WAVES (PART 5) Flashcards
1
Q
- Where does air need to cause vibrations?
A
- air needs to cause vibrations
- these need to be produced in the larynx
- this is where the vocal chords and folds are
2
Q
- What are Vocal Chords?
A
- they are the bands of muscular tissue
- they have variable and controlled dimensions
- they have tension and elasticity
3
Q
- What is the space between the Vocal cords called?
A
- the Glottis
4
Q
- What makes the the vocal cords oscillate easily?
A
- the flexible structure of the vocal cords
5
Q
- What is the main organ in the process of Speech Perception?
A
- the ear
6
Q
- Which 3 parts does the ear consist of?
A
- the outer ear
- the middle ear
- the inner ear
7
Q
- What does the outer ear consist of?
A
- it is made up of three parts:
1. Pinna
2. Ear Canal
3. Eardrum
(Tympanic Membrane)
8
Q
- What is the Pinna?
A
- the flesh part we see on the sides of our heads
9
Q
- What happens when the sounds waves travel to the Pinna and the Canal?
A
- the sound waves are channelled
- they are slightly modified by the pinna and the canal
- these waves cause the tympanic membrane to vibrate
10
Q
- What is the main function of the outer ear?
A
- it catches sound waves
- this is accomplished by the Pinna
11
Q
- What is the direction of the Pinna?
A
- the Pinna is pointed forward
- it has a number of curves
- this allows it to be able to catch the sound and
determine its direction
12
Q
- What happens after the sound reaches the Pinna?
A
- it is guided to the middle ear
- this is through the use of the external auditory canal
- this is until it reaches the eardrum
13
Q
- Which structure is found in the Middle Ear?
A
- a series of small bones
- these are suspended by ligaments
- these are known as Ossicles
14
Q
- Where exactly are the Ossicles found?
A
- they sit in a bony enclosure
- this is connected to the Oral Cavity by the Eustachian
Tube
15
Q
- Which of the Ossicles connected to the Tympanic Membrane?
A
- the Malleus
16
Q
- What does the Malleus connect to?
A
- it connects to the Incus
- this in turn connects to the Stapes
- the Stapes is connected to the Oval Window
NB:
the movement of the ossicles causes the movement in the fluid inside the cochlea
17
Q
- What is the Main Function of the Middle Ear?
A
- it is there to magnify the sound pressure
NB:
- this is because the inner ear transfers sound through
fluid and not air
- the middle and the outer ear transfer sound through
air
18
Q
- What does the Inner Ear start with?
A
- the inner ear starts with the Cochlea
- this is a cavity that is encased in bone
- it is filled with a fluid
- the cochlea is coiled up like a snake shell
- it has a length of 3.5m when it is stretched out
19
Q
- What is the Cochlea divided into?
A
- the Cochlea is internally divided into two halves by a
membrane
20
Q
- On which membrane are sound waves turned into signals?
A
- the Basilar Membrane
21
Q
- What does the Cochlea perform?
A
- Spectral Analysis of the Speech signal
22
Q
- What is the Input Stimulus split into?
A
- it is split into several frequency bands
- these are all called Critical Bands
23
Q
- What happens in each critical band?
A
- the ear averages the energies of the frequencies within
each critical band - this forms a compressed representation of the original
stimulus
24
Q
- What are the four steps in the Hearing Process within the ear?
A
- the sound wave enters the outer ear
- the movement of the tympanic membrane is
transferred by conduction
. it is transferred through the Ossicles to the oval
window of the cochlea - the movement of the oval window generates a
compressional (sound) wave
. it generates the wave in the fluid of the Cochlea - the sound wave moves the Basilar Membrane
. the primary auditory receptors (the hair cells are
located on this membrane
. the hair cells generate electrical signals
. these are sent to the brain
25
Q
- From which points do the Normal-human Auditory system sensitivity start from?
A
- they start from about 20 Hz
- they go up to 20 kHz
26
Q
- What frequencies is the ear most sensitive to?
A
- it is most sensitive to frequencies between 100 Hz and
4000 Hz
27
Q
- Which sound levels are considered harmful?
A
- sound levels about 85 dB
28
Q
- Which sound levels are considered unsafe?
A
- any sounds above the pain threshold
- this threshold is 120 dB
- these are unsafe
29
Q
- What sound levels cause physical damage to the human body?
A
- sounds above 150 dB cause physical damage to the
human body
30
Q
- What do safety organisations do to avoid hearing damage?
A
- they recommend exposure to no more than 85-90 dB
for 8 hours a day - 100 dB for 2 hours a day
- 110 dB for 30 minutes a day
31
Q
- At which dB can eardrums rupture?
A
- the eardrums rupture at 190 dB to 198 dB
- sound levels around 200 dB can cause death to
humans
32
Q
- What is the main way that hearing loss is evaluated?
A
- by determining the Threshold for hearing pure tones from about 125-8000 Hz
33
Q
- What is the Hearing Threshold (HL) usually expressed as?
A
- it is expressed as the threshold value of hearing
- it is expressed in dB HL versus audio frequency
34
Q
- What happens to the the threshold expressed in dB HL at each frequency?
A
- the threshold in dB HL is expressed in dB minus
- dB minus is the reference normal value in dB
35
Q
- What is normal hearing defined as?
A
- it is defined as 0 dB at all levels that are considered audible
36
Q
- What are the dB parameters for people who are said to have normal hearing?
A
- a dB HL of less than and equal to 15
- these are people who are considered to have an average frequency response
37
Q
- What is hearing loss defined as?
A
SLIGHT HEARING LOSS:
- average value of 16-25 dB HL
MILD HEARING LOSS:
- average value of 26-40 dB HL
MODERATE HEARING LOSS:
- average value of 41-55 dB HL
MODERATELY SEVERE HEARING LOSS:
- average value of 56-70 dB HL
SEVERE HEARING LOSS:
- average value of 71-90 dB HL
PROFOUND HEARING LOSS:
- greater than 90 dB HL
38
Q
- How would this graph be read?
A
- it would be left from left to right
