Hearing Flashcards
decibles
measure of sound intensity
Frequency
number of sound wave cycles per second
External ear
captures, focuses, and filters sound
Pinna
ear canal
Middle ear
concentrates sound energies
tympanic membrane
Ossicles
tympanic membrane
eardrum
ossicles
Bones:
malleus
Incus
Stapes
Focus vibrations of the tympanic membrane onto the oral window
Muscles attached to ossicles
tensor tympani(stapedius)
Internal Ear
auditory portion(cochlea)
3 parallel canals filled with fluid
tympanic canal, middle canal, vestibular canal
Basilar membrane
flexible; separates tympanic from middle canal
Organ of Corti
elements that transduce sounds
Hair cells
transmit acoustic stimulation
stereocilia
small stiff hairs that extend from the top of hair cells
tectorial membrane
lies on top of organ Corti; stereocilia extend into it
Steps of Conduction of Sound
- sounds vibrate the eardrum
- the vibrations pass along the ossicles to the oval window
- causing the basilar membrane to vibrate
- the hair cells in the basilar membrane move, causing the stiff stereocilia to bend and depolarize
4a. when cilia bend, a link between the cilia is distorted, opening a trapdoor to ion channels
4b. K+ rushes in depolarizing the cell
4c. this initial depolarization opens voltage-gated Ca2+ channels at base of hair cell
4d. synaptic vesicles fuse, the neurotransmitter is released
Tip Link
link between cilia
Auditory Pathway
8th cranial nerve—> cochlear nuclei-> superior olivary nuclei-> inferior colliculus-> medial geniculate-> auditory cortex
Binaural detection
locating position of a sound source using both ears, relies on differences between the stimuli that reach ears
Intensity differences
differences in sound intensity at the two ears
Latency Difference
difference in sound arrival time at the two ears
ACx
analyzes complex sounds
Dorsal stream
determines the where of stimulus
Ventral stream
determines the what of stimulus
conduction
disorder of outer or middle ear
