Anatomy of the Inner Ear and Cochlea

Question 1

inner ear versus the labyrinths

Answer 1

same thing

Question 2

houses sensory ends organs of auditory and vestibular systems

Answer 2

inner ear

Question 3

where are the labyrinths located

Answer 3

petrous portion of the temporal bone

Question 4

anatomy of the inner ear is dominated by large fluid filled spaces which are essential for ________

Answer 4

signal transduction

Question 5

what 2 primary components can the labyrinths be split into

Answer 5

1) bony labyrinth
2) membranous labyrinth

Question 6

vestibule
cochlea
semicircular canals
- post., sup., lat. (horizontal)

Answer 6

bony labyrinth

Question 7

maculae
utricle
saccule
cochlear duct
semicircular ducts
- post.,sup.,lat. (horizontal)
endolymphatic duct/sac

Answer 7

membranous labyrinth

Question 8

what does bony labyrinth contain

Answer 8

perilymph

Question 9

what does a membranous labyrinth contain

Answer 9

endolymph

Question 10

typical extracellular fluid that is high in Na+ and continuous with CSF in subarachnoid space

Answer 10

perilymph

Question 11

very atypical extracellular fluid that is high in K+ and has varying compositions throughout membranous labyrinth (result of K+ pumps) and communicates w/ venous structures of dura mater

Answer 11

endolymph

Question 12

______ results from different compositions of perilymph and endolymph

Answer 12

endocochlear potential

Question 13

endocochlear potential primary consists of ____ ions

Answer 13

K+

Question 14

endolymphatic potential is approx. what at cochlea and varies through endolymphatic space

Answer 14

+85 mV

Question 15

endocochlear potential provides the basis for _________ in sensory hair cells

Answer 15

signal transduction

Question 16

resting membrane potential

Answer 16

-50mV

Question 17

what are the two forces that endocochlear potential results from

Answer 17

1) active addition of K+ into endolymph
2) passive removal of K+ from hair cells

Question 18

what is the oval shaped central portion of the bony labyrinth

Answer 18

vestibule

Question 19

what communicates with cochlea, SCC, and middle ear space

Answer 19

vestibule in bony labyrinth

Question 20

what receives incoming sound stimulus energy from the ME via the OW and dissipates that energy via RW

Answer 20

vestibule in bony labyrinth

Question 21

what is the snail-shaped bony canal with a central bony axis called modiolus

Answer 21

cochlea in bony labyrinth

Question 22

where does the association with the cochlear duct create 3 separate spaces or scale on cross section of the spiral

Answer 22

cochlea in bony labyrinth

Question 23

what is elliptical in shape in the membranous labyrinth

Answer 23

utricle

Question 24

what is connected to saccule via utriculosaccular duct and has a sensory epithelium called a macula

Answer 24

utricle in the membranous labyrinth

Question 25

what has otolithic membranes that overlies macula to facilitate sterociliary deflection

Answer 25

utricle in the membranous labyrinth

Question 26

what labyrinth is globular in shape and has the macula oriented in vertical plane

Answer 26

saccule in the membranous labyrinth

Question 27

what is the scala media another name for

Answer 27

cochlear duct

Question 28

what does the cochlear duct or scale media contain

Answer 28

sensory epithelium of the cochlea

Question 29

what do semicircular ducts do

Answer 29

communicate with utricle and has dilation at one end called ampulla and contains crista ampullaris with a gel-like cupla over the crista ampullaris

Question 30

what originates from the utriculosaccular duct

Answer 30

endolymphatic duct/sac

Question 31

what is the site of endolymph removal to venous drainage

Answer 31

endolymphatic duct/sac

Question 32

what fluid is found within the membranous labyrinth

Answer 32

endolymph

Question 33

what tissue is responsible for special composition of endolymph

Answer 33

stria vascularis

Question 34

where is the stria vascularis tissue located?

Answer 34

lining the lateral wall of the cochlear duct

Question 35

________ can excess endolymph and be released and it [does/does not] imply that there is a natural "flow" of endolymph through the membranous labyrinth

Answer 35

stria vascularis; does

Question 36

what are the inner ear structures that house sensory epithelia

Answer 36

organ of corti (1) saccule (1) utricle (1 for each) ampulla

Question 37

CN VIII (vestibulocochlear nerve) and the CN VII (facial nerve)

Answer 37

the structures that pass through the internal auditory meatus

Question 38

the organ of Corti

Answer 38