The Ear

Question 1

What is the external acoustic meatus

Answer 1

A sigmoid shaped tube that extends from the deep part of the concha to the tympanic membrane

Question 2

What are the external 1/3 of the ear formed by

Answer 2

Cartilage

Question 3

What is the inner 2/3 of the ear formed by

Answer 3

The temporal bone

Question 4

What is the middle ear filled with

Answer 4

Air

Question 5

Where does the tympanic membrane lie

Answer 5

At the distal end of the external acoustic meatus

Question 6

What is the tympanic membrane

Answer 6

Connective tissue structure covered with skin on the outside and a mucous membrane on the inside
The membrane is connected to the surrounding temporal bone by a Fibrocartilaginous ring

Question 7

Is the tympanic membrane translucent

Answer 7

Yes

Question 8

What do compression waves in the air (sound waves) cause in the ear

Answer 8

The tympanic membrane to vibrate which is amplified and transmitted by the ossicles to the oval window

Question 9

What are the 3 ossicles

Answer 9

Malleus
Incus
Stapes

Question 10

What happens once a vibrations has reached the oval window

Answer 10

They are converted into waves in the perilymph fluid of the inner ear

Question 11

What is the innervation of the stapedius

Answer 11

A branch of the facial nerve (nerve to stapedius)

Question 12

What does the tensor tympani in the ear do

Answer 12

Pulls the manubrium of the malleus medially tensing the tympanic membrane and dampening movement in response to loud noises

Question 13

What is the innervation of the tensor tympani in the ear

Answer 13

By a branch of the mandibular division of the trigeminal nerve

Question 14

What type of epithelium is the pharyngotympanic tube

Answer 14

Ciliated columnar epithelium

Question 15

What 3 parts of the ear are housed in the temporal bone

Answer 15

Cochlea
Vestibule
Semicircular canals

Question 16

What are the 3 parts of the bony labyrinth

Answer 16

Vestibule
Cochlea
Semilunar canals

Question 17

What is the endolymph

Answer 17

Clear potassium rich fluid filling the membranous labyrinth

Question 18

What is the membranous labyrinth

Answer 18

Utricle and saccule inside the vestibule, cochlear duct and membranous semicircular ducts

Question 19

What is the perilymph

Answer 19

Surrounds the membranous labyrinth filling the space between the membranous tunnel and its contents and the bony walls that surround it

Question 20

What is the modiolus

Answer 20

Cone shaped core of bone that houses the spiral ganglion which consists of cell bodies of the first sensory neurons in the auditory relay

Question 21

What does the cochlear duct contain

Answer 21

Endolymph

Question 22

What is the upper section of the cochlea called

Answer 22

The scala vestibuli

Question 23

What is the lower section of the cochlea called

Answer 23

Scala tympani

Question 24

Where does the cochlea divide into two sections

Answer 24

In the cochlear duct which is inside the cochlea

Question 25

What are both sections of the cochlea filled with

Answer 25

Perilymph

Question 26

What part of the basilar membrane deals with high frequency sound waves

Answer 26

They vibrate the narrow portion near the oval window

Question 27

Which part of the basilar membrane deals with low frequencies

Answer 27

The wider, thicker portion near the apex of the cochlea

Question 28

What is stimulated for hearing to occur

Answer 28

The auditory area of the cerebral cortex

Question 29

What is the pathway of sound waves

Answer 29

Enter external auditory canal
Strike tympanic membrane causing vibrations
Tympanic vibrations move the malleus which in turn moves the incus and then the stapes
The stapes moves against the oval window which begins the fluid conduction of sound waves

Question 30

What do the hair cells in the ear do

Answer 30

Move against the tectorial membrane stimulating the dendrites that terminate around the base of the hair cells and initiates impulse conduction by the cochlear nerve to the brain stem

Question 31

What do impulses for hearing pass through before reaching the temporal lobe

Answer 31

Relay station in the nuclei in the medulla, pons, midbrain and thalamus before reaching the auditory area o f the temporal lobe

Question 32

What is the vestibule

Answer 32

The central section of the bony labyrinth the utricle and saccule are the membranous structures within the vestibule

Question 33

How many semicircular canals are there found in the temporal bone

Answer 33

3

Question 34

What do each semicircular canal contain and connect with

Answer 34

Contain endolymph and connects with the utricle

Question 35

How does sense of balance occur

Answer 35

Movements of the maculae located in both the utricle and saccule provide information related to head position or acceleration

Question 36

Where are otoliths located

Answer 36

Within the matrix of the macula

Question 37

What causes the cupula to lean in the opposite direction

Answer 37

As the endolymph is not attached to the skull it does not move immediately leading to tension in the tip links causing mechanical opening or closing of ion channels leading to the influx of ions terminating in the propagation of impulses along the vestibular branch of the vestibulocochlear nerve

Question 38

How do the impulses travel

Answer 38

To the vestibular nucleus and from there to the cerebellum

Question 39

Which parts of the ear are mainly responsible for forward/backward and up/down motion detection

Answer 39

The utricle and saccule in the vestibule

Question 40

How does your ear detect motion and fix it

Answer 40

Fluid in semicircular canals shift the tiny hairs triggering activity in vestibule which are connected by sacs called saccule and utricle which also contain tiny hairs to sense movement
Therefore semicircular canals and vestibule let your brain know about the movement

Question 41

What are the 3 nerves which go to the ear

Answer 41

Facial
Vestibular nerve
Auditory nerve