the vestibular system Flashcards
what 2 questions does the vestibular system answer
where am i going
which way is up
how does the vestibular system make sense of where you are
head angular acceleration (head rotation)
head linear acceleration (gravity)
all three dimensional moving bodies have _ degrees of freedom
6
all three dimensional moving bodies have 6 degrees of freedom
how are they organised
3 are translational
3 are rotaional
what is translational motion
linear movements in an x, y, z acis
what is rotational motion
bodys rotation rlative to the x, y, z axis
what is apparatus is known as the vestibular organ
peripheral sensory apparatus
what does the peripheral sensory appartus do
detects and relays info about head angular and linear velocity to central processing system
orientates the head with respect to gravity
what does the central processing system do
processes info in conjunction with other sensory inputs for position and movement of head in space
what does the motor output system do
generates compensatory eye movements and compensatory body movements during head and postural adjustments
vestibular organ
labyrinth = ___________+_______
vestibular organ + cochlea
what is the function of the semi-circular canals (in ear)
detect head movement via rotatory acceleration
in the semicircular canal what is the crista
sheet of cells where hair cells are clustered
in the semicircular canals, what is the ampulla
bulge along canal, contains crista (sheet of cells)
in the semicircular canal, what is the cilia
project into gelatinous cupula
in the semicircular canals what is the kinocili
orientated in same direction so all excited or inhibited together
what are the semicircular canals filled with
endolymph
in the semi circular canals, movement causes endolymph fluid to
circulate and displace cupula
what do otolith organs sense
linear acceleration and gravity
what is the otolith organs made up of
saccule and utricle
what do the utricle and saccule make up
otolith organs
what does the saccule sense
movement in the vertical/saggital plane
what does the utricle sense
movement in the horizontal plane
in the otolith organs, what are otoconia
crystals of calcium bicarbonate
what does striola do
serves as a structural landmark and arranges otoconia into narrow trenches dividing into otolith
the signals in the vestibular nerve are (tonic/hasic)
tonic
what are the 3 vestibular reflexes
vestibulo-ocular reflex
vestibulo-colic reflex
vestibular-spinal reflex
what is the vestibulo-ocular reflex
keeps the eyes still in space when the head moves
what is the vestibulo-colic reflex
keeps the head still in space - or on a level plane when you walk
what is the vestibulo-spinal reflex
adjusts posture for rapid changes in position
what does the vestibulo ocular reflex cause your eyes to do in head movement
eyes move in the opposite direction to head
speed of the eye movement equals that of head movement
allows objects to remain in focus during head movement
if you move your head to the left, you will (excite/inhibit) the left horizonal canal, (exciting/inhibiting) the right
if you move your head to the left you will EXCITE the left horizontal canal, INHIBTING the right
