Physiology of the Auditory System

Question 1

Number of cycles per second (Name and Unit of Measurement)

Answer 1

Frequency * Hertz (Hz)

Question 2

Inverse of frequency, duration of a single cycle

Answer 2

Period

Question 3

Maximum amount of displacement from the null point in one direction

Answer 3

Amplitude

Question 4

Sound produced by simple harmonic motion

Answer 4

Pure tone

Question 5

T or F: Sound travels faster in air.

Answer 5

F * Dry Air: 340m/sec, Water: 1500m/sec

Question 6

Vibration that is not simple harmonic motion

Answer 6

Complex vibration

Question 7

Complex vibration with repetitive periodic pattern

Answer 7

Tone

Question 8

Complex vibration with no repetitivr pattern

Answer 8

Noise

Question 9

Amount of force that vibrating sound particles exert on a surface area (Name and measure)

Answer 9

Sound pressure * Pascals (Pa), also equals the square root of intensity

Question 10

Intensity is measured in____?

Answer 10

Decibels (dB)

Question 11

Frequency where stiffness and mass components of acoustic impedance cancel each other out

Answer 11

Resonance frequency

Question 12

Resonant frequency of 1) concha, 2) EAC

Answer 12

1) 5300 Hz, 2) 3000 Hz

Question 13

Sound coming from one side is attenuated by the head as it travels to the contralateral ear

Answer 13

Head shadow effect

Question 14

Important for low frequency sound localization

Answer 14

Interaural TIME difference

Question 15

Important for high frequency sound localization

Answer 15

Interaural AMPLITUDE difference

Question 16

Identify this pathway to sound transmission: sound goes to the inner ear in the absence of the ossicular system

Answer 16

Acoustic coupling

Question 17

Identify this pathway to sound transmission: Malleus is coupled to the TM. Vibration of the TM causes entire ossicular chain to vibrate. Sound is transmitted to the inner ear via the stapes footplate.

Answer 17

Ossicular coupling

Question 18

Name the 2 mobile joints of the ossicular chain and their types.

Answer 18

Incudomalleal, Incudostapedial * Synovial joints are also called Diarthrotic joints

Question 19

Difference between ossicular coupling and acoustic coupling in Db

Answer 19

60 dB * Maximal amount of hearing loss in ossicular diacontinuity

Question 20

This term denotes maximizing sound transfer

Answer 20

Impedance matching

Question 21

Most important factor in middle ear’s impedance matching capability

Answer 21

Area ratio (26 dB)

Question 22

Second mechanism for impedance matching due to the manubrium being slightly longer manubrium than long arm of incus - - a slight force on the manubrium (long arm of lever) results in a greater force in the long process of the incus (short arm of lever)

Answer 22

Lever ratio (2.3 dB)

Question 23

1) Theoretical 2) Actual middle ear sound pressure gain

Answer 23

1) 28dB, 2) 20dB * Actual gain is lower because the TM does not move as a rigid diaphragm, it vibrates in a complex manner. The effective area of TM involved with impedance matching is smaller than the total area

Question 24

Impediment to movement, ratio of acoustic pressure to the volume velocity generated by acoustic pressure

Answer 24

Impedance * Increased in fluid vs. Air

Question 25

Frequency where stiffness and mass components of acoustic impedance cancel each other out

Answer 25

System is in resonance

Question 26

Flask shaped, 3000 in number, arranged in a single row

Answer 26

Inner HC

Question 27

Cylindrical, 12000 in number, arranged in 3-4 rows

Answer 27

Outer HC

Question 28

This part is affected by movement of stapes on oval window (Scala?)

Answer 28

Vestibuli

Question 29

Basilar membrane is ____ stiff near the base and is more sensitive to _____ pitch

Answer 29

More, high

Question 30

Basilar membrane is ____ stiff near the apex and is more sensitive to _____ pitch

Answer 30

Less, lower

Question 31

This phenomenon involves shunting of acoustic energy away from the cochlea, leading to decreased sensitivity to AC sound and airbone gap seen on audiometry

Answer 31

Third window * Sup SCC syndrome, enlarged vestibular aqueduct, inner ear malformation

Question 32

Stereocilia deflected towards tallest row leads to

Answer 32

Depolarization

Question 33

Stereocilia deflected away tallest row leads to

Answer 33

Hyperpolarization

Question 34

OHC contracts during

Answer 34

Depolarization

Question 35

OHC elongates during

Answer 35

Hyperpolarization

Question 36

Also known as cochlear amplifier

Answer 36

OHC

Question 37

Bipolar, large, myelinated, 95%, synapses with SINGLE IHC

Answer 37

Type I spiral ganglion cells

Question 38

Smaller, un or myelinated, 5%, synapses with MULTIPLE OHC

Answer 38

Type II spiral ganglion cells

Question 39

High spontaneous neurons are best for these types of sounds

Answer 39

Low level sounds due to low threshold

Question 40

Low spontaneous neurons are best for these types of sounds

Answer 40

High level sounds due to their wide dynamic range

Question 41

First relay station for all ascending auditory information

Answer 41

Cochlear nucleus * In the pontomedullary junction

Question 42

Fiber tracts that project contralaterally to the inferior colliculus

Answer 42

Lateral lemniscus

Question 43

Relay station for binaural hearing

Answer 43

Superior Olivary Complex * Pons

Question 44

Area with important role in sound localization by determination of interaural time and amplitude difference

Answer 44

Superior Olivary Complex

Question 45

Ability to increase signal to noise ratio in binaural hearing

Answer 45

Binaural squelch

Question 46

Ability to receive sound signals in greater amplitude in binaural hearing

Answer 46

Summation

Question 47

Integrates information from auditory and nonauditory sources, also receives info on interaural time and amplitude differences, sends fibers to thr medial geniculate body of the thalamus

Answer 47

Inferior colliculus

Question 48

Involved in sound localization and processing of complex vocal communication

Answer 48

Medial geniculate body

Question 49

Division of the medial geniculate body that projects to the 1) primary 2) secondary auditory cortex

Answer 49

1) ventral 2) dorsal

Question 50

Broadmann area of 1) primary auditory cortex, 2) auditory association area, 3) Wernicke area

Answer 50

1) 41, 2) 42, 3) 22

Question 51

Speech _______: 1) Wernicke, 2) Broca

Answer 51

1) reception, 2) production

Question 52

Other areas of the brain receiving auditory information (2)

Answer 52

Amygdala, Limbic System

Question 53

Stapedius reflex pathway Cochlea to Stapes (7)

Answer 53

Cochlea, Cochlear Auditory nerve, Cochlear Nuclei, Stapedius Motoneurons, Facial Nerve, Stapedius, Posterior neck of stapes capitulum

Question 54

Primary sound evoked middle ear muscle

Answer 54

Stapedius * Tensor tympani plays a minor role

Question 55

Startle reaction is associated with this middle ear muscle

Answer 55

Tensor tympani

Question 56

1)Location, 2)Attachment, 3)Innervation of Tensor Tympani

Answer 56

Above ET, neck of manubrium, V3

Question 57

Olivocochlear pathway that innervates 1)OHC, 2) IHC

Answer 57

1)Medial Low freq sound, 2)Lateral high frequency sound (unclear role)

Question 58

This pathway decreases cochlear responses by decreasing the gain by hyperpolarization of the OHC (protect ears from acoustic trauma), also decreases auditory responses to the background noise

Answer 58

Medial Olivocochlear Complex Pathway