Special Senses Lecture 3

Question 1

What are the 3 Ossicles?

Answer 1

Malleus, Incus, and Stapes

Question 2

How does Cerumen protect the ear?

Answer 2

It has a bactericidal effect on some strains of bacteria due to presence of fatty acids, lysozyme and its acidity

Question 3

How do hairs in the external auditory meatus protect a person?

Answer 3

They alert the individual when move by invaders to take steps to remove it

Question 4

What does the Pinna do?

Answer 4

Funnels sound into the external auditory meatus

Question 5

What does the External Auditory Meatus do?

Answer 5

Gathers sound energy and focuses it on the tympanic membrane which increases sound energy

Question 6

What is the middle ear filled with?

Answer 6

Air

Question 7

What is the major function of the Middle ear?

Answer 7

Match relatively low impedance airborne sounds to the higher impedance fluid of the inner ear

Question 8

What are the two ways that sound is boosted by the middle ear?

Answer 8

• A differential of a large diameter tympanic membrane to a smaller diameter oval window
• Lever action of the ossicles

Question 9

What does the Eustachian tube do?

Answer 9

Connects the middle ear to the pharynx to allow for the equalization of pressure

Question 10

What are the muscles of the middle ear?

Answer 10

• Tensor tympani

* Stapedius muscle

Question 11

What does the Tensor Tympani attach to?

Answer 11

The malleus and the eustachian tube

Question 12

What does the Stapedius attach to?

Answer 12

The wall of the middle ear and neck of stapes near the articulation with the incus

Question 13

What is the role of the Tensor Tympani and the Stapedius muscle?

Answer 13

Dampen the vibration of the ossicles

Question 14

What are the Semicircular canals involved in?

Answer 14

Balance

Question 15

What occurs in the cochlea?

Answer 15

Sound is processed

Question 16

What is the inner ear composed of?

Answer 16

The cochlea

Question 17

How many turns does the cochlea have?

Answer 17

2.75

Question 18

From top to bottom what are the spaces of the cochlea?

Answer 18

• Scala Vestibuli
• Cochlear duct
• Scala Timpani

Question 19

What is the top compartment of the Cochlea?

Answer 19

Scala Vestibuli

Question 20

What is the middle component of the Cochlea?

Answer 20

The Cochlear duct

Question 21

What is the bottom compartment of the Cochlea?

Answer 21

The Scala Tympani

Question 22

Which components of the Cochlea are filled with Perilymph?

Answer 22

Scala vestibuli and Scala Tympani

Question 23

What is the Cochlear duct/ Scala media filled with?

Answer 23

Endolymph

Question 24

What separates the Scala Vestibuli and the Cochlear duct?

Answer 24

Reissner’s membrane

Question 25

What does Reissner’s membrane separate?

Answer 25

Scala vestibuli and Cochlear duct

Question 26

What does the Basilar membrane separate?

Answer 26

The cochlear duct and the Scala Tympani

Question 27

What separates the Cochlear duct and the Scala Timpani?

Answer 27

The Basilar Membrane

Question 28

What in the cochlea are one tube joined?

Answer 28

The Scala vestibuli and scala tympani

Question 29

How are the Scala Vestibuli and Scala tympani joined?

Answer 29

With the Helicotrema

Question 30

Where does the Organ of Corti rest?

Answer 30

On the Basilar Membrane

Question 31

What do the inner hair cells do?

Answer 31

Encode for sound

Question 32

What do the Outer hair cells do?

Answer 32

Help with sound frequency analysis, motor function

Question 33

How many rows of outer hair cells are there?

Answer 33

3 rows

Question 34

What do all hair cells have on top?

Answer 34

Stereocilia

Question 35

What are Stereocilia?

Answer 35

Hair like bristles of varying length with the shortest in front and tallest in back on top of hair cells

Question 36

What are Stereocilia attached to?

Answer 36

The Tectorial membrane

Question 37

Where does the Tectorial Membrane sit?

Answer 37

On top of the stereocilia of hair cells

Question 38

Which ion is the endolymph saturates with?

Answer 38

Potassium

Question 39

What occurs during mechanical stimulation of the hair bundle?

Answer 39

Potassium ions from the endolymph depolarize the cell when the hair tips and tip links open creating action potentials

Question 40

Where do high frequencies cause maximal dispacement?

Answer 40

Near the stapes

Question 41

Where do low frequencies cause maximal displacement?

Answer 41

Near the apex

Question 42

What is the function of the Round Window?

Answer 42

Dissipate sound energy