Auditory System

Question 1

Name 1-14

Answer 1

1.lateral border of helix
2.apex
3.scapha
4.medial border of helix
5.spine of helix
6.anthelix
7.lateral crus of helix
8.medial crus of helix
9.pretragic incisure
10.tragus
11.intertragic incisure
12.medial process of antitragus
13.lateral process of antitragus
14.cutaneous marginal pouch

Question 2

Ear gross anatomy

Answer 2

-varies in size and shape between breeds
-highly mobile
-deep ear canal for better hearing (dogs hearing is 4x better than humans) worse for infection

Question 3

Innervation of the ear

Answer 3

-auricular arteries branch from carotid artery follow helical margins
-venous drainages to maxillary vein
-sensation from cranial nerves V (trigeminal) and VII (facial)

Question 4

Name 1-4

Answer 4

1.great auricular artery
2.parotid gland
3.facial nerve (VII)
4.auriculotemporal nerve (V)

Question 5

Properties of sound - frequency

Answer 5

-measures in cycles per second (Hetz: Hz)
-high frequency (15,000Hz)
-low frequency (100Hz)

Question 6

Properties of sound - wavelength

Answer 6

-speed of sound transmission
-indication of medium sound travels through

Question 7

Properties of sound - amplitude

Answer 7

-size of peak or trough
-measured in decibels (dB)
-indication of sound volume

Question 8

Name 1-13

Answer 8

1.malleus
2.incus
3.stapes (attached to oval window)
4.vestibule
5.vestibular nerve
6.cochlear nerve
7.round window
8.cochlea
9.eustachian tube
10.tympanic cavity
11.tympanic membrane
12.ear canal
13.auricle

Question 9

Sound transduction process

Answer 9

1.sound wave represents alternating areas of high and low pressure
2.tympanic membrane vibrates in response to sound wave
3.vibrations are amplified across ossicles
4.vibrations against oval window set to standing wave in fluid of vestibuli
5.pressure bends the membrane of the cochlear duct at a point of a maximum vibration for a given frequency, causing hair cells in the basilar membrane to vibrate

Question 10

Name 1-5 of parts of cochlea

Answer 10

1.organ of Corti
2.basilar membrane
3.scala tympani
4.cochlear duct
5.scala vestibuli

Question 11

Name 1-9 of cochlea close up

Answer 11

1.bony cochlear wall
2.scala vestiubli
3.cochlear duct
4.tectorial membrane
5.basilar membrane
6.scala tympani
7.spiral ganglion
8.cochlear branch of N VIII
9.organ of Corti

Question 12

Name 1-4 of organ of corti in cochlea

Answer 12

1.tectorial membrane
2.tether
3.stereocilia
4.hair cell

Question 13

Name 1-5 of parts involved in sound transduction

Answer 13

1.oval window base
2.tectorial membrane
3.apex
4.basilar membrane
5.round window

Question 14

Name 1-9 of parts of utricle of cochlea

Answer 14

1.macula
2.utricle (cut)
3.saccule
4.endolymph
5.macula
6.otoliths
7.otolithic membrane
8.hair cells
9.vestibular division of vestibulocochlear nerve

Question 15

Name 1-4 of vestibular function of head upright and head tilited forward

Answer 15

1.otolithic membrane
2.otoliths
3.hair cells
4.macula

Question 16

Name 1-3 and explain 4 of vestibular function of head in still position and head rotating

Answer 16

1.ampullary nerve
2.cupula
3.ampulla
4.as the head rotates, cupula bends in opposite direction of the rotation

Question 17

Auditory hair cell transduction

Answer 17

Rapid conversion of mechanical sound vibrations into electrical signals by cochlear hair cells

Question 18

Auditory hair cell transduction process

Answer 18

Sound waves hit tympanic membrane causing it to vibrate
1.sound waves cause vibrations in the cochlea which result in the deflection of stereocilia hair bundles
2.bending the bundle toward the tallest stereocilia increases tension on tip links which causes Ca2+ and K+ channels to open at the tips
3.influx of Ca2+ and K+ depolarises the hair cell, the membrane potential change opens voltage-gated Ca2+ channels, triggering the release of neurotransmitter (glutamate) at the synapse with the auditory nerve

