Anatomy of the Vestibular System

Question 1

SCCs - A) how many, B) sensitive to what type of acceleration

Answer 1

3, angular

Question 2

Otoliths: 1) how many, 2) sensitive to what type of acceleration

Answer 2

2, linear

Question 3

What does orthogonal mean?

Answer 3

Arranged at right angles to other 2 * As is the case with SCCs

Question 4

Identify 3 functional pairs of SCCs

Answer 4

LARP, RALP, bilatetal horizontal/lateral

Question 5

Identify reflex responsible for: 1) head stabilization, 2) upright posture, 3) retinal image stabilization

Answer 5

1) vestibulocollic, 2) vestibulospinal, 3) vestibuloocular

Question 6

Inner ear develops from 1 to 2 weeks AOG

Answer 6

4 to 25 weeks AOG

Question 7

1) First SCC to develop, 2) when?

Answer 7

Sup SCC, 6 weeks AOG

Question 8

Age when hair cells in the vestibular end organs are well differentiated

Answer 8

9 weeks AOG

Question 9

The organ of Corti is the last to mature at ___weeks AOG

Answer 9

25 weeks AOG

Question 10

What are the 2 maculae

Answer 10

Utricle, Saccule

Question 11

1) Up and down, 2) forward backward

Answer 11

Saccule, 2)utricle

Question 12

Duct shared by superior and posterior SCCS

Answer 12

Crus communis

Question 13

Fusion of utricular and saccular ducts

Answer 13

Endolymphatic duct

Question 14

Connects vestibular apparatus to the cochlear duct

Answer 14

Ductus reuniens

Question 15

2 cross over anastomoses between superior and inferior vestibular nerves

Answer 15

1)Voit’s anastomosis from Superior Vestibular Nerve to Saccule, 2) Oort’s anastomosis from Inferior Vestibular Nerve to Cochlear Nerve

Question 16

Another name for Scarpa’s Ganglion

Answer 16

Vestibular ganglion

Question 17

Blood supply of the vestibular end organs

Answer 17

1) Internal Auditoty/Labyrinthine Artery (from Ant Cerebellar, Sup Cerebellar or Basilar

Question 18

Branches of Labyrinthine Artery

Answer 18

Anterior vestibular, Common Cochlear

Question 19

What supplies Utricle, Sup SCC and Horizontal SCC

Answer 19

Ant Vestibular A.

Question 20

Branches of Common Cochlear A

Answer 20

Proper cochlear/spiral modiolar, Vestibulocochlear

Question 21

Branches of vestibulocochlear artery

Answer 21

Cochlear ramus and posterior vestibular artery

Question 22

What supplies posterior ampulla and major part of saccule

Answer 22

Posterior vestibular artery

Question 23

This is a true cilium that shows 9+2 arrangement of microtubules

Answer 23

Kinocilium

Question 24

Ampulla versus Macula

Answer 24

Ampulla dilated ends of SCC containing cupula, stereocilia and kinocilia; Macula (Utricle and Saccule)

Question 25

These are found in the upper surface of otolithic membranes, usually inorganic crystalline deposits

Answer 25

Otoconia or Otoliths

Question 26

These make up Otoliths/Otoconia

Answer 26

Calcium carbonate or calcite

Question 27

Specialized central region identifiable with a thin stripe running down the center of the otolith membranes of both maculae

Answer 27

Striola

Question 28

Kinocilia orient __1__ reversal line in saccule, _2__ reversal line in utricle

Answer 28

Away from sacule, towards utricle

Question 29

2 cell types in the sensory epithelium: 1) extend from the basement membrane to apical surface, with well developed Golgi complexes, many mitochondria, with many secretory granules likely responsible for formation of thr cupula; 2) contain a bundle of stereocilia in the apical surface

Answer 29

1)Supporting cells, 2) Hair cells

Question 30

T or F: Primary Vestibular afferents cross the midline

Answer 30

F

Question 31

Areas of the cerebellum where vestibular projections extend: 2 primary, 1 secondary

Answer 31

1) Primary: Vermis, Fastigial Nucleus, 2) Flocculus

Question 32

Matching type: 1)Sup Vestibular Nuc, 2)Dorsal Lateral VN, 3) Ventral Lateral VN; A) Vestibuloocular Reflex, B) Lat Vestibulospinal Tract (Vestibulospinal/Vestibulocollic Reflex) , C) Med Vestibulospinal Tract (Vestibulooculocervical Reflex)

Answer 32

1A 2B 3C

Question 33

Only vestibular nuclei without cerebellar projection

Answer 33

Dorsal lateral vestibular nucleus * Related to otolith function

Question 34

Reflex to stabilize vision during head movements, by moving eyes at the same speed but in the opposite direction

Answer 34

Vestibuloocular reflex

Question 35

Which tract aids in gaze stabilization, stabilizes head in shoulders by generating neck muscle contractions that resist passive head movement

Answer 35

Medial Vestibulospinal tract

Question 36

Which tract plays an important role in postural balance

Answer 36

Lateral vestibulospinal tract

Question 37

In unilateral labyrinthine lesions, tonic excitatory inout to ipsilateral postural extensors is reduced, especially when visual cues are absent. Tendency is to fall _away or toward_the side of the lesion

Answer 37

Toward