outer hair cells (OHCs)

A
  • V-shaped hair bundle
  • Majority of nerves contacts are efferent fibres
  • Prestin in cell membrane required for electromotility

neural circuits (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions