Ear Flashcards
Pinna
Outer ear
Channel and funnel for sound
Auditory canal
Carry’s sound to eardrum
Tympanum
Eardrum
Vibrations= sound waves striking (sound energy is transferred here as mechanical energy)
Ossicles
Transmit vibrations from eardrum to oval window
Malleus (hammer
Ancus (anvil)
Stapes (stirrup) strike oval window
What causes amplification of sound
Oval window area>eardrum
Oval window
Vibrations of stapes go to inner ear
Why does sound need to be amplified
Inner ear is fluid fuild so if it wasn’t amplified it would be hard to move
Cochlea and organ of corti
Convert vibrations to neural signal
Stapes movement of oval window moves fluid here
Organ of corti- tectorial membrane basilar membrane and specialized cilia
Round window
End of cochlea
Vibrates in opposite direction of oval window to reduce pressure
How does hearing work
Vibrations from oval winded into cochlea= action potential (selective) and resonate w hair bundles
Why is Action potential selective
Allows for pitch differentiation
Pitch
Close to oval window, basilar membrane is narrow and stiff= vibrated by high frequency
Farther down it’s wide and flexible = lower frequency
Volume
Amplitude increases w volume
Louder noise increases pressure on hair
Auditory nerve
Sends impulse to brain
How does impluses get sent to brain
Cochlea hair depolarize vibrations= neurotm releases= stimulated next sensory neuron= AP in auditory nerve
Static equilibrium
Controlled by vestibule
Filled w jelly which have otiliths (CaCO3 crystals that move when head moves)
Gravity pulls otiliths causing cilia to bend= stimulates sensory neuron and impulse is sent to cerebellum
Dynamic movement
I’m ampulla (pocket) of each semicircular canal is cupua (jelly w cilia)
Rotation cause fluid to move-= cupulla and cilia to bend generating a nerve impulse
