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Flashcards in Audition Deck (39):
1

What are some important functions for hearing

1. Communication
2. Detect danger
3. Help

2

What is sound

Variations in air pressure

3

What is the difference between the speed of sound through air vs. through water

air 767mph (340m/s)

water 1500m/s

4

What is a sounds wave

Alternating peeks and valleys of compressed air

5

What are the variables in sound?

Frequency (pitch)

Intensity (loudness)

6

What is the definition of frequency

The number of comprised air patches (Hertz)
-number of cycles/second

7

What is the definition of Intensity

The difference in pressure between compressed air patches
-amplitude

8

What is the human frequency range

20-20,000

9

In which frequency range are we most sensitive to

2,000-4,000
which is speech range

10

What is the difference between Hertz and Decibel

Hertz measured the pitch
Decible measures the loudness

11

What is the minimum audibility curve

The minimum frequencies that are at a level for us to hear

12

What are the 3 major divisions of the ear

1. Outer Ear
-Auricle (Pinna)
-Auditory canal

2. Middle Ear
-Tympanic membrane
-Ossicles

3. Inner Ear
-Oval window
-Cochlea

13

What is the function of the auditory canal

To protect the ear drum
Enhances the intensities of sound by resonance

14

What is the definition of resonance

A mechanism that enhances the intensity of certain frequencies because of the reflection of sound waves in a closed tube
-amplifies frequency depending on length and width of tube

15

What are the 3 Ossicles

1. Malleus (hammer)
2. Incus (anvil)
3. Stapes (stirrup)

16

What is the Eustachian (auditory) tube

An airway between the middle ear and the pharynx
-allows you to change the pressure in your ear

17

What are the 3 reasons why the Ossicles necessary

1. Sound vibration is ineffective at moving fluid
2. Ossicles amplify the force exerted against the oval window
3. Ossicles convert air pressure changes to mechanical changes (causing fluid changes win the cochlea)

18

What are the two windows of the cochlea

The oval window (in contact with stapes)

Round window

19

What are the 3 ducts of the cochlea

1. Vestibular duct (separated by resigners membrane)
2. Cochlear duct (separated by basilar membrane)
3. Tympanic duct

20

What are the 2 different fluids in the 3 chambers

1. Perilymph (Vestibular and tympanic duct, flows into each other)
2. Endolymph (Cochlear duct)

21

Why is the basilar membrane important?

Contains the Organ of Croti

22

What hangs over the organ of corti

The tectoral membrane

23

What is the Helicotrema

A hole between the scala vestibule and scala tympani
(at the very end of the unrolled cochlea)

24

How does sound move through the cochlea

Oval window> Scala Vestibuli> Helicotrema> Scala Tympani> Round Window

25

What is the base of the basilar membrane

The base is thin and the membrane is thick
-high frequencies are encoded

26

What is the apex of the basilar membrane

The apex is wide and the membrane is less rigid
-low frequencies are encoded

27

What is the organ of corti

Lies on the basilar membrane and contains hair cells
The movement of the hair cess changes the activity of the hair cell

28

What is the hair cell

Cells in the organ of corti in which when moved, the hair cells depolarize when the stereocilia bend

Tips of the stereocilia are in contact with the sectoral membrane.

29

What are the 2 types of hair cells

Inner hair cells

Outer hair cells

30

What are inner hair cells

Auditory receptor cells in the inner ear that are primarily responsible for auditory transduction and the perception of pitch
-only 5000 per ear

31

What are outer hair cells

Auditory receptor cells in the inner ear that amplify the response of the inner hair cells
-more numerous

32

What is motile response and how does it work

A response to sound of the outer hair cells in which the cells move

Cells tilt and get slightly longer, amplifies the basilar membrane vibration and amplify the response of the inner air cells

33

How do signals get out of the cochlea

Hair cells synapse with spiral ganglion cells
-the axons of these neurons form the auditory portion of the Vestibulocochlear Nerve (cranial nerve 8)

34

In which place in the brain does the sound from both ears come together

The Superior olives

35

Where is the primary auditory cortex

On the superior temporal gyrus

36

What kind of map is in the auditory cortex

Tonotopic map
-based on frequency lengths, shortest in the front and longer towards the back

37

Why doesn't the destruction of the auditory cortex in one hemisphere result in loss of hearing on one side

Because input from both ears goes to each hemisphere

38

What does the destruction of the auditory cortex result in

A loss of the ability to localize sound in the opposite hemifield

39

What is most hearing loss due to

Death or destruction of hair cells
-cant regenerate