Question 19

Name 1-4 and process that is happening

Answer 19

Auditory hair cell transduction
1.tip link
2.actin
3.stereocilium
4.rootlet

Question 20

Name 1-4 during auditory hair cell transduction

Answer 20

1.voltage-gated calcium channel
2.vesicle filled with excitatory neurotransmitter
3.neurotransmitter
4.afferent nerve

Question 21

Auditory hair cell tuning

Answer 21

The process by which cochlear hair cells selectively respond to specific sound frequencies, essential for frequency discrimination

Question 22

Auditory hair cell tuning - basilar membrane tonotopy

Answer 22

Hair cells at the basal end of the cochlea are tuned to high frequencies (at narrow stiff base) while those at the apical end are tuned to low frequencies (at the wider, more flexible apex)
-hair cells positioned along this membrane and are thus physically ‘pre-filtered’ to receive only the frequencies that cause their specific section of the membrane to vibrate
-specific frequencies for specific hair cells

Question 23

Name 1-9 of auditory hair cell tuning

Answer 23

1.cochlea
2.base
3.hair cells
4.stereocilia
5.apex
6.basilar membrane
7.auditory neuron
8.auditory nerve
9.to cochlear nucleus

Question 24

Neural auditory conduction

Answer 24

Processes by which the nervous system identifies, encodes, and interprets sound waves, transitioning from physical vibration to electrical signals in the cochlea and subsequent processing in the auditory brainstem and cortex

Question 25

Neural auditory detection process

Answer 25

1.sound waves cause vibrations in the tympanic bulla and through the ossicles, create fluid ripples in the cochlea 2.these fluid waves stimulate tiny hair cells (stereocilia) in the organ of Corti. Bending of these cells opens channels, initiating electrical signals 3.resulting action potentials are transmitted to the brain via the cochlear nerve - which is part of the VIIIth cranial nerve (vestibulocochlear nerve)

Question 26

Auditory hair cell transduction v neural auditory detection

Answer 26

Auditory hair cell transduction is the process of converting mechanical sound vibrations into graded electrical potentials within cochlea’s hair cells WHEREAS Neural auditory detection involves translating these graded potentials into action potentials in the auditory nerve for brain processing

Question 27

Name 1-8 of neural auditory detection

Answer 27

1.outer hair cells 2.inner hair cells 3.spiral ganglion cells 4.auditory nerve 5.from superior olivary complex 6.to cochlear nucleus 7.radial fibres 8.outer spiral fibres

Question 28

Name structure and 1-9

Answer 28

Cochlea 1.bony cochlear wall 2.scala vestibuli 3.cochlear duct 4.tectorial membrane 5.basilar membrane 6.scala tympani 7.spiral ganglion 8.cochlear branch of N VIII (Vestibulocohlear) 9.organ of Corti

Question 29

Name 1-5 of system of auditory processing in brain

Answer 29

1.primary auditory cortex 2.medial geniculate 3.inferior colliculus 4.superior olive 5.cochlear nucleus

Question 30

Name 1-6 of system of auditory processing in brain

Answer 30

1.cochlea 2.cochlear nucleus 3.superior olive 4.inferior colliculus 5.medial geniculate body 6.auditory cortex

Question 31

Name 1-8 of primary auditory pathway

Answer 31

1.auditory receiving centers 2.medial geniculate body 3.inferior quadrigeminal body 4.lateral lemniscus 5.olivary nucleus 6.dorsal cochlear nucleus 7.ventral cochlear nucleus 8.Vestibulocohlear nerve

Question 32

The ‘What’ pathway

Answer 32

Cochlear nucleus important for determining what a sound is -maps out tones at higher resolution -then travels up to the auditory nerve and relays map over existing maps of sounds

Question 33

Name 1-6 and what is it?

Answer 33

Cochlear nucleus complex 1.dorsal cochlear nucleus 2.Anteroventral cochlear nucleus 3.cochlear nerve 4.spiral lamina 5.cochlea 6.posteroventral cochlear nucleus

Question 34

How is it figured out where a sound is coming from?

Answer 34

-using binaural input (two-ear hearing) relies on the brain comparing subtle differences in the sound signal as it reaches each ear -maps out frequency and sound and how loud and if heard in one ear, both ears etc. -mapped out through cortex

Question 35

What are otoliths in the utricle of the ear?

Answer 35

Microscopic calcium carbonate crystals (otoconia) embedded within a gelatinous membrane that sits on top of hair cells