Block 2 Exam: Auditory And Vestibular Systems

Question 1

The vestibular systems has ___ otolith organs. What are they and what do they detect?

Answer 1

Utricle and Saccule.

They detect changes in head angle/linear acceleration.

Question 2

Each otolith organ in the vestibular system contains a _______. How is this orientated in each organ?

Answer 2

Macula

Vertically oriented in Saccule

Horizontally oriented in Utricle

Question 3

What does the vestibular system used to detect head rotation?

Answer 3

3 semicircular canals at 90 degrees to each other.

Question 4

Vestibular system:

______ & _____ are 30 degrees parallel to earth and perpendicular to gravity.

Answer 4

Semicircular canal/utricle

Question 5

The macula of odolith organs contain ___ whose cilia project into gelantinous cap.

Answer 5

Hair Cells

Question 6

The calcium carbonate crystals on top of the cap in vestibular system which weigh on cap and move due to gravity are called…

Answer 6

Otoliths

Question 7

Hair cells are tonically active, which means

Answer 7

When head angle changes, amount of depolarization/hyperpolarization changes.

Question 8

Vestibular: When cilia towards kinocilium

Answer 8

depolarize, excite afferents, Ca2+ and K+ flow

Question 9

Vestibular: When cilia away from kinocilium

Answer 9

hyperpolarize, inhibit afferents, no Ca2+/K+ flow

Question 10

Vestibular Semicircular canals:

The Ampulla has a sensory receptor called ____.

Answer 10

Crista

Question 11

Vestibular system:

_______ of hair cells synapses on vestibular nerve.

Answer 11

Basal Membrane

Question 12

What Nerve is the vestibular nerve?

Answer 12

Cranial Nerve 8

Question 13

Vestibular nerve (#8) —> Lateral Vestibular Nucleus Pathway

Answer 13

Nerve 8 –> Lateral Vestibular Nucleus –> Cerebellum & Limb motor neurons

Question 14

Vestibular nerve (#8) –> Medial Vestibular Nucleus Pathway

Answer 14

Nerve 8 –> Medial Vestibular Nucleus –> MEDIAL LONGITUDINAL FASISCULUS –> Extraocular motor areas (3,4,6) and neck motor neurons.

Question 15

Where does most vestibular info go through in thalamus?

What lobe of the cortex gets most vestibular info?

Answer 15

Ventral posterior lateral nucleus of thalamus (VPL)

Parietal Lobe

Question 16

What cortical areas receive direct vestibular projections straight from VPL?

Answer 16

Areas 3a, T3, and PIVC (parietoinsular vestibular cortex –> insular area)

Question 17

What are these 3 other areas that get vestibular info and what do they do?

1. VIP
2. MST
3. Frontal eye fields/superior colliculus

Answer 17

VIP: ventral intraparietal area–> Grasping things, where an item is in space

MST–> Medial superior temporal area–> some vestibular/vision info

Frontal eye fields/superior colliculus–> Eye localization

Question 18

What are the functions of the vestibulocerebellum?

Answer 18

Position of head/body in space, equilibrium, eye orientation

Question 19

COWS: Warm Water

*COWS is talking about horizontal nystagmus

Answer 19

Endolymph in ipsilateral horizontal canal rises, resulting in increased firing.

Eye toward contralateral (opposite ear from where water put in), with horizontal nystagmus (quick horizontal eye movement) to ipsilateral ear.

Question 20

COWS: Cold Water

Answer 20

Endolymph falls, decrease rate of firing.

Eyes toward ipsilateral (same side) ear, horizontal nystagmus to contralateral ear.

Question 21

What is pitch encoded as?

Answer 21

Frequency

low frequency = low sound

Question 22

What is intensity (amplitude) of sound encoded as?

Answer 22

Loudness

Question 23

Sound waves Pathway:

Pinna —> auditory canal –> move ________ —> ________, which move the membrane at oval window —> moves fluid in _____ –> Response in sensory neurons.

Answer 23

Pinna –> auditory canal –> move tympanic membrane (ear drum) –> ossicles, which allow larger pressure on cochlea –> membrane at oval window –> moves fluid in cochlea –> response in sensory neurons.

Question 24

Sound waves move…

Ossicles move…

Oval Window moves…

Answer 24

Tympanic membrane

Membrane at oval window

fluid in cochlea

Question 25

Ossicles amplify changes in pressure by altering ____ to help transduce waves into electrical energy.

