Lecture 5

Question 1

Ear - Structures?

Answer 1

-Outer Ear
-Middle Ear
-Inner Ear

Question 2

(Ear - Structures)
Outer Ear?

Answer 2

(receives incoming sound waves)
-Auricle (pinna) –> External Auditory Meatus –> Tympanic membrane (eardrum)
-Lined with stratified squamous epithelium + elastic cartilage
-Ceruminous glands produce ear wax

Question 3

(Ear - Structures)
Middle Ear?

Answer 3

(transmits sounds from outer to inner ear)
-Housed in tympanic cavity
-Lined with simple squamous epithelium (derived from endoderm)
-Auditory (eustachian) tube = ciliated pseudostratified columnar epithelium (connects middle ear to nasopharynx) (helps to change pressure in order to maintain equilibrium)
-Ossicles: malleus –> incus –> stapes –> oval window
-Round window important for rebounding of sound

Question 4

(Ear - Structures)
(Middle Ear)
Auditory (eustachian) tube?

Answer 4

Ciliated pseudostratified columnar epithelium (connects middle ear to nasopharynx) (helps to change pressure in order to maintain equilibrium)

Question 5

(Ear - Structures)
(Middle Ear)
Ossicles?

Answer 5

Malleus –> incus –> stapes –> oval window

Question 6

(Ear - Structures)
(Middle Ear)
Oval Window important for?

Answer 6

Rebounding of sound

Question 7

(Ear - Structures)
(Inner Ear)?

Answer 7

(hearing + balance)
-Bony labyrinth (filled with perilymph) (contains vestibule + semicircular canals + cochlea)
-Membranous labyrinth (filled with endolymph) (contains saccule + utricle + semicircular ducts + cochlear ducts)

Question 8

(Ear - Structures)
(Inner Ear)
Bony Labyrinth?

Answer 8

Filled with perilymph
(contains vestibule + semicircular canals + cochlea)

Question 9

(Ear - Structures)
(Inner Ear)
Membranous Labyrinth?

Answer 9

Filled with endolymph (contains saccule + utricle + semicircular ducts + cochlear ducts)

Question 10

Bony Labyrinth carved out of?

Answer 10

Temporal Bone and contains perilymph (fluid)

Question 11

Bony Labyrinth surrounds?

Answer 11

-Cochlea
-Vestibule (middle portion between cochlea + semicircular canals)
-3 semicircular canals

Question 12

Membranous Labyrinth lines?

Answer 12

Inside of bony labyrinth and contains endolymph (fluid)

Question 13

Membranous Labyrinth surrounds?

Answer 13

-Cochlear duct (inside cochlea)
-Saccule + Utricle (inside vestibule)
-Semicircular ducts (inside semicircular canals)

Question 14

(Membranous Labyrinth surrounds)
Cochlear duct?

Answer 14

(inside cochlea)
-Contains scala media (which houses organ of corti)
-Function is hearing

Question 15

(Membranous Labyrinth surrounds)
Saccule + Utricle?

Answer 15

(inside vestibule)
-Contains maculae
-Function is motion sense (linear acceleration)

Question 16

(Membranous Labyrinth surrounds)
Semicircular ducts?

Answer 16

(inside semicircular canals)
-Contains crista ampullaris
-Function is balance (angular motion)

Question 17

(Inner Ear - Cochlea)
Cochlea is responsible for?

Answer 17

Hearing
(covered by bony labyrinth)
(contains cochlear duct (covered by membranous labyrinth)

Question 18

(Inner Ear - Cochlea)
Cochlea consists of 3 chambers?

Answer 18

-Scala vestibuli
-Scala media
-Scala tympani

Question 19

(Inner Ear - Cochlea)
Cochlea duct?

Answer 19

Scala media (with endolymph)

Question 20

(Inner Ear - Cochlea)
Cochlea duct contains?

Answer 20

-Organ of corti
-Hair cells with stereocilia
-Tectorial membrane
-Basilar membrane

Question 21

(Inner Ear - Cochlea)
(Cochlea duct)
Organ of corti?

Answer 21

Receptor organ for hearing

Question 22

(Inner Ear - Cochlea)
(Cochlea duct)
Hair cells with stereo cilia?

Answer 22

Convert sound to neural impulse

Question 23

(Inner Ear - Cochlea)
(Cochlea duct)
Tectorial membrane?

Answer 23

Attached to hair cells

Question 24

(Inner Ear - Cochlea)
(Cochlea duct)
Basilar membrane?

Answer 24

Supports organ of corti
(generates different sound frequencies (base (narrow portion) of basilar membrane (high pitch)) (apex (wide portion) of basilar membrane (low pitch))

Question 25

(Inner Ear - Cochlea)
Displacement of stereo cilia in the hair cells of tectorial membrane results in?

Answer 25

Generation of APs (ex. neural impulse)

Question 26

(Inner Ear - Sound Transmission)
Steps involved in transmission of sound waves?

Answer 26

1) Sound travels up scala vestibuli –> makes waves in perilymph –> transferred to scala media (endolymph)
2) Waves in endolymph move basilar membrane –> stimulates hair cells –> stereo cilia move against tectorial membrane
3) Sound is turned into APs –> neural impulses

Question 27

(Inner Ear - Sound Transmission)
Excess vibrations travel down?

Answer 27

Scala tympani –> absorbed by round window

Question 28

(Inner Ear - Crista Ampullaris)
Location?

Answer 28

Located in semicircular duct (membranous labyrinth)

Question 29

(Inner Ear - Crista Ampullaris)
Function?

Answer 29

Angular motion (acceleration)

Question 30

(Inner Ear - Crista Ampullaris)
Covered by?

Answer 30

Cupula (gelatinous membrane)
(movement of endolymph in duct displaces cupola –> stimulates hair cells)

Question 31

(Inner Ear - Maculae)
Location?

Answer 31

Saccule + Utricle of Vestibule

Question 32

(Inner Ear - Maculae)
Function?

Answer 32

Gravity + Linear Acceleration

Question 33

(Inner Ear - Maculae)
Covered by?

Answer 33

Otoconia (little crystals –> push down on stereo cilia of hair cells)
(otolithic membrane underlies otoconia)

Question 34

(Inner Ear - Maculae)
Kinocilium?

Answer 34

Microtubules –> interact with stereocilia displaced by otoconia
(movement towards kinocilium opens channels; movement away closes channels)