Auditory System

Question 1

What makes up the external ear?

Answer 1

Auricle, external auditory meatus, tympanic membrane

Question 2

What is the composition of the tympanic membrane

Answer 2

1.skin of the external
acoustic meatus
2.connective tissue with a
core of radially and
circularly arranged collagen
fibers
3.mucous membrane of the
middle ear

Question 3

What makes up the inner ear?

Answer 3

Ossicles, middle ear cavity, oval and round window, tensor tympani and stapedius muscles

Question 4

What makes up the inner ear and what’s its job?

Answer 4

Scala vestibuli, scala typani, scala media
Transforms sound to electric signals

Question 5

What is at the center of the cochlea?

Answer 5

Boney modiolus containing the perikarya of the spiral ganglion(G).

Question 6

The center of each turn is the:

Answer 6

membranous cochlear duct (scala media, SM) separating scala vestibuli (SV) from scala tympani (ST).

Question 7

What is the apex of the boney cochlea called? What is it?

Answer 7

Helicotrema
Location where the membranous duct ends and the scala vestibuli and scala tympani become continuous with the H

Question 8

What is the cochlear duct?

Answer 8

Separates the scala vestibuli (SV) from the scala media (SM) is the vestibular membrane (VM).

Question 9

What separates the scala media from the scala tympani?

Answer 9

Basilar membrane

Question 10

Resting on the basilar membrane
and projecting into the scala media is the

Answer 10

organ of Corti (OC)

Question 11

What is the organ of corti?

Answer 11

a sensory epithelium located within the cochlea of the inner ear, responsible for converting sound vibrations into electrical signals that are then transmitted to the brain as sound perception
3 outer hair cells, one inner hair cell

Question 12

That do phalangeal support cells do?

Answer 12

Help stiffen the superior surface of the OC

Question 13

What happens when Stereocilia are deflected away from longer stereocilia?

Answer 13

Hair membrane is hyper polarized
Afferent nerve fibers of spiral ganglion neurons are NOT stimulated

Question 14

What happens when Stereocilia deflected towards
longer stereocilia

Answer 14

• Influx of K+ ions
• Hair cell membrane depolarizes
• Influx of Ca2+ ions
• Neurotransmitters are released
• Afferent nerve fibers of spiral ganglion neurons are stimulated (excitation)

Question 15

What occurs with frequency and tone in the organ of corgi?

Answer 15

Tonotopic localization
Higher frequencies detected closer to ear
Lower tones detected closer to helicotrema
(Complex sounds find themselves somewhere in the middle)

Question 16

Axons excited by hair cells travel via CN ______ to _______

Answer 16

cranial nerve 8 (Cochlear division) into the medulla

Question 17

Where do cochlear axons synapses?

Answer 17

Cochlear axons synapse on the ventral and dorsal cochlear nuclei.

Question 18

Unilateral lesions to which CN or nuclei can cause hearing loss and to which side

Answer 18

Unilateral lesions of nerve or cochlear nuclei can
cause hearing loss- ipsilateral ear

Question 19

Since there are bilateral projections at multiple sites in brainstem, unilateral lesions in brainstem beyond cochlear nuclei do NOT produce ____.

Answer 19

deafness

Question 20

FINISH