Structure Of The Ear

Question 1

What parts comprise the external ear?

Answer 1

The pinna or auricles

The external acoustic meatus

Question 2

What is the function of the auricles?

Answer 2

To direct sound waves into the external acoustic meatus

Question 3

What is the name of the flat triangular prominence of the pinna that partially occludes the entrance to the external acoustic meatus?

Answer 3

Tragus

Question 4

Which part of the auricle does not contain elastic cartilage?

Answer 4

Lobule

Question 5

What are the two kinds of glands present in the external acoustic meatus?

Answer 5

Sebaceous and ceruminous glands

Question 6

What is the function fo cerumen?

Answer 6

To prevent the entrance of foreign particles into the ear and reduce the risk of infection

Question 7

What is the other name for the tympanic cavity?

Answer 7

Middle ear

Question 8

What is the name of the epithelial sheet that separates the external and middle ear?

Answer 8

Tympanic membrane

Question 9

What is the approximate diameter of the tympanic membrane?

Answer 9

1cm

Question 10

Where does the Eustachian tube attach?

Answer 10

The middle ear and the nasopharynx

Question 11

What are the names of the three ossicles in order from most lateral to most medial, of the middle ear?

Answer 11

Malleus
Incus
Stapes

Question 12

What are the names of the two muscles in the inner ear and what is the purpose of these muscles?

Answer 12

Tensor tympani
Stapedius

These dampen the vibrations of the ossicles by contracting in response to high intensity sounds in order to protect the ear from load noises

Question 13

What is the purpose of the pharyngotympanic tube?

Answer 13

To equalise the pressure within the tympanic cavity to the barometric pressure

Question 14

What is the name of the opening between the middle and inner ear which articulates with the footplate of the stapes?

Answer 14

Oval window

Question 15

What are the two major structures of the inner ear?

Answer 15

Vestibule

Cochlea

Question 16

What is the name of the fluid contained within the bony labyrinth?

Answer 16

Perilymph

Question 17

What is the name of the fluid contained within the membranous labyrinth?

Answer 17

Emdolymph

Question 18

What is the name of the central pillar which the cochlea wraps around?

Answer 18

Modiolus

Question 19

The scala vestibuli and scala tympani form part of the membranous labyrinth. T/F?

Answer 19

False - they are part of the bony labyrinth

Question 20

What is the name of the opening which connects to scala vestibuli to the scala tympani?

Answer 20

Helicotrema

Question 21

What is the other name for the cochlear duct?

Answer 21

Scala media

Question 22

The organ of Corti is contained in the scala…?

Answer 22

Media

Question 23

The oval window is contained on the lateral wall of the…?

Answer 23

Vestibule

Question 24

The round window sits at the base of the….

Answer 24

Scala tympani

Question 25

Within the bony vestibule there are two membranous sacs. These are..?

Answer 25

Saccule

Utricle

Question 26

Which cranial nerve is responsible for passing signals from the cochlea to the auditory cortex?

Answer 26

Vestibulocochlear

Question 27

Where is the basilar membrane situated?

Answer 27

Between the scala tympani and scala media

Question 28

Hair cells of the organ of Corti are embedded in the underside of which membrane?

Answer 28

Tectorial membrane

Question 29

Hair cells of the organ of Corti are arranged in a gradient according to their length. T/F?

Answer 29

True

Question 30

What does the stria vadcularis do?

Answer 30

Secretes emdolymph

Question 31

How does resonant frequency change over the length of the basilar membrane?

Answer 31

The end of the membrane at the helicotrema is flexible and heavy and so resonants at low frequencies
The other end of the membrane is stiff and light so resonates at high frequencies