4. Bony labyrinth
3 parts
Vestibule
Semicircular canals
Cochlea
Friday, June 19, 2020
5. Membranous labyrinth
In bony labyrinth
Filled with endolymph.
Surrounded by perilymph.
Consists of
Utricle & saccule – in bony
vestibule
Semicircular ducts – in
canals
Ducts of cochlea – in
cochlea
Friday, June 19, 2020
7. Semicircular canals
Anterior
Posterior
Lateral
One end of each dilated
– ampulla which
contains receptor organ
– crista ampullaris.
They open into utricle
by 5 orifices.
Friday, June 19, 2020
8. Otolith organs
Utricle & saccules
together called –
Otolith organs.
Utricle – larger, opens 3
semicircular canals
Connected to saccules &
endolymphatic sac
Saccules
Connected to utricle &
cochlea – ductus reunion.
Friday, June 19, 2020
9. Vestibular receptors
Hair cells
Location – of
semicircular canals in
mass of tissue within
ampulla- crista
ampullaris.
Of otolith organs in
macula.
Friday, June 19, 2020
15. Receptors in otolith organs
macula
Structure
Neuroepithelium
Supporting cells
Otolith membrane.
Contains crystals of Ca
carbonate – otoliths or
otogonia
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16. Stimulation of receptors in
otolith organs.
Macula of utricle
Linear acceleration.
Macula of saccule
Vertical acceleration.
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20. Mechanism of functioning
Mechanism of
stimulation –
At the beginning of
movements
At the end of
movements.
Mechanism of
adaptation. – after
15-20 sec of
continuous movement.
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21. Functions
Utricle –
Stimulated during
horizontal acceleration
Saccules –
Stimulated during
vertical acceleration
Friday, June 19, 2020