Auditory and Vestibular Pathways Flashcards
What determines loudness/intensity of sound?
amplitude
What determines pitch of sound?
frequency
what is timbre?
quality of the sound
How is sound heard?
air vibration eardrum -> ossicles vibration spreads to the cochlea converted by fluids in the cochlea into electrical impulses through transduction sound perceived in the auditory cortex
Where is the footplate of the stapes?
the oval window
What is impedance matching?
middle ear bones overcome sound loss by increasing sound pressure
How is sound amplified in the middle ear?
area ratio of the ear drum to footplate
lever action of ossicles
buckling of ear drum
What is important about the effect of sound on the basilar membrane?
the width and flexibility of the basilar membrane determines the distance a particular frequency travels - tonotopic organisation
High pitch distances travel far - T/F?
False
What are the hair cells in the organ of corti called?
stereocilia
How are stereocilia arranged?
in height order - deflection causes depolarisation/hyperpolarisaion and release of neurotransmitters - neural energy transferred to the brain
Why are the tips of hair cells linked?
connect transaction channels
Which signals do inner hair cells deal with?
afferent
Which signals to outer hair cells deal with?
efferent
What is the basis of tonotopy?
different frequencies of sound waves activate hair cells maximally at different locations
What is a simplistic pathway of sound perception?
cochlea
brainstem
cortex
What does the vestibular system provide for the brain?
information concerning gravity, rotation and acceleration
Which organs sense head angular acceleration? (head rotation)
semicircular canals
Which organs sense head linear acceleration?
saccule and utricle
What are the otolith organs?
utricle and saccule
What is the pathway of vestibular function?
peripheral sensory apparatus
central processing system
motor output system
What force deforms the hair cells in the labyrinth?
acceleration/gravity
What is the function of the semicircular canals?
detect head movements via rotational acceleration
What is the ampulla?
bulge in the canal where hair cells are located
What effect does movement have on the cilia?
movement causes fluid to circulate and displace the cupula
Why are the semicircular canals arranged in such a way?
to cover all planes of movement
What movement is sensed by otolith organs?
linear acceleration and gravity
What are otoconia made of?
calcium carbonate
What do striola do?
organise otoconia into narrow trenches in the otolith organs
Signals from the vestibular apparatus are constant - T/F?
True
What are the three main categories of output from the vestibular system?
orientation
postural control
eye movements
What is the function of the vestibulo-ocular reflex?
keeps the eyes still while the head moves in space
What si the function of the vestibulo-colic reflex?
keeps the head still in space while you move
What is the function of the vestibular spinal reflect?
adjusts posture for rapid changes in position
