Sensory System - Hearing & Balance Flashcards
What are the functions of the auditory system?
- peripheral mechano transducer (acoustic energy into nerve impulses)
- encodes environmental sounds including speech and music
- represents sound frequency, loudness and sound source location
What makes hair cells unique?
High level of extracellular K+ in endolymph fluid
What is the transduction pathway of sound?
- movement of hair cells causes tip lengths to stretch and opens K+ channels if cilia move towards the kinocilia
- K+ moves into cell
- depolarisation
- influx of Ca2+
- causes release of neurotransmitter
What is the organ of corti?
Where the hair cells are found
What moves and vibrated in hearing?
Basilar membrane
What’re do high frequency sounds cause the greatest amount of deflection?
Base of cochlear
Where do low frequency sounds produce the greatest deflection?
Apex of cochlear
Which type of hair cell is mostly responsible for transduction?
Inner hair cells
What is hearing loss caused by?
Damage to the outer hair cells which decreases hearing sensitivity
What do outer hair cells do?
Move
Their movement provides additional feedback to the basilar membrane
What do the otoliths organs provide information about?
Horizontal and vertical linear acceleration
What do the semicircular canals provide information about?
Angular acceleration of the head
What are the two otoliths organs?
Utricle
Saccule
What does the utricle detect?
Horizontal information
What does the saccule detect?
Vertical acceleration
