Exam #2: Ear

Question 1

Where is the internal ear located?

Answer 1

Petrous portion of the temporal bone

Question 2

External Acoustic Meatus, bone vs. cartilage

Answer 2

• Lateral 1/3 is cartilage

- Medial 2/3 is bone (temporal)

Question 3

What are the three layers of the TM?

Answer 3

1) External
2) Intermediate
3) Internal Surface

Question 4

External Layer of the TM

Answer 4

• Thin epidermis

- Stratified squamous epithelium

Question 5

Intermediate Layer of the TM

Answer 5

• Collagen, elastic fibers & fibroblasts

- Fibroblasts function in regeneration of the TM

Question 6

Internal Surface of the TM

Answer 6

Simple cuboidal to simple squamous epithelium

Question 7

What cell type lines the ossicles?

Answer 7

Simple squamous epithelium

Question 8

Malleus

Answer 8

• Tensor Tympani Muscle
• CN V
• Function: to dampen loud sounds

Question 9

Stapes

Answer 9

• Stapidus Muscle
• CN VII
• Function: to dampen loud sounds

Question 10

What type of epithelium lines the Eustachian/ auditory tube?

Answer 10

• Remember: extension from the ear into the nasopharyx that takes on a respiratory epithelium
• Pseudostratified columnar epithelium with goblet cells

Question 11

Bony Labyrinth

Answer 11

Perilymph

Question 12

Membranous Labyrinth

Answer 12

Endolymph

Question 13

Cortilymphatic Space

Answer 13

• Intercellular space in the Organ of Corti

- Perilymph-like composition

Question 14

What is the cochlea coiled around?

Answer 14

Mediolus

Question 15

Cochlea

Answer 15

Sound

Question 16

Vestibule

Answer 16

• Space between the cochlea & semicircular canals
• Linear movement
• Saccule & Utricle

Question 17

Semicircular Canals

Answer 17

• Rotational/ angular movement

- Amuplla region contains hair cells

Question 18

Ampulla

Answer 18

• Swelling in the semicircular canals as they attach to the vestibule, which contains hair cells

Question 19

Which part of the inner ear contains the oval window, and which contains the round window?

Answer 19

• Oval window= vestibule

- Round window= cochlea

Question 20

Perilymph

Answer 20

• Bony Labyrinth
• ECF
• High Na+, Low K+

Question 21

Endolymph

Answer 21

• Membranous Labyrinth
• ICF
• High K+, Low Na+

Question 22

Crista Ampullaris

Answer 22

• Sensory part of semicircular canals

- Rotational/ Angular movement

Question 23

Spiral Organ of Corti

Answer 23

Contains hair cells in the cochlea for hearing

Question 24

Movement Hair Cells: Type I vs. Type II

Answer 24

• Type I= afferent neuron surrounds entire cell

- Type II= afferent neuron sits only at the base

Question 25

Kinocilia

Answer 25

- Large pole region of cell | - Cilia structure

Question 26

Stereocilia

Answer 26

- Smaller projects of the apex of the hair cell adjacent to kinocilia - Specializations of the plasma membrane

Question 27

What can increased pressure in the endolymph cause?

Answer 27

- Accidental stimulation of the hair cells - Vertigo - Tinnitus

Question 28

Cupula

Answer 28

- Gelatinous substance in the crista ampullaris that the hair cells imbed into - NO Otoliths associated - Type I & Type II hair cells

Question 29

Macula

Answer 29

- Region of the utricle & saccule that contains sensory receptors - Linear movement - Otoliths

Question 30

What type of movement does the utricle sense?

Answer 30

Horizontal

Question 31

What they of movement does the saccule sense?

Answer 31

Vertical

Question 32

Three compartments of the cochlea (top-->bottom)

Answer 32

1) Scala Vestibule (Perilymph) 2) Scala Media (Endolymph) 3) Scala Tympani (Perilymph)

Question 33

Helicotrema

Answer 33

apex of the cochlear duct/ scala media

Question 34

Vestibular Membrane (Reissner's Membrane)

Answer 34

- Divides the Scala Vestibule from the Scala Media - Two layers of squamous epithelium - Tight junctions to maintain ion concentrations

Question 35

Scala Vascularis

Answer 35

- Produces endolymph in the Scala Media | - Located on the lateral/outer wall

Question 36

Basilar Membrane

Answer 36

- Divides the Scala Media & Scala Tympani | - Organ of Corti sits ontop

Question 37

Phalangeal Cells

Answer 37

- Support the hair cells in the Organ of Corti | - Form the outer & inner tunnels that contain cortilymph

Question 38

Pillar Cells

Answer 38

Structural cells in the Organ of Corti

Question 39

Tectorial Membrane

Answer 39

- Where hair cells imbed in the Organ of Corti - Contains Type II, V, & IX Collagen - Contains Otogelin & Tectorin, glycoproteins

Question 40

How are the hair cells of the Organ of Corti different from the other parts of the inner ear?

Answer 40

- No kinocilium | - Stereocilia are all the same length/ symmetrical

Question 41

What is the difference between an inner & outer phalangeal cell?

Answer 41

``` Inner= encompass the entire hair cell Outer= do NOT encompass the entire hair cell ```

Question 42

Vestibular Ganglion

Answer 42

Located in the internal auditory meatus

Question 43

Cochlear Ganglion

Answer 43

Located in the Cochlea

Question 44

Which end of the basilar membrane is responsible for high pitched sounds?

Answer 44

Base