INT PHYS EXAM1 studyguide4

• pinna
• ear canal
• typanic membrane

• malleus
• incus
• stapes

• oval window
• cochlea
• cochlear duct
• tympanic duct
• round window

• sound waves vibrate tympanic membrane which causes the bones of the inner ear to vibrate
• vibration of stapes is translated to the oval window which causes vibrations in the fluid of the inner ear
• the movement of fluid in cochlear duct moves the tectorial membrane which then moves cilia on hair cells

• as a hair cell is bent in one direction it causes the cell to depolarize and release more glutamate to initiate greater AP frequency in the associated sensory neuron
• the louder the sound, the greater the depolarization, and the greater the frequency of AP's generated in the afferent neurons

• Membrane stiffer/narrower near the oval window(start)
• membrane wide/flexible near helicotrema(end)
• HIGH freq - causes greatest deflection of oval window
• LOW freq - causes greatest deflection of helicotrema

• semicircular canals detect rotational (angular) acceleration
• ---ant. canal : head up or down (yes)
• ---post. canal : head up or down to the side (ear to ear)
• ---lat. canal : head side to side (no)
• utricle detects forward and backward acceleration via stereocilia
• saccule detects acceleration up or down via stereocilia

within the ampulla, stereocilia are embedded in gelatinous endolymph. drag of endolymph during movement bends hair cells in opposite direction of movement