Balance, posture and vestibular system Flashcards
(19 cards)
What are the otolith organs and where are they contained?
Utricle and saccule
In the vestibule
Vestibular nerve is comprised of? (3)
Utricular nerve
Saccular nerve
Ampullary nerve
what are the 6 degrees of freedom?
X,Y,Z
Roll, pitch, yaw
Translational motion and linear acceleration is detected by?
Utricle and saccule
Rotational motion and angular acceleration is detected by?
Semicircular canals
Maculae are made up of what 3 components?
Supporting cells
Hair cells
Otolithic membrane (CaCO3 crystals)
Hair cells are made of?
Single kinocilium and many stereocilia
Tilt of cilia to the left =?
Depolarisation/increased firing
Macula provides info about which 2 things?
Dynamic and static equilibrii
Macula in the utricle is (horizontal or vertical)?
Horizontal
Macula in the saccule is (horizontal or vertical)?
Vertical
Name the three semicircular canals
anterior
posterior
lateral
Main sensory structures of the SSCs are localised to what structure?
Ampulla
What is in the ampulla?
Cupula- gelatinous mass that the cilia of hair cells are embedded in
What is the effect of head rotation on the cupula?
Distorts it due to endolymph and activates the ampullary nerve. Depolarisation increases on one side and decreases on the other.
What direction does the cupula bend in relative to head rotation?
Opposite direction
What are the pairs arrangement of the SSCs on each side?
L+R lateral together
L anterior with R posterior and vice versa
Where does the sensory pathway go from the cupula?
Ampullary nerve –> Vestibular nerve –> CNVIII –> medial vestibular nucleus –> motor neurons of neck/trunk to orientate head and stabilise retinal image (vestibulo-ocular reflex)
Where do afferents from the utricle and saccule go?
Ampullary nerve –> Vestibular nerve –> CNVIII –> lateral vestibular nucleus–> cerebellum and limb motor neurons to maintain upright body posture
