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Balance and Equilibrium

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winniesmith's version from 2016-11-08 17:00

Section 1

Question Answer
Where is equilibrium sensedequilibrium sensations are provided by hair cells of the vestibular apparatus – semi-circular canals and otoliths
What do receptors in semi-circular canals respond too?Rotational movements
Describe the structure of the ampullaPart of the semi-circular canals. Where the hair cells are located. Also contains the crista- raised structure which also contains the receptors.
What are sterocilliaProjections which resemble long microvilli, displacement of the sterocilia either stimulates (towards kinosilium) or inhibits the hair cell.
Where are the sterocilliaembedded in the cupula- jelly like fluid filled
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Section 2

Question Answer
What do the otoliths do?sense accerlerations (closer to the cochlea)
what are the two types of otoliths?Utricle and Saccule
what does the utricle sense?horizontal linear accelerations
what does the saccule sense?Vertical linear accelerations/gravity.
How do the otoliths work?Simple receptor cells which contain hair cells. When the head is tilted the otolith moves due to gravity, distorting the hair cell processes, causing receptor output to increase.
What is the equilibrium pathway?Sensory neurons monitor hair cells of the otoliths and semi-circular canals. Afferent fibres form vestibular branch of the vestibulocochlear nerve. Fibres synapse on neurons in the vestibular nuclei
What are the roles of the vestibular nuclei1. Integrate sensory information arriving from each side of the head 2.Relay information to cerebellum 3. Relay information to cerebral cortex 4. Send commands to motor nuclei in brain stem and spinal cord
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