7. HEARING Flashcards
1
Q
- What is sound?
(in physics terms)
A
- a vibration that typically propagates as an audible wave of pressure
- this happens through a transmission medium
(such as: a gas, liquid or solid)
2
Q
- What happens when we talk?
A
- our vocal folds vibrate
3
Q
- What happens when we slap the top of a table or play guitar, what happens?
A
- the air particles vibrate
- this initiates sound waves
- these carry vibrations through the air
4
Q
- What do sounds generated from different mediums lead to?
A
- they lead to different sounds
- this is because different vibrating objects produce differently shaped sound waves
5
Q
- What is a sound frequency?
A
- it is the number of waves that pass a certain point at a given time
6
Q
- What is a high-pitched noise a result of?
A
- shorter waves that are moving in and out more quickly
7
Q
- What is a lower pitch a result of?
A
- slower fluctuations
8
Q
- What does the loudness of a sound depend on?
A
- it depends on the wave’s amplitude
- the amplitude is the difference between the high and the low pressures created in the air
- they are created in the air by sound waves
9
Q
- What is sound in the terms of human psychology and physiology?
A
- it is the reception of sound waves
- and the perception of these by the brain
10
Q
- Between which frequencies can human beings hear?
A
- between 20 Hz and 20 kHz
- everything under 20 Hz is infrasound
- everything over 20 kHz is ultrasound
11
Q
- What is the unit of measurement for the intensity of sound?
A
- decibels (dB)
12
Q
- How does the decibel scale work?
A
- it is logarithmic
- an increase of 10 decibels means that the sound is ten times louder
13
Q
- Sound above what decibel can cause hearing loss?
A
- any sound above 85dB
- hearing loss is related to both power of sound
AND length of exposure
14
Q
- Sounds above which decibel cause immediate damage and actual pain?
A
- sounds above 140 dB
15
Q
- What are the three parts that make up the human ear?
A
- outer ear
- middle ear
- inner ear
16
Q
- What does the outer ear consist of?
A
- the pinna
17
Q
- What is the function of the pinna?
A
- it protects the delicate inner parts of the ear
- it protects the external auditory meatus
(this is the air canal that collects sounds and directs it
towards the ear drum)
18
Q
- How is the shape of the pinna beneficial?
A
- it helps it to detect where sounds are coming from in the
vertical plane - this helps to identify whether sounds are coming from above or below the ear
19
Q
- What is the middle ear?
A
- it is an air filled cavity
20
Q
- Where is the middle ear located?
A
- it is located in the temporal area of the skull
21
Q
- What does the middle ear consist of?
A
- the ear drum
- the tympanic membrane
- the ossicles
- the eustachian tube
22
Q
- What shape is the tympanic membrane?
A
- it is concave
23
Q
- What is the tympanic membrane?
A
- it is an area between 60mm-90mm
- it has an average thickness of a 700s of a millimetre
- it has a very rich blood supply
24
Q
- What do the sound waves do to the tympanic membrane when they enter the ear canal?
A
- they strike the tympanic membrane
- they set it into motion
25
Q
- What determines how much the tympanic membrane will move?
A
- the loudness of the sound
- the louder the sound
- the more the tympanic membrane moves
26
Q
- What does the middle ear contain with regards to bone structure?
A
- it contains three small bones
- these are known as the ossicles
- they are connected in a chain across the middle ear
- they are connected from the tympanic membrane to the entrance of the cochlea
27
Q
- What is the biological term for the entrance of the cochlea?
A
- the oval window
28
Q
- What are the names of the ossicles?
A
- the malleus (hammer)
(the largest) - the incus (anvil)
(the second largest) - the stapes (stirrup)
(the smallest)
29
Q
- What does the tympanic membrane do in response to the sound?
A
- it vibrates
30
Q
- What happens in response to the vibration of the tympanic membrane?
A
- the ear drum moves the malleus
- this then moves the incus
- the stapes is then finally moved
- this then moves the foot plate in and out of the oval window
31
Q
- What is the result of the foot plate moving in and out of the oval window?
A
- there is an energy transfer
- this energy is transferred to the endolymph fluid in the cochlea
32
Q
- What are the two distinct portions of the inner ear?
A
- the vestibular portion
- the auditory portion
(the cochlea)
33
Q
- What is the focus of the vestibular portion?
A
- it is concerned with balance
34
Q
- What is the function of the auditory portion?
A
- it is concerned with hearing
35
Q
- What is the vestibular portion of the inner ear made up of?
A
- it is made up of three semicircular canals
36
Q
- What does each semicircular canal consist of?
A
- it has a swelling on the one end
- it has two membranous sacks
37
Q
- What is the biological name of the following:
37.1: the swelling of the semicircular canal
37.2: the two membranous sacks of the semicircular canal
A
37.1: the ampulla
37.2: the utricle
: the saccule
38
Q
- What do the utricle, the saccule and the ampulla all contain?
What is the function of these components?
A
- they contain fluid
- they contain sensory cells
- they move in response to the head movement
- they travel to indicate the body’s status
39
Q
- With which organ and cells does the vestibular system work in conjunction (in connection) with?
What does the result in?
A
- the eyes
- the receptor cells in the joints of the body
- this continuously maintains our balance
40
Q
- What physical form does the cochlea appear in?
A
- it appears as a coiled tube
- it is in the shape of a snail shell
41
Q
- What is the cochlea wrapped around?
A
- it is wrapped around the acoustic portion of the auditory nerve
42
Q
- What is the cochlea split into?
A
- three distinct sections
43
Q
- Name the three distinct sections that the cochlea is split into?
A
- the scala vestibuli
- the scala media
- the scala tympani
44
Q
- What type of fluid do the scala vestibuli and the scala tympani contain?
A
- perilymph fluid
45
Q
- What type of fluid does the scala media contain?
A
- endolymph fluid
46
Q
- What separates the scala vestibuli from the scala media?
A
- the Reissner’s Membrane
47
Q
- What separates the scala media from the scala tympani?
A
- the Basilar Membrane
48
Q
- What can be found along the basilar membrane?
A
- two types of sensory cells/hair cells
49
Q
- What are the two types of sensory/hair cells called?
A
- outer hair cells
- inner hair cells
50
Q
- How are these sensory/hair cells arranged along the basilar membrane?
A
- they are arranged in rows
- this is done according to their frequency
OR the pitch of sound they detect
51
Q
- What does each hair cell have?
What are these called?
A
- it has tiny hair like projections attached to it
- these are called stereocilia
52
Q
- What happens when sound energy is transferred to the cochlea?
A
- the basilar membrane vibrates up and down
- this causes the outer hair cells stereocilia to sheer
(SHEER: swerve, change course) - they sheer on the tectorial membrane above them
53
Q
- What does the sheering action result in?
A
- it results in the stereocilia bending
- this opens the ion gates
- this leads to chemical changes
- it results in the electrical charge inside the cells
54
Q
- What do the electrical charges inside the cell do?
A
- they make neural impulses
- these travel along the auditory nerve to the brain
- this is interpreted as sound
