Vestibular System

Question 1

List and describe the 3 ear divisions

Answer 1

• outer = capture sound waves
• middle = convert waves to vibrations
• inner = convert vibrations to nerve impulses

Question 2

Which structure of the ear also aids in maintaining balance in space?

Answer 2

Inner ear

Question 3

What is the specialized cell that aids in balance that contains nerve endings and mechanoreceptors?

Answer 3

Stereocilia

Question 4

The outer and middle ear are innervated by which nerves?

Answer 4

Auricular and facial n

Question 5

Describe Inner ear innervation

Answer 5

CN 8 - vestibulocochlear

Question 6

Where is the internal ear located?

Answer 6

Petrous part of temporal bone

Question 7

Which labyrinth contains perilymph?

Answer 7

Bony labyrinth

Question 8

Endolymph is located in?

Answer 8

Membranous labyrinth

Question 9

The cochlear duct has ___________ function and ___________ sound processing

Answer 9

Auditory; sensory

Question 10

In the inner ear, which structure is associated with balance?

Answer 10

Semicircular duct

Question 11

The semicircular duct lies in the ________________ of the bony labyrinth

Answer 11

Semicircular canal

Question 12

How many semicircular canals in the bony labyrinth?

Answer 12

3

Question 13

The __________ connects the cochlea to the semicircular canals

Answer 13

Vestibule

Question 14

Define the cochlear

Answer 14

Spiral tunnel around axis of spongy bone called modiolus

Question 15

The enlarged portion of the semicircular ducts is called the?

Answer 15

Ampulla

Question 16

Within the ampulla is a specialized innervation called the _____________ that contain the hair cells?

Answer 16

Crista ampularis

Question 17

The _________ and ___________ are housed in 2 depressions of the vestibule

Answer 17

Utricle and saccule

Question 18

What are the 3 semicircular canal pairs?

Answer 18

• posterior
• anterior/superior
• horizontal/lateral

Question 19

Which semicircular canal is concerned with dynamic position of the head in 3 perpendicular planes??

Answer 19

Horizontal/lateral

Question 20

True or false: The lateral semicircular canal pair is sensitive to constant velocity rotation

Answer 20

False

Question 21

List the 2 otolith organs

Answer 21

• utricle
• saccule

Question 22

Linear acceleration and static position of the head are associated with which otolith organ?

Answer 22

Saccule

Question 23

Type 1 hair cells are characterized by ?

Answer 23

Narrow neck and rounded base

Question 24

Type II hair cells are _______________ in shape

Answer 24

Cylindrical

Question 25

Which type of hair cells are likely only inhibitory?

Answer 25

Type I

Question 26

True/False: Type 2 hair cells are innervated only by afferent fibers

Answer 26

False, they are innervated by both

Question 27

Where do afferent fibers direct their projections to?

Answer 27

CNS

Question 28

Where does bending need to occur to depolarize the cell (activate it)?

Answer 28

Towards kinocilium

Question 29

Bending away from the kinocilium will ____________ the cell

Answer 29

Hyperpolarize/inhibit

Question 30

What does the crista ampullaris contain?

Answer 30

Strereocilia (includes kinocilium), tip link, gelatinous cúpula, nerve supply

Question 31

What are adjacent stereocilia linked by?

Answer 31

Tip links

Question 32

Where do sensory hair cells project into ?

Answer 32

Gelatinous cupulla

Question 33

What is the function of the cúpula?

Answer 33

Allow for uniform movement of hair cells

Question 34

Cells in the macula are ___________ (flat/dome)

Answer 34

Flat

Question 35

Describe endolymph movement when the head is moving

Answer 35

Endolymph moves opposite to the direction of the head

Question 36

True/false: An increase in firing occurs toward the direction of the head

Answer 36

True

Question 37

Define nystagmus

Answer 37

involuntary eye movement to stabilize the image on the retina

Question 38

Describe rotational nystagmus

Answer 38

Eyes move slowly opposite to rotation and quickly in direction of movement

Question 39

Which nystagmus is accompanied by vertigo and muscle contractions, appropriate for virtual rotation?

Answer 39

Post-rotational (reversed movements to rotational)

Question 40

Describe the vestibulo-ocular reflex

Answer 40

Head turns left = output from left vestibular nucleus inhibits and excites right = eye moves right because of contraction and relaxation of muscles *LR6 *DO4

Question 41

Where are kinocilium embedded?

Answer 41

Gelatinous cupula

Question 42

In the cupula, what is embedded that helps with hair cells movement?

Answer 42

Otoliths-Ca carbonate crystals

Question 43

What is the midline between utricle and saccule?

Answer 43

Striola

Question 44

Describe direction of stereocilia on each side of the striola

Answer 44

Opposite on either side of striola

Question 45

Describe orientation of macula of utricle

Answer 45

Horizontally

Question 46

Describe orientation of macula of saccule

Answer 46

Vertically