vestibular system Flashcards
what is the function of the vestibular system?
balance
maintain head posture
control of eye muscles for image stability
Info from this system gets sent to midbrain
what is the vestibular system composed of?
vestibular sacs and semi-circular canals
what are vestibular sacs?
composed of saccule and utricle
they are sensitive to the force of gravity and inform about the heads orientation
these detect forward and backwards movement
utricle= horizontal plane
saccule= vertical movement
what are semi circular canals?
ring like structures that approximate the sagittal, transverse, and horizontal planes of movement.
each canal can interpret one type of head movement
the canals are filled with fluid called endolymph which travels to the ampulla where hair cells called stereocilia are present. Movement of this fluid causes movement of these hair cells which causes release of NT to send info about plane of movement to the midbrain
more info on utricle and sacuule
these are used to detect linear acceleration and whether our head is in an anatomical position. Within this is Otoconia.
Role of otoconia- utricle and saccule contain an otolithic membrane which contains hair tuffs and otoconia (also known as ear crystals) on top of the membrane. If you change equilibrium e.g. head moves, otoconia move which causes the membrane to move which causes the hair tuffs to move, depending on which direction different signal’s will be sent through the nerve fibers and the axons through to the vestibular division of the cranial nerve and transmitted to the brain.
this is linked to vertigo
