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Flashcards in Module D-11 Deck (65)
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1

What is sound?

pressure waves generated by mechanical vibrations

2

what are 3 characteristics of sound?

1) Frequency - perceived as a high or low tone or pitch
2) Intensity or amplitude- perceive as loudness
3) the point of origin - location

3

What is unit for the frequency of sound?

cycles per second ( cps) or Hertz ( Hz)

4

What is frequency range of sound audible to humans?

20 to about 20,000 Hz

5

What is sound intensity?

sound pressure levels (p) relative to the human auditory
threshold (p0) at 1000 Hz

6

Equation for sound intensity

Intensity (dB) = 20 log (p/p0)

7

unit for sound intensity

Decibels (dB)

8

What is the speed sound travels through air?

331 meter per second (m/s)

9

Describe pathway of sound into outer ear

The outer ear, filled with air, focuses sound into the external auditory meatus. Pressure waves generated by sound pass through the external auditory meatus
and produce vibrations of the tympanic membrane.

10

What separates the inner and outer ear?

Tympanic membrabe

11

What is the middle ear filled with?

air

12

How is the middle ear connected with the nasopharynx?

Eustachian ( pharyngotympanic ) tube

13

What are the ossicles of the ear?

malleus, incus and stapes

14

What are the 2 muscles of the inner ear?

m. tensor tympani and the m. stapedius

15

What is the function of the 2 muscles of the inner ear?

Contract To prevent damage to the inner ear during high intensity sound

16

The stapes vibrates the _______ window to produce vibratory waves of the inner ear

Oval

17

What is the bony compartment that contains the inner ear?

the Cochlea

18

Which compartments of the inner ear contain Perilymph?

scala vestibuli and scala tympani

19

Which compartments of the inner ear contain Endolymph?

scala media

20

The hair cells are located in the ___________ of the chochlea

Organ of corti

21

Where are the cell bodies of the afferents that receive the signal from the hair cells?

Spiral ganglion (form axons of auditory nerve CN VIII)

22

What are the 2 mechanisms of sound amplification in the middle ear?

1) Size difference of Tympanic membrane compared to oval window
2)Lever Ratio of the Ossicular Chain

23

How does the size difference cause pressure amplification of sound?

because the smaller the surface area the greater the pressure produced for the same force

24

How does the lever ratio of the ossicular chain cause pressure amplification?

Large movements (with little force) of the tympanic membrane are transformed into little movements (with greater force) at the oval window

25

By how much does the middle ear amplify pressure?

70-100 fold

26

Which ossicle is the tensor tympani muscle attached to ?

Malleus

27

Which ossicle is the stapedius muscle attached to ?

Stapes

28

Which nerve innervates the tensor tympani muscle?

Trigeminal nerve V

29

Which nerve innervates the Stapedius muscle?

Facial nerve VII

30

What happens when the 2 inner ear muscles are contracted

1) tensor tympani, limits the movement of the tympanic membrane;
2)stapedius, limits the movement of the stapedius