Chapter 2.3

Question 1

Describe the order in which the ossicles act

Answer 1

• the malleus is affixed to the tympanic membrane
• it then acts on the incus
• finally, the incus acts on the stapes
• the stapes then acts on the oval window of the cochlea

Question 2

How is the middle ear connected to the nasal cavity? What is the role of this connection

Answer 2

• the middle ear is connected to the nasal cavity via the Eustachian tube
• > this helps equalize the pressure between the middle ear and the environment

Question 3

Where does the inner ear sit? What does it contain? Are these structures continuous with each other and what are they filled with?

Answer 3

• it sits within a bony labyrinth
• contains the cochlea, vestibule and semicircular canals
• these structures are mostly continuous with each other
• > they are filled with membranous labyrinth

Question 4

What fluid is the membrane labyrinth bathed with

Answer 4

-it is bathed with endolymph

Question 5

What fluid is the membrane labyrinth suspend in the bone labyrinth with? What does this fluid do for the ear?

Answer 5

-it is suspended within the bony labyrinth by a perilymph fluid

• perilymph transmits vibrations from the outside world
• > cushions the inner ear structures

Question 6

How many parts is the cochlea divided into? What are these parts referred to as?

Answer 6

• divided into three parts

- >or scalae

Question 7

Which scalae houses the organ of corti

Answer 7

• the middle scala houses the organ of corti
• > the organ of corti sits on the basilar membrane
• > it is bathed with perilymph fluid

Question 8

What are the functions of the other two scalae that do not house the organ of corti

Answer 8

• they are continuous with the oval and round window

- >vibrations from the oval window are transmitted to the basilar membrane

Question 9

What two structures do the vestibule contain? What kind of acceleration are these two structures sensitive to?

Answer 9

• it contains the utricle and saccule
• they are sensitive to linear acceleration
• > they are used to determine one’s own orientation in three dimensional space

Question 10

What kind of acceleration are semicircular canals sensitive to? How are semicircular canals arranged in relation to each other?

Answer 10

• they are sensitive to rotational acceleration
• they arranged perpendicularly in relation to each other
• > each ends up in a swelling called the ampulla

Question 11

What is the superior olive involved in

Answer 11

-it localizes the sound

Question 12

What is the inferior colliculus involved in

Answer 12

• it is a startle reflex

- >keeps the eyes fixed on a point while the head is turned

Question 13

What does the place theory state about high frequencies and low frequencies

Answer 13

• high frequencies causes vibrations of the basilar membrane close to the oval window
• low frequencies causes vibrations at the apex
• > away from the oval window

Question 14

Is the cochlea tonotopically organized?

Answer 14

-yes