Vestibular Function Flashcards
what is the function of the vestibular system?
controls posture and balance
where is the vestibular system found in the body?
inner ear
what are the name of the semi circular membraneous tubes?
labyrinths
what bone is the semi circular canals embedded into?
temporal bone
what fills the labyrinth tubes?
endolymph
state the importance of the structure of the semi circular canals
the canals are at 90 degrees to each other so tubes can detect movement in 3 dimensions
state the three structures which make up the vesicular system
- 3 semi circular canals
- utricle
- saccule
what is the swelling at the base of the semi circular canals called?
ampulla
what structure connects the three semi circular tubes together ?
the utricle
where are sensory hair cells found?
ampulla
utricle
saccule
what is the utricle and the saccule collectively known as ?
otolith organs
what structure in the vestibular system detects linear acceleration?
utricle
saccule
- otolith organs
what structure in the vestibular system detects rotational acceleration?
semi circular canals
what are the sensory receptors called which are present in the ampulla?
cristae
how many ampulla are there in the inner ear?
3
- one of each semi circular canal
what is the gelatinous structure which structure across the ampulla ?
cupula
how does the endolymph in the semi circular canals affect the ampulla?
when the endolymph moves in one direction the crista and cupula is pushed in the same way. This affects the cilia of the hair cells which directly synapse with the vestibular nerve.
state the two types of cilia of the hair cells
- kinocilium
- sterocilia
which of the two hair cell cilia are longer ?
kinocilium
state how rotational acceleration is detected when the head is rotated suddenly
- the ampulla moves with the bone
- endolymph stays stationary for a moment due to its own inertia
- the endolymph then produces drag and bends the cupula in the opposite direction
- as the endolymph catches up with the acceleration the cupula becomes unbent
- at a sudden stop, the bone stop moving so the ampulla is stationary but the endolymph still has its momentum so continues the path it had.
- this causes the cupula to be bent in the opposite direction
- this causes sense of movement and dizziness
distortion of cilia towards the kinocilium causes ?
- depolarisation
- hyper polarisation
depolarisation
- increase APs