Monday, 4-11-Hearing & Vestibular Senses Physiology (Karius)

Question 1

The scala vestibuli and scala tympani are continuous, fluid-filled compartments (helicotrema connection) and the fluid inside is ___

The fluid inside the scala media is __

Answer 1

Perilymph

Endolymph

Question 2

Perilymph is most similar to ___

Answer 2

ECF–> High Na, low K

Question 3

Which membranes create the scala media to isolate it from perilymph?

Answer 3

Basilar and Reissner’s membranes

Question 4

What is the electrolyte contents of the endolymph (fluid in scala media)?

Answer 4

High K, low Na–> most similar to ICF

Question 5

The composition of the __ will have a significant effect on the transduction of sound waves into AP’s

Answer 5

Endolymph

Question 6

The middle ear transmits the sound waves from the air environment of middle ear to the aqueous environment of the __. The ossicles transmit and amplify the sound waves from the tympanic membrane to the __ of the cochlea

Answer 6

Cochlea

Oval window

Question 7

__ sounds cause the maximum vibration of the basilar membrane CLOSEST to the oval window. I.e., the sound of a picollo

Answer 7

High frequency, short wavelength

Question 8

___ sounds cause the maximum vibration of the basilar membrane farthest away from the oval window (toward the helicotrema), i,e., a tuba sound

Answer 8

Low frequency, long wavelength

Question 9

Each hair cell is composed of a distinct arrangement of shorter stereocilia that increase in length. Each stereocilia is connected to another at the top by an extracellular filamentous protein which is known as the __

Answer 9

Tip link

Question 10

During development, there is a single true cilium known as the ___. It is the tallest of the ‘hairs’ on the hair cell.

Answer 10

Kinocilium

Question 11

How do hair cells bend?

Answer 11

When sound causes the basilar membrane to vibrate, the connections between the basilar membrane and the tectorial membrane cause the tectorial membrane to move as well

Question 12

During transduction, if the stereocilia are bent towards the kinocilium, the hair cell ___

Answer 12

Depolarizes

Question 13

During transduction, if the stereocilia move away from the kinocilium, the hair cell ___

Answer 13

Hyperpolarizes

Question 14

Bending the hair cells toward the kinocilium opens __ channels that depolarize the cell

Answer 14

K+

-Due to the composition of the endolymph (high K+, low Na+), K+ enters the hair cells and causes it to depolarize. Ca2+ is also involved

Question 15

In auditory processing in the cochlear nucleus, the __ path starts processing of temporal and spectral features of the sound, i.e., timing and pitch

Answer 15

Ventral

Question 16

In auditory processing in the cochlear nucleus, the __ path integrates the acoustic information with somatosensory information for localizing the sound, i.e., tells you where the sound came from

Answer 16

Dorsal

Question 17

The __ generates a map of the intraaural time differences (how the sound arrived at the 2 ears differently). I.e., when a dog barks closest your right ear, the sound will reach the right ear microseconds before it reaches the left ear. This area is located in the pons.

Answer 17

Medial superior olive

Question 18

The ___ generates a map of the intra-aural intensity differences (how the sound arrived at the 2 ears differently). I.e., when a dog barks closest to the right ear…because the left ear is farther away from the source of the sound, the intensity (amplitude) of the sound is slightly reduced compared to what the right ear detected. This area is located in the pons

Answer 18

Lateral superior olive

Question 19

The __ (located in the midbrain) suppresses information related to echoes (they interfere with location) and arrives at a final estimation of the sound location on the horizon.

Answer 19

Inferior colliculus

Question 20

The __ (located in the midbrain) takes the location data from the inferior colliculus and adds the 3rd dimension to it (vertical height) to create the spatial map of the sound’s location

Answer 20

Superior colliculus

Question 21

The __ has a tonotopic representation of the sounds- more rostral areas are activated by LOW frequency sounds, while caudal areas receive information about high frequency sounds

Answer 21

Primary auditory cortex (A1)

Question 22

The __ is composed of several different types of areas (Brocas, wernickes, etc.)

Answer 22

Auditory association cortex

Question 23

The __ has a lot of neurons that detect pure tones while the __, in contrast, has more neurons that are activated by complex sounds

Answer 23

Primary auditory cortex (A1)

Auditory association cortex

Question 24

Regarding the cochlear nuclei:
___ pathway: the nature of the sound (high, low)

___ pathway: the location of the sound

Answer 24

Ventral

Dorsal

Question 25

Regarding the superior olive nuclei:

___: differences in time of arrival to the ears

___: differences in intensity

Answer 25

Medial

Lateral

Question 26

___ is the spatial map of sound (where it is coming from)

___ creates a tonotopic map, beginning to know what the sound is

Answer 26

Inferior colliculus

Primary auditory cortex (A1)

Question 27

This membrane separates the perilymph from the scala vestibuli from the endolymph in the scale media

Answer 27

Reissner’s membrane

Question 28

Linear acceleration occurs in which planes?

Answer 28

Vertical or horizontal

Question 29

Angular acceleration occurs in what plane(s)?

Answer 29

Requires rotation around 1 or more planes

-Can include spin around vertical axis (spin kick), fall forward or backward

Question 30

Acceleration in the different planes is detected by:

Answer 30

• semicircular canals
• utricle (swelling where all 3 canals connect)
• saccule (below the utricle)

Question 31

Where is endolymph and perilymph found in the vestibular apparatus?

Answer 31

• Endolymph (high K+) inside the semicircular canals (anterior, posterior, lateral), utricle, and saccule
• Perilymph (high Na+) surrounds the vestibular apparatus

Question 32

___ is best situated to detect linear motion occurring on the horizontal plane, i.e., walking

Answer 32

Utricle

Question 33

___ is best situated for vertical (up and down) accelerations

Answer 33

Saccule

Question 34

A turning motion is best detected by the ___

Answer 34

Horizontal (lateral) canals

Question 35

Falling (or being thrown backwards) maximally activates the ___

Answer 35

Posterior semicircular canal

Question 36

Falling forward maximally activates the ___

Answer 36

Anterior semicircular canal

Question 37

The process of activating the different vestibular organs is similar to the cochlea-movement of hair cells in 1 direction is excitatory, movement in the opposite direction inhibits. In the semicircular canals, the __ is specialized for this process. In the utricle and saccule (otolith organs), the ___ is specialized for this process

Answer 37

Ampulla

Macula

Question 38

Motion of the body (particularly the head) will produce motion of the ___ in the appropriate vestibular organ, bending the hair cells inthe ampullae or macula and activating the nerves

Answer 38

Endolymph

Question 39

If falling forward, the eyes move ___

If falling backward, the eyes move ___

Answer 39

Up

Down

Question 40

If i fall forward, my eyes move UP to continue to focus as I fall forward and the anterior semicircular canal is activated. Which muscles are active and inhibited?

Answer 40

Superior rectus m.=ACTIVATED

Inferior rectus m.=INHIBITED

Question 41

If i fall backwards, my eyes move downward and the posterior semicircular canal is activated. Which muscles are activated and inhibited?

Answer 41

Superior oblique m.=ACTIVE

Inferior oblique m.=INHIBITED

Question 42

If i am spinning, depending on the direction of my turn, the ___ muscles are involved:

Answer 42

Lateral and medial recti muscles

Question 43

The vast majority of the cortical and cerebellar involvement in the vestibulooptic reflex is to ___

Answer 43

Suppress the reflex to allow for voluntary motion