Anatomy of the Vestibular System Flashcards
SCCs - A) how many, B) sensitive to what type of acceleration
3, angular
Otoliths: 1) how many, 2) sensitive to what type of acceleration
2, linear
What does orthogonal mean?
Arranged at right angles to other 2 * As is the case with SCCs
Identify 3 functional pairs of SCCs
LARP, RALP, bilatetal horizontal/lateral
Identify reflex responsible for: 1) head stabilization, 2) upright posture, 3) retinal image stabilization
1) vestibulocollic, 2) vestibulospinal, 3) vestibuloocular
Inner ear develops from 1 to 2 weeks AOG
4 to 25 weeks AOG
1) First SCC to develop, 2) when?
Sup SCC, 6 weeks AOG
Age when hair cells in the vestibular end organs are well differentiated
9 weeks AOG
The organ of Corti is the last to mature at ___weeks AOG
25 weeks AOG
What are the 2 maculae
Utricle, Saccule
1) Up and down, 2) forward backward
Saccule, 2)utricle
Duct shared by superior and posterior SCCS
Crus communis
Fusion of utricular and saccular ducts
Endolymphatic duct
Connects vestibular apparatus to the cochlear duct
Ductus reuniens
2 cross over anastomoses between superior and inferior vestibular nerves
1)Voit’s anastomosis from Superior Vestibular Nerve to Saccule, 2) Oort’s anastomosis from Inferior Vestibular Nerve to Cochlear Nerve
Another name for Scarpa’s Ganglion
Vestibular ganglion
Blood supply of the vestibular end organs
1) Internal Auditoty/Labyrinthine Artery (from Ant Cerebellar, Sup Cerebellar or Basilar
Branches of Labyrinthine Artery
Anterior vestibular, Common Cochlear
What supplies Utricle, Sup SCC and Horizontal SCC
Ant Vestibular A.
Branches of Common Cochlear A
Proper cochlear/spiral modiolar, Vestibulocochlear
Branches of vestibulocochlear artery
Cochlear ramus and posterior vestibular artery
What supplies posterior ampulla and major part of saccule
Posterior vestibular artery
This is a true cilium that shows 9+2 arrangement of microtubules
Kinocilium
Ampulla versus Macula
Ampulla dilated ends of SCC containing cupula, stereocilia and kinocilia; Macula (Utricle and Saccule)
These are found in the upper surface of otolithic membranes, usually inorganic crystalline deposits
Otoconia or Otoliths
These make up Otoliths/Otoconia
Calcium carbonate or calcite
Specialized central region identifiable with a thin stripe running down the center of the otolith membranes of both maculae
Striola
Kinocilia orient __1__ reversal line in saccule, _2__ reversal line in utricle
Away from sacule, towards utricle
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
1)Supporting cells, 2) Hair cells
T or F: Primary Vestibular afferents cross the midline
F
Areas of the cerebellum where vestibular projections extend: 2 primary, 1 secondary
1) Primary: Vermis, Fastigial Nucleus, 2) Flocculus
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)
1A 2B 3C
Only vestibular nuclei without cerebellar projection
Dorsal lateral vestibular nucleus * Related to otolith function
Reflex to stabilize vision during head movements, by moving eyes at the same speed but in the opposite direction
Vestibuloocular reflex
Which tract aids in gaze stabilization, stabilizes head in shoulders by generating neck muscle contractions that resist passive head movement
Medial Vestibulospinal tract
Which tract plays an important role in postural balance
Lateral vestibulospinal tract
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
Toward
