6: Physiology - Sensory transduction: auditory and vestibular system Flashcards Preview

Neurology Week 2 2018/19 > 6: Physiology - Sensory transduction: auditory and vestibular system > Flashcards

Flashcards in 6: Physiology - Sensory transduction: auditory and vestibular system Deck (45)
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1

Which cells, found in the inner ear, convert sound energy (moving them) into action potentials?

Hair cells (stereocilia)

2

Hair cells are connected to ___ ___ neurons.

special sensory

3

What excites stereocilia?

Movement by sound energy

4

Which channels are found at the tips of stereocilia?

What enters when they are open?

Tip links

K+ (which ENTERS unusually and depolarises the membrane)

5

When stereocilia are excited by movement and the opening of tip link channels, the sensory neurons connected to them are EXCITED.

Which neurotransmitter is released to cause an excitatory action potential?

Glutamate

6

Hair cells are found throughout the labyrinth of the inner ear, which is responsible for hearing and balance.

The function of hair cells changes based on their ___ in the labyrinth.

position

7

What properties of a sound wave match to

a) pitch

b) volume?

a) Frequency

b) Amplitude

8

Why do vibrations received by the tympanic membrane need to be amplified before they pass into the cochlea?

It takes more energy to vibrate fluid compared to air

9

Which bones are mostly responsible for amplifying the vibrations received by the tympanic membrane?

Ossicles

10

Which chamber in the Organ of Corti contains the hair cells?

Scala media

11

Which membrane do hair cells sit on in the Organ of Corti?

Basilar membrane

12

What properties of the basilar membrane allow to discriminate between sounds of different pitches?

Oval window end (the base) is wide and flexible

Apex is narrow and stiff

So different energy levels i.e pitches of sound are required to move the hair cells depending on what end you're at

13

Which membranes are found 

a) superior to

b) inferior to

hair cells in the Organ of Corti?

a) Tectorial / Reissner's membrane

b) Basilar membrane

14

The basilar membrane changes the ___ of hair cells by bending in response to sound energy.

The tectorial membrane actively ___ hair cells by vibrating.

basilar membrane changes hair cell position

tectorial membrane moves hair cells by vibrating

15

The potassium concentration of the fluid surrounding hair cells (?endolymph) is (high / low).

high Kconcentration

16

In which direction does potassium move when the tip links of hair cells are open?

Why?

Inwards

K+ concentration in endolymph is high

17

Which fluid is found in the scala media?

Endolymph

18

Which fluid is found in the scala vestibuli and scala tympani?

Perilymph

19

What happens to the potassium which enters hair cells through tip links?

After action potential K+ is recycled back into scala media to keep conc. gradient the same

20

How are hair cells arranged in the Organ of Corti?

Outer layer

Inner layer

21

Which layer of hair cells is concerned primarily with sensory input?

Inner layer

22

Which nerve carries the sensory neurons from the inner hair cells?

Cochlear part of CN VIII

23

Each inner hair cell is supplied by (a single / many) sensory neuron(s).

each inner hair cell has its own sensory neuron

24

What is the primary function of outer hair cells?

Movement of the tectorial membrane to enhance vibration

25

How many outer hair cells are connected to each somatic efferent fibre?

Many

26

Where do sensory neurons synapse between the inner hair cells and CN VIII?

Spiral ganglion

27

superior olivary ganglion somatic efferents outer hair cells

28

sensory coding of pitch depends on firing rate of hair cells AND where they are on the basilar strip

29

On which side of the brain are auditory signals processed?

Both

processing is bilateral

30

Briefly describe how auditory stimuli reach the primary auditory cortex from the inner ear.

CN VIII fibres > Spiral ganglion > Cochlear nucleus > Superior olivary nucleus > Inferior colliculus > Medial geniculate nucleus > Primary auditory cortex

sorry