Liana Machado Ear Section

Question 1

what are sound waves

Answer 1

this is sound that is caused by small areas of high and low pressure propagating outwards from the sources.

Question 2

what are the three parts of the ear

Answer 2

outer
middle
inner

Question 3

what are the parts of the outer ear

Answer 3

pinna
auditory canal

Question 4

what is the pinna

Answer 4

this is the fold of cartlidge-supported skin; captures sound and focuses it into the auditory canal

Question 5

what is the auditory canal

Answer 5

ends at the ear drum

Question 6

what are the parts of the middle ear

Answer 6

ossicles
eardrum

Question 7

what is the ear drum

Answer 7

this is your tympanic membrane, helps in hearing and protecting your middle ear from debris.

Question 8

what are the ossicles

Answer 8

these are the middle ear bones.

Question 9

what is the process in which sound travels through the ossicles

Answer 9

when sound reaches the middle ear, series of high and low pressure regions impinge upon the ear drum
the arrival of these regions cause the eardrum to vibrate.
because the eardrum is attached to the bones in the middle ear, these bones vibrate too.
this sound is transformed into mechanical vibrations that are then transmitted to the fluid in the inner ear via vibrations of the membrane at the oval window.

Question 10

what are the parts of the inner ear

Answer 10

cochlea

Question 11

what is the cochlea

Answer 11

this is a spiral-shaped fluid-filled tube that contains the hair cells that serve as the receptors for audition.

Question 12

what do the hair cells in the cochlea do

Answer 12

they respond by converting the mechanical vibrations into an electrical signal.

Question 13

what do the hair cells in the cochlea synapse onto?

Answer 13

spiral ganglion cells

Question 14

what specific frequency are spiral ganglion cells tuned to

Answer 14

they can be maximally sensitive to a sound of 1600 Hz.

Question 15

what is tinnitus

Answer 15

this is when a person hears noises in the absence of any sound stimuli.

Question 16

when the axons of the spiral ganglion cells exit the cochlea, what do they converge with?

Answer 16

axons of vestibular neurons

Question 17

what to axons of spiral ganglion cells and vestibular neurons form?

Answer 17

the vestibulocochlear nerve

Question 18

what does the vestibulocochlear nerve do

Answer 18

it carries nerve impulses for both balance (vestibular nerve) and hearing (auditory nerve) from the ear to the brain.

Question 19

what happens in the auditory pathway from the cochlea nuclei

Answer 19

auditory information ascends bilaterally to the inferior colliculi (in the midbrain).

Question 20

what do neurons in the superior colliculi do

Answer 20

they synapse on neurons in the medial geniculate nucleus of the thalamus

Question 21

what do the neurons in the medial geniculate nucleus of the thalamus do

Answer 21

these synapse on neurons in primary auditory cortex

Question 22

what is the primary auditory cortex located

Answer 22

in the superior temporal lobe, buried in the lateral sulcus.

Question 23

what is the primary auditory cortex

Answer 23

this is the first region of cortex to process sound

Question 24

what type of map does the primary auditory cortex make

Answer 24

a tonotopic map - through the frequency tuning properties of the cells.

Question 25

what is interaural time

Answer 25

this is the difference in the arrival time of a sound at each ear.

Question 26

what happens at the external ear?

Answer 26

sound waves are captured by the pinna and focused into the auditory canal

Question 27

what happens in the middle ear

Answer 27

sound waves strike the eardrum and vibrations pass through the ossicles to the cochlea

Question 28

what happens in the inner ear

Answer 28

hair cells in the cochlea transduce the vibrations into a neural signal sending it to spiral ganglion cells whose axons form the cochlear nerve. this nerve carries information to the brain stem via the vestibulocochlear nerve.

Question 29

what happens in the brain stem

Answer 29

auditory information is received by the cochlear nuclei (in the pons/medulla) and then is sent bilaterally to the inferior colliculi.

Question 30

what happens in the thalamus

Answer 30

from the inferior colliculi, auditory information is sent to the medial geniculate nucleus (MGN) of the thalamus.

Question 31

what happens in the cortex

Answer 31

from the MGN, auditory information is sent to primary auditory cortex in the superior temporal lobe