Answer 25

force/surface area.

Question 26

_____ moves in/out like a piston transmitting sound vibrations to inner ear at oval window.

Answer 26

Footplate of stapes

Question 27

Pressure=

Answer 27

Force/Area Ossciles increase fore and decrease surface area at oval window.

Question 28

When you have a cold, ______ tube is clogged. Children's is horizontal, so it gets infected because it is hard to drain.

Answer 28

Eustachian tube

Question 29

What contains auditory receptor cells? (Hint: surrounded by tectorial membrane)

Answer 29

Organ of Corti

Question 30

The fact that endolymph has an electrical potential 80 mV higher than perilymph is known as...

Answer 30

Endocochlear potential

Question 31

What participates in active transport to maintain concentration gradients?

Answer 31

Stria Vascularis

Question 32

Higher Frequency sounds processed by hair cells that are close to ____. Describe this.

Answer 32

Stapes Base vibrates a lot, dissipates most energy and does not travel far.

Question 33

Lower frequencies sounds travel down _______

Answer 33

Basilar membrane, travels down membrane.

Question 34

The fact that the basilar membrane's response establishes a place code in which different locations on the membrane are maximally deformed by different frequencies is known as....

Answer 34

Neural Coding of Pitch

Question 35

Basalar membrane: | Base end vs. Apex end

Answer 35

Apex: Wide/floppy, low frequency, 500Hz, 1kHz Base: Narrow/stiff, high frequency, 16kHz

Question 36

What are the sensory receptor cells of auditory system? Outer hair cells lie towards ____ Inner hair cells more towards _____

Answer 36

Hair cells. Outer towards Apex Inner towards modiulus

Question 37

What do the rods of corti do in the organ of corti?

Answer 37

support hair cells.

Question 38

A critical step in transduction of sound to neural signal involves _________ that bend hair cells.

Answer 38

Up/down oscillations

Question 39

Hair cell apical surfaces has _____ stiffened cilia called stereocilia arranged in ascending height

Answer 39

50-100

Question 40

___% of spiral ganglion neurons communicate with a small number of hair cells. __% receive input for outer hair cells. Inner hair cells innervate about ___ spiral ganglion cells.

Answer 40

95% 5% 10

Question 41

Motor innervation causes stereocilia to move up/down in order to

Answer 41

amplify sounds and enhance tectorial membrane movements.

Question 42

What part of the auditory pathway is responsible for processing interaural time differences and localizing sounds in space.

Answer 42

The superior olive (and further as it projects to inferior colliculus).

Question 43

The Lateral Lemiscus travels from...

Answer 43

Superior Olive --> Inferior Colliculus --> MGN

Question 44

Integration of visual and auditory information is accomplished by...

Answer 44

Reciprocal projections from inferior colliculus back to the superior colliculus.

Question 45

An involuntary muscle contraction that occurs in the middle ear in response to high-intensity sound stimuli or when the person starts to vocalize is processed by feedback (brain stem neurons send axons to outer hair cells). What is this called?

Answer 45

Attenuation reflex

Question 46

Each cochlear nucleus receives input from one ear on the ___ side. All other auditory information is from both ears. What is the only way that brain stem damage can produce damage in one ear?

Answer 46

Ipsilateral If the cochlear nucleus or auditory nerve on one side is damaged.

Question 47

Tonotophic Mapping: What is it? Higher frequencies more ____. Lower frequencies more _____.

Answer 47

Different frequencies at different points. This is continuous in auditory system (visible in brain). Higher frequencies more rostral. Lower frequencies more Caudal.

Question 48

What frequencies use phase locking on every cycle or some fraction of cycles combined with tonotopic detection? What frequencies rely on tonotopy alone?

Answer 48

Low frequencies (<3kHz) High frequencies

Question 49

Name the 3 properties of sound.

Answer 49

1. Frequency (tonoophy and phase locking) 2. Intensity (encoded by # axons/AP fired) 3. Source- can be horizontal or vertical

Question 50

Horizontal Source: Name the two types of processing and where they occur

Answer 50

Interaural time delay: medial superior olive Interaural intensity difference- processed by lateral superior olive and medial nucleus of trapezoid body (MNTB).

Question 51

Vertical Source

Answer 51

Reflections off pinna Processing by cochlear nucleus and superior olivary nucleus.