Ch 3 - Auditory Flashcards
(51 cards)
1
Q
Sound is measured in
A
Decibels (dB)
2
Q
Sound frequency is measured in
A
Hertz (Hz)
3
Q
Greatest Sensitivity to sound frequency is
A
between 2000 & 5000 Hz
4
Q
Able to discriminate between the intensity of
A
1 dB & 2 dB
5
Q
Range of sound frequency
A
20 Hz - 20,000 Hz
6
Q
Human speech range frequency
A
300 Hz - 3000 Hz
7
Q
As one ages we have a decrease in
A
High frequency tone
8
Q
Sound is understood by which CN?
A
CN VIII
9
Q
Components of Outer Ear
A
- Auricle/pinna
- External auditory meatus
10
Q
Function of Outer Ear
A
Collection of sound waves & conduction to tympanic membrane
11
Q
Components of Middle Ear
A
- Tympanic Membrane
- Middle ear ossicles: Malleus, Incus, & Stapes
- Tensor tympani & stapedius muscles
12
Q
Tensor tympani is innervated by
A
Trigeminal Nerve
13
Q
Stapedius muscle is innerved by
A
CN VII Facial Nerve
14
Q
Function of Tensor tympani & Stapedius muscle
A
Dampen sound
15
Q
Functions of Middle Ear
A
Sound amplifier
16
Q
The Middle Ear communicates w/ nasopharynx via
A
Auditory tube
17
Q
Middle Ear cavity is innervated by
A
CN 9 (Glossopharyngeal Nerve)
18
Q
Pathology of middle ear cavity results in
A
Conduction Hearing Loss
19
Q
Function of Inner Ear
A
Sound transduction
20
Q
Components of Inner Ear
A
- Cochlear & organ of Corti
- Semicircular canals
• lateral
• posterior
• superior
21
Q
Perilymph
A
- Similar to ECF
- The fluid within vestibuli & tympani
- High sodium, low potassium concentrations
22
Q
Endolymph
A
- Similar to ICF
- The fluid within media
- High potassium, low sodium
23
Q
Similar to ICF, this fluid is found within media
A
Endolymph
24
Q
Similar to ECF, this fluid is found within vestibule & tympani
A
Perilymph
25
Perilymph or Endolymph: Which contains high sodium & low potassium concentrations?
Perilymph
26
Perilymph or Endolymph: Which contains high potassium & low sodium concentrations?
Endolymph
27
The cochlea is
The sensory apparatus of transduction. It contains the organ of corti
28
Separates vestibuli & media
Reissner's membrane
29
Separates media & tympani
Basilar membrane
30
Organ of corgi lies on ____ within the _______ and is surrounded by _____
Organ of corti lies on basilar membrane within the scala media and is surrounded by endolymph
31
Auditory receptors are innervated by
CN VIII (Vestibulocochlear Nerve)
32
Inner hair cells are arranged
In single rows
33
Outer hair cells are arranged
In parallel rows; greater quantity
34
Bending of the cilia hair cells in one direction results in increased K+ conduction (______) and decreased K+ conduction (______) in the other direction
Depolarization & Repolarization
35
Depolarization of the cilia hair cells
Opens Ca2+ channels in the presynaptic terminal of hair cells releasing excitatory NT increasing the firing of CN VIII (Vestibulocochlear)
36
Hyperpolarization of the cili hair cells
Decreases the release of excitatory NT w/ resultant intermittent firing of CN VIII (Vestibulocochlear)
37
Mechanism of Auditory Transduction Starting from Sound Waves, Ending in APs in afferent cochlear nerves
Sound Waves -> Vibration of organ of Corti -> Bending of cilia on hair cells -> Change in K+ conductance of hair cell membrane -> Oscillating receptor potential (cochlear microphonic) -> Intermittent glutamate release -> Intermittent APs in afferent cochlear nerves
38
Mechanical deformation of stereocilia toward the kinocilium causes
K+ channels to open in the stereocilia, leading to depolarization, leading to Ca2+ to enter the cell, allowing vesicle fusion & the release of NT
39
Mechanical deformation of stereocilia away from the kinocilium causes
The K+ channels to close and Hyperpolarization or Repolarization occurs
40
Base of Basilar Membrane
- towards the oval window
- narrow and stiff
- Responds best to HIGH FREQUENCIES
41
Apex of Basilar Membrane
- towards helicotrema
- wide and compliant
- Responds best to LOW FREQUENCIES
42
Function of the Vestibular System
- Equilibrium or balance
| - Works in conduction w/ the visual system
43
Semicircular Canals
- Arranged perpendicularly to each other
- Detects angular/rotational acceleration of the head
- Ampulla at end of each canal contains the sensory receptor
44
Gelatinous mass
Cupula
45
During Horizontal Rotation what happens?
You have horizontal angular acceleration which is sensed by lateral semicircular canal. When head moves horizontally, the endolymph moves in the opposite direction (b/c cupula moves faster than the endolymph) pushing the stereocilia towards the kinocilium ipsilaterally causing depolarization (excitation) and away from the kinocilium contralaterally (hyperpolarization = inhibition). When the endolymph catches up, the cilia will return to their original position, hence point of neither depolarization or hyperpolarization. When the movement stops, the opposite occurs. This excitatory or inhibition is then sent via CN VIII to the CNS.
46
Otolith Organs
Sensitive to linear acceleration/deceleration of the head due to gravitational forces
Composed of Utricle & Saccule
47
Utricle
Sensitive to forward-backward movements
48
Saccule
```
Sensitive to movements in all directions
Sensitive to:
- backward-forward movement
- lateral displacements
- up-down
- most sensitive to lateral displacement
```
49
Nystagmus
- Occurs in response to angular or rotational acceleration of the head
- Head rotates and eyes initially move in the opposite direction of the rotation in an attempt to maintain a constant gaze = slow component of nystagmus
- When the eyes reach their maximum lateral stretch, there is a rapid return to align w/ the head as it turns = rapid component of nystagmus
- IT IS DEFINED BY THE DIRECTION OF THE RAPID COMPONENT
50
Postrotatory Nystagmus
If the rotation is stopped abruptly, the eyes will move in the direction opposite that of the original rotation. During the postrotatory period, the person tends to fall in the direction of the original rotation (due to stimulation of contralateral extensor muscles) b/c the person "thinks" he or she is spinning in the opposite direction
51
Caloric Test
Pour cold water in ear & Nystagmus to opposite side of treated ear
Pour warm water in ear & Nystagmus to same side of treated ear
Remember Acronym COWS
It is an indication that brain stem is intact
