Physiology of Hearing and Balance Flashcards

1
Q

What is sound?

A

a pressure wave caused by oscillating molecules which are set in motion by a vibration

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

What does frequency dictate?

A

pitch

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

what does amplitude dictate?

A

intensity

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

What is the function of the middle ear?

A

amplifier

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

Why does the middle ear need to amplify sound?

A

Because there is a change from air sound waves to fluid waves. With this change there is a loss of energy, so the middle ear acts to minimise this change in energy between impendances

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

How does the middle ear amplify sound?

A

The ear drum is about 20 times bigger than the oval window, so the sound pressure in air is concentrated through the ossicles into the small oval window, increasing the sound pressure, the lever action- differences in lengths of the piston of the stapes and handle of malleus also does this

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

What muscles open the eustachian tube?

A

tensor veli palatini and levator palatine

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

What is the function fo the eustachian tube?

A

to equalise the ears

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

What type of fluid is the endolymph like compared to the perilymph?

A

endolymph is like ICF whereas perilymph is like ECF

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

What is the purpose of endolymph?

A

it helps support the hair cells by being high in potassium

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

What is the purpose of the inner hair cells?

A

sound perception

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

What is the purpose of the outer hair cells?

A

regulate and modulate sound that foes in- dont perceive soudn

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

What is transduction?

A

conversion of mechanical bending force into electrical impulse

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

How are the stereocilia arranged?

A

in height order with tip links connecting them together

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

What happens when the stereocilia move?

A

gap junctions are opened which let ions in and depolarise/hyperpolarise creating an AP

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

How is depolarisation of the cilia created?

A

when the cilia are deflected towards the longest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

when does hyperpolarisation of the cilia happen?

A

when deflected away from the longest

18
Q

What is the tonotopic organisation of the cochlea?

A

the basilar membrane is continuously graded in order to respond to different frequencies of sound

19
Q

What frequency of sound is received at the base?

A

high frequency

20
Q

What frequency of sound is received at the apex?

A

low frequency

21
Q

What is the mnemonic for the central pathway of hearing?

A
E- eighth nerve
C-cochlear nucleus
O - superior Olivary complex
L-lateral meniscus
I-inferior colliculus
22
Q

Where is the inferior colliculus found?

A

superior temporal gyrus

23
Q

What are hte 3 things that contribute to balance?

A

ears; eyes; proprioception

24
Q

What are the maculae of the utricle and saccule?

A

otolith organs

25
Q

What are the 2 functions of the otolith organs?

A

sense linear acceleration (movement in a straight line) and sense the heads position in gravity

26
Q

What is found in the membrane of the otolith organs?

A

otoconia- calcium carbonate crystals

27
Q

What is the purpose of the otoconia?

A

give the gel extra mass and gravity pulls on the cystals so when the gravitional pull changes because the head has moved, they sense this.

28
Q

How do the hair cells in the otolith organs detect movement?

A

they bend which opens the gap junctions and lets in potassium which depolarises the cell

29
Q

How do the otolith organs detect movemnent in all planes?

A

the hair cells are orientated in all directions

30
Q

What type of motion does the saccule detect?

A

vertical plane

31
Q

What type of motion does the utricle detect?

A

horizontal plane

32
Q

What is the push-pull orientation?

A

The semi-circular canals are paired to one on the other side of the head which means that when one canals hair cell potential is increased, the other is decreased

33
Q

What is the cupula?

A

a membrane in the ampulla which the sterocilia project into

34
Q

What is the purpose of the vesitbulo-ocular reflex?

A

stabilise the retinal image during the rotation of the head

35
Q

What type of movement does the posterior canal detect?

A

head tilt to the left or right (tilting head to touch shoulder)

36
Q

What type of movement does the superior canal detect?

A

front to back- nodding

37
Q

What type of movement does the horizontal canal detect?

A

shaking of head

38
Q

What is the vestibulospinal tract?

A

motor output to neck, back and leg muscles

39
Q

What is the purpose of the pathway of medial lemniscus and thalamus to cerebrum

A

some central control/override

40
Q

What is the medial longitudinal fasciculus and ocular muscle pathway for?

A

motor output to eyes

41
Q

How are hair cells organised in the utricle compared to the saccule in relation to the matrix?

A

saccule- are arranged away from the matrix; in the utricle are arranged towards the matrix