Inner Ear

Question 1

Three parts of inner ear

Answer 1

Vestibular division, auditory division, bony labyrinth in petrous portion

Question 2

Promontory

Answer 2

Bony, protect oval and round window

Question 3

Ampullae

Answer 3

Contain sensory receptor organs of SC

Question 4

Responsive to linear acceleration

Answer 4

Utricle and Saccule

Question 5

Cochlear turns

Answer 5

2 and 3/4 turns

Question 6

Central bony canal of cochlea

Answer 6

Modiolus

Question 7

Diameter of cochlea

Answer 7

9 mm

Question 8

Cochlear height

Answer 8

5 mm high

Question 9

Organization of Cochlea (top to bottom)

Answer 9

Scala vestibuli, Reissner’s membrane, Scala media (cochlear duct), Scala Tympani

Question 10

Spiral Lamina

Answer 10

Composed of two plates, osseous

Question 11

Lower shelf of spiral lamina

Answer 11

Supports connection with Basilar membrane

Question 12

Upper shelf of spiral lamina

Answer 12

Continuos with the spiral limbus, serves as an attachment for tectorial membrane

Question 13

Reissner’s membrane

Answer 13

Two layers of epithelial cells

Question 14

Organ of Corti lies…

Answer 14

Lies on top of Basilar membraine

Question 15

Connective tissues consist of…

Answer 15

Intracellular material, collagenous fibers

Question 16

Basilar membrane consists of …

Answer 16

Collagen type II, IV, XI

Question 17

Portions of Basilar membrane

Answer 17

Outer spiral ligament, inner spiral ligament, pectinate and arcuate zone

Question 18

Arcuate zone

Answer 18

vibrates little

Question 19

Pectinate zone

Answer 19

Free to vibrate upon sound induced displacement

Question 20

Basilar membraine length

Answer 20

35 mm

Question 21

BM Thickest at ____

Answer 21

Apex

Question 22

Cochlear duct width at base and apex

Answer 22

Broad near base and narrow towards apex

Question 23

Stiffness ratio of BM

Answer 23

100:1 from base to apex

Question 24

Hensen’s stripe

Answer 24

Underside of Tectorial Membrane, above IHCs

Question 25

IHC function and shape

Answer 25

Transforming of sound, does not vibrate flask-shaped

Question 26

OHC function and shape

Answer 26

increase sensitivity of IHCs, tube shaped

Question 27

Populations of hair cells

Answer 27

3,500 IHCs and 13500 OHCs

Question 28

OHC arrangement

Answer 28

3 rows basal turn, 4 rows middle turn, 5 rows apically

Question 29

Stereocilia arrangement on each OHC

Answer 29

W or V shaped

Question 30

Stereocilia arrangment on each IHC

Answer 30

flat shapped, shallow U

Question 31

How many rows of cilia?

Answer 31

2-3 rows on each cell

Question 32

Positioning of IHCs of BM

Answer 32

Arcuate zone

Question 33

Difference between diameter and length of OHC

Answer 33

Diameter remains constant, length varies

Question 34

Length of OHCs, Diameter?

Answer 34

25 μm basally, 70 μm apically, 7μm

Question 35

Number of stereocilia per OHC

Answer 35

130 in basal, 70 in apical

Question 36

Cell body height of IHC

Answer 36

fairly constant

Question 37

Number of stereocilia per IHC

Answer 37

50-70

Question 38

Outer hair cell links?

Answer 38

Tip links and lateral links

Question 39

Deiter's cells

Answer 39

Rest on BM, cradle bottom of OHCs

Question 40

Fingerlike projections of DCs

Answer 40

Project to surface of organ of corti to hold top of OHC

Question 41

Reticular Lamina

Answer 41

The phalangeal processes, tops of the pillar cells, and cuticular plates of the IHCs and OHC

Question 42

Perilymph

Answer 42

Space between bony and membranous labyrinths (SV and ST)

Question 43

Endolymph

Answer 43

Membranous labyrinth (Scala Media)

Question 44

Scala media communicates at..

Answer 44

Basal Region with saccule at ductus reuniens

Question 45

Endolymphatic sac

Answer 45

Regulates endolympth pressure

Question 46

Reissner's membrane attached to outer wall by...

Answer 46

Spiral Ligament

Question 47

Cochlear Aqueduct

Answer 47

Runs parallel to Internal Auditory Meatus, allows transfer of Cerebrospinal fluid