Balance, Posture & Vestibular System Flashcards
What systems affect balance & posture?
- Vestibular
- Visual
- Somatosensory: muscle & joint proprioception
What are semicircular canals important for?
Head rotation
What do the otolith organs detect?
- Force of gravity & tilt of head
- Linear acceleration
What is the vestibular nerve composed of?
- Utricular nerve
- Saccular nerve
- Ampullary nerve
What are the 6 degrees of freedom?
- 3 translational: linear acc detected by utricle & saccule
- 3rotational: angular acc detected by semicircular canals
How does depolarisation & hyper polarisation occur?
- De= Kinocilia bend towards stereocilia
- Hyper-kinocilia bend away from stereocilia
What are hair cells made up of?
- Many stereocilia
- 1 kinocilium
What information does the macula detect?
- Static equilibrium
- Dynamic equilibrium
How is the macula in the utricle and saccule orientated?
- Utricle=horizontal
- Saccule=Vertical
What are the functional features of the semicircular canals?
- 3D space
- Main sensory structure
- Information on rotational movement & angular acc
What are the structural features of the semicircular canals?
- Contain endolymph
- Cupula(barrier against endolymph)= embedded cilia of hair cells
- Cupula bends in opposite direction to head rotation
What are sensory hair cells innervated by?
-Ampulla nerve
What are the functional pairs in the semicircular canals?
- L&R lateral/horizontal canals
- L.ant&R.post canals
- R.ant&L.post canals
What do cupula afferents project to? What does this lead to?
- Medial nucleus
- Medial efferents project to MN of neck/body to orientate head & stabilise retinal image
- Lateral efferents project to cerebellum & LMN to maintain body posture
What do otolith afferents project to?
Lateral nucleus
