Auditory and Vestibular Systems

Question 1

How many stereocilia are in a bundle?

Answer 1

30-300

Question 2

What are the different types of links possible between sterocilla?

Answer 2

Lateral link connectors and tip links

Question 3

What are lateral link connectors?

Answer 3

Connections between shafts that hold the bundle together and allow it to move as a unit

Question 4

How do tip links work?

Answer 4

Tension in the tip links distort the sterocilia mechanically, which allows channels to open and close with cilia movement

Question 5

How do hair cells work?

Answer 5

Tip links open ion channels, that causes potassium ions to flow into the cell depolarising it.
Voltage gated calcium channels open which trigger neurotransmitter release at the synapse.

Question 6

What is the lateral line system?

Answer 6

Hair cell system that detects water movement along the outside of fish and amphibians

Question 7

What do mechanoreceptors in the lateral line system provide?

Answer 7

Information about movement through water or the directions and velocity of water flow

Question 8

What does the internal canal under the epidermis contain?

Answer 8

Mechanoreceptors called Neuromasts

Question 9

Where are superficial neuromasts found?

Answer 9

On fish/amphibians surfaces

Question 10

What encases the sterocilia bundles in fluid?

Answer 10

A gelatinous cupola

Question 11

What is the inner ear formed of?

Answer 11

Semicircular canals and cochlea

Question 12

What system is responsible for balance and motion in mammals?

Answer 12

Vestibular system

Question 13

Which system is the cochlea involved in?

Answer 13

Auditory system

Question 14

What is the vestibular system?

Answer 14

Balance and motion in mammals

Question 15

Which direction of rotation does the posterior semi-circular canal sense?

Answer 15

Roll around the X axis

Question 16

Which direction of rotation does the anterior semicircular canal sense?

Answer 16

Around the Y axis

Question 17

Which direction of rotation does the horizontal semicircular canal sense?

Answer 17

Around the z axis

Question 18

How do the hair cells sense rotation?

Answer 18

Cilia are connected to the gelatinous cupola
Under motion, fluid in the canals lag bc inertia
Pulls the cupola in the opposite direction to the rotation of the head, displacing cilia and depolarising hair cells

Question 19

How do the otolith organs work?

Answer 19

Hair cells are topped by a rigid layer of otoconia crystals

Under acceleration, the crystal layer is displaced, deflecting the cilia

Question 20

What is the quietest sound we can perceive and how much do the sterocilia move at this volume?

Answer 20

20 picoamps, 0.3mm

Question 21

What is the pathway of sound from the cochlea to the brain?

Answer 21

Change in air pressure -> change in fluid motion in the cochlea -> translated into electrical current in the cochlear nucleus-> olivary complex -> lateral lemniscus -> inferior colliculus -> medial geniculate body -> auditory complex

Question 22

What is another name for the outer ear?

Answer 22

Pinna

Question 23

What is the function of the Pinna?

Answer 23

Gathers sound from the environment and funnels it into the eardrum

Question 24

What is the Pinna made of?

Answer 24

Cartilage and covered with skin

Question 25

Which part of the ear filters high frequency (3000-5000 hz)?

Answer 25

Flange

Question 26

Which part of the ear filters very high frequency (>5000 hz)?

Answer 26

Conchae

Question 27

Which part of the ear filters low frequency?

Answer 27

Meatus

Question 28

What is grade I microtia?

Answer 28

Less than complete development of the external ear with identifiable structures and a small (but present) ear canal

Question 29

What is grade II microtia?

Answer 29

A partially developed ear with a closed stenotic external ear canal producing a conductive hearing loss

Question 30

What is grade III microtia?

Answer 30

Absence of the external ear with a small peanut-like vestige structure and an absence of the external ear canal and ear drum

Question 31

What is grade VI microtia?

Answer 31

Absence of the total ear or anotia

Question 32

What is another name for the eardrum?

Answer 32

tympanic membrane

Question 33

What connects the tympanic membrane to the oval window of the cochlea?

Answer 33

Ossicles

Question 34

What are the three ossicles?

Answer 34

Malleus, incus and stapes

Question 35

Which of the ossicles connect to the tympanic membrane?

Answer 35

Malleus

Question 36

Which of the ossicles connect to the oval window of the cochlea?

Answer 36

Stapes

Question 37

What are the ossicles positioned to create?

Answer 37

Amplification

Question 38

What is the space where the bones are usually filled with?

Answer 38

Air

Question 39

What is the swanky name for glue ear?

Answer 39

Otitis media

Question 40

What happens in otitis media?

Answer 40

Middle ear fills with fluid, impeding the ossicle motion

Question 41

What are the three chambers of the cochlea?

Answer 41

Scala vestibuli, Scala media and Scala tympani

Question 42

What does the Scala media contain?

Answer 42

Components for sound transduction

Question 43

What happens when the stapes move back and forth?

Answer 43

Creates compression and rarefaction in the fluid of the chambers

Question 44

What does the basilar membrane do?

Answer 44

Filters sound according to frequency

Question 45

What is the basilar membrane like far from the oval window?

Answer 45

Stiff and narrow

Question 46

What is the basilar membrane like close to the oval window?

Answer 46

Stiff and narrow

Question 47

What is the basilar membrane like at the non-oval window end?

Answer 47

Wide and compliant

Question 48

What frequencies will the basilar membrane pick up close to the oval window?

Answer 48

High

Question 49

What frequencies will the basilar membrane pick up far away from the oval window?

Answer 49

Lower

Question 50

What is the organ of corti?

Answer 50

Membrane that inner and outer hair cells are mounted on

Question 51

Do the outer or inner hair cells contact the tectorial membrane?

Answer 51

Outer

Question 52

Where does the organ of corti sit?

Answer 52

On top of the basilar membrane within the scala media

Question 53

How are inner hair cells arranged?

Answer 53

Straight line

Question 54

What type of synapse do the inner hair cells have?

Answer 54

Afferent

Question 55

What type of synapse do the outer hair cells have?

Answer 55

Efferent

Question 56

How are the outer hair cells arranged?

Answer 56

Bundles of arches

Question 57

What does an influx of positive ions do to the outer hair cells?

Answer 57

Causes them to contract

Question 58

What happens when the outer hair cells contract?

Answer 58

Causes the basilar and tectoral membranes get closer to one another, causing the inner hair cell to move

Question 59

By how much does the cochlea amplify sound by?

Answer 59

50dB

Question 60

Are loud sounds amplified in the cochlea?

Answer 60

No

Question 61

What drives cochlear cells?

Answer 61

High potassium concentration of the endolymph of the scala media