The Vestibular System

Question 1

What are otoconia?

Answer 1

calcium carbonate crystals in the saccule and utricle

Question 2

Each vestibular hair cell has a bundle of _____-filled stereocilia projecting from its apical surface in a staircase-like pattern.

Answer 2

actin

Question 3

This is a specialized patch of epi in the ampulla of the semicircular canals that contains the sensory hair cells.

Answer 3

crista

Question 4

Each hair cell has a single _____, which is the tallest cilium located at one side of the hair bundle.

Answer 4

kinocilium

Question 5

In the saccule, the hair bundles are oriented facing ____ the striola.

Answer 5

away from

Question 6

Within each crista, all of the hair cells have their stereocilia _____.

Answer 6

oriented the same way

Question 7

Adjacent cilia are connected by ____ which are attached at their lower end to ion channels.

Answer 7

tip links

Question 8

The base of the hair cells is bathed in _____.

Answer 8

perilymph

Question 9

From where does the inferior (descending) vestibular nucleus receive input?

Answer 9

the utricles, saccule, and semicircular canals, with spinal and cerebellar input, too

Question 10

What is the function of the semicircular canals?

Answer 10

they detect angular acceleration

Question 11

From where does the lateral (Deiter’s) vestibular nucleus receive input?

Answer 11

the utricles, with spinal and cerebellar input, too

Question 12

The medial and superior vestibular nuclei give rise to the _____.

Answer 12

medial longitudinal fasciculus

Question 13

Where is the saccule?

Answer 13

it hangs vertically on the lateral wall of the vestibule

Question 14

What is the otolithic membrane? What is its purpose?

Answer 14

a gelatinous mass that holds the otoconia in place

Question 15

Vestibular afferent nerves project to the _____.

Answer 15

ipsilateral vestibular nuclei at the border of the caudal pons and rostral medulla

Question 16

From where does the superior vestibular nucleus receive input?

Answer 16

the semicircular canals

Question 17

In the utricle, the axes of polarity of the hair cells is towards the _____.

Answer 17

striola

Question 18

What tract does the medial vestibular nucleus comprise?

Answer 18

medial longitudinal fasciculus

Question 19

lateral (Deiter’s) vestibular nucleus –> lateral vestibulospinal tract –> _________ (outcome)

Answer 19

excitation of extensor muscles of the limbs

Question 20

What are the vestibular sensory organs?

Answer 20

• the utricle
• the saccule
• the 3 ampullae of the semicircular canal organs

Question 21

What are the 4 major vestibular nuclei?

Answer 21

superior lateral (Deiter’s) medial inferior (descending)

Question 22

Where is the utricle?

Answer 22

at the floor of the vestibule

Question 23

What detects linear acceleration of the head and position w/ respect to gravity?

Answer 23

the otolith organs

Question 24

What do the otolith organs do?

Answer 24

detect linear acceleration of the head and position w/ respect to gravity

Question 25

What is the striola?

Answer 25

a central region of the epithelium in the utricle and saccule

Question 26

The semicircular canals project mainly to the \_\_\_\_\_.

Answer 26

medial and superior vestibular nuclei

Question 27

In the anterior and posterior canals, the hair cells are oriented with their kinocilia facing \_\_\_\_\_.

Answer 27

away from the utricle

Question 28

What is the swelling at the end of each semicircular canal?

Answer 28

the ampulla

Question 29

What hair bundles would inform the brain if you were riding in an elevator?

Answer 29

the saccular hair bundles

Question 30

Vestibular afferent nerves have cell bodies in \_\_\_\_\_.

Answer 30

Scarpa's ganglion

Question 31

These are calcium carbonate crystals in the saccule and utricle.

Answer 31

otoconia

Question 32

Since the saccular hair bundles project horizontally, they are sensitive to ____ displacement of the head.

Answer 32

vertical

Question 33

The hair bundles are bathed in \_\_\_\_\_.

Answer 33

endolymph

Question 34

In the _____ canals, the hair cells are oriented with their kinocilia facing towards the utricle.

Answer 34

horizontal semicircular

Question 35

The utricles send afferents to the _____ and also to the \_\_\_\_\_.

Answer 35

lateral vestibular nucleus; medial and inferior nucleus

Question 36

What is found within each ampulla? What does it contain?

Answer 36

the crista containing the sensory hair cells

Question 37

In the ______ canals, the hair cells are oriented with their kinocilia facing away from the utricle.

Answer 37

anterior and posterior

Question 38

What happens when the tip links pull the bundle towards the kinocilium?

Answer 38

the mechano-transduction channels open --\> cations from endolymph enter hair cells --\> depolarizes --\> NT released

Question 39

inferior (descending) vestibular nucleus --\> vermal cerebellum --\> ______ (location)

Answer 39

reticular formation and brainstem

Question 40

What detects angular acceleration?

Answer 40

the semicircular canals

Question 41

The saccule, utricle, and semicircular canals all project to the \_\_\_\_.

Answer 41

inferior vestibular nucleus

Question 42

What tract does the lateral (Deiter's) vestibular nucleus comprise?

Answer 42

the lateral vestibulospinal tract

Question 43

In the horizontal semicircular canals, the hair cells are oriented with their kinocilia facing \_\_\_\_\_\_.

Answer 43

towards the utricle

Question 44

When do mechano-tranduction channels open?

Answer 44

when the tip links pull the bundle towards the kinocilium

Question 45

What is the crista?

Answer 45

a specialized patch of epi in the ampulla of the semicircular canals that contains the sensory hair cells

Question 46

From where does the medial vestibular nucleus receive input?

Answer 46

the utricles and semicircular canals

Question 47

medial vestibular nucleus --\> medial longitudinal fasciculus --\> _____ (outcome)

Answer 47

coordination of eye and head movements

Question 48

In the \_\_\_\_, the axes of polarity of the hair cells is towards the striola.

Answer 48

utricle

Question 49

Hair cells convert _____ stimuli to \_\_\_\_\_.

Answer 49

mechanical --\> receptor potentials

Question 50

In the \_\_\_\_, the hair bundles are oriented facing away from the striola.

Answer 50

saccule

Question 51

What do the semicircular canals do?

Answer 51

detect angular acceleration