Ear and auditory apparatus

Question 1

What are the three parts of the temporal bone?

Answer 1

squamous
tympanic
petrous

Question 2

The thin scale-like region of the temporal bone? What are the important landmarks on this part?

Answer 2

Squamous part has zygomatic process that contributes to the zygomatic arch and includes the mandibular fossa and articular tubercle of TMJ, inferiorly.

Question 3

Which part of the temporal bone helps form the borders of external auditory meatus?

Answer 3

tympanic part

Question 4

What is the largest part of the temporal bone? What important landmarks are on this part?

Answer 4

petrous part of the temporal bone has the mastoid process, styloid process and internal auditory meatus

Question 5

The mastoid process is the attachment site for which muscles?

Answer 5

SCM
Splenius capitis
posterior belly of digastric

Question 6

The internal auditory meatus connects to which cranial fossa? What passes through it

Answer 6

posterior cranial fossa

CN 7 and 8 pass through it (facial and vestibulocochlear nerve)

Question 7

The styloid process is the attachment site for which muscles?

Answer 7

stylohyoid
styloglossus
stylopharyngeus

Question 8

The styloid process is the attachment site for which ligaments?

Answer 8

stylohyoid

stylomandibular

Question 9

What encloses, stabilizes and preserves the orientation the elements of the inner ear?

Answer 9

the petrous part of the temporal bone

Question 10

The inner ear consists of 2 parts. What are they?

Answer 10

osseous labyrinth

membranous layrinth

Question 11

What is the osseous labyrinth?

Answer 11

a network of bony canals in the inner ear

Question 12

What is the membranous labyrinth?

Answer 12

a network of membranous canals enclosed within the osseous labyrinth of the inner ear

Question 13

What are the elements of the auditory apparatus?

Answer 13

external ear
tympanic membrane
tympanic cavity/middle ear
inner ear

Question 14

The portion of the external ear that functions to collect and funnel sound waves?

Answer 14

auricle or pinna

Question 15

The osseous opening in the temporal bone that divides the external and middle ear?

Answer 15

External auditory meatus

Question 16

The thin, transparent membrane that serves as a partition between the external auditory canal and the middle ear cavity?

Answer 16

tympanic membrane

Question 17

What is the shape of the tympanic membrane and how is it oriented?

Answer 17

It is oval (11mm tall and 9 mm wide) and oriented obliquely to the vertical plane with inferior edge more medial

Question 18

What causes the tympanic membrane to oscillate?

Answer 18

air and bone conduction

Question 19

What nerves share general sensory innervation to the tympanic membrane?

Answer 19

V3 is the major contribution but CN 9 (glossopharyngeal) and CN 10 (vagus) also contribute

Question 20

What supplies blood to the tympanic membrane?

Answer 20

maxillary artery

posterior auricular artery

Question 21

What appears as a streak from the superior edge towards the middle of the tympanic membrane?

Answer 21

the manubrium of the malleus

Question 22

What is the central portion of the tympanic membrane?

Answer 22

umbo

Question 23

What does the umbo correspond to?

Answer 23

the tip of the manubrium

Question 24

The part of the tympanic membrane that is taut?

Answer 24

pars tensa

Question 25

The part of the tympanic membrane that is lax/slack along superior aspect?

Answer 25

pars flaccida

Question 26

Light from otoscope reflects off the tympanic membrane back to the examiners eye. What is this reflection called and where on the tympanic membrane is it located?

Answer 26

cone of light is located on the anterioinferior portion of tympanic membrane

Question 27

Another name for the middle ear?

Answer 27

tympanic cavity

Question 28

In what bone structure is the middle ear enclosed?

Answer 28

petrous part of temporal bone

Question 29

The middle ear is lined by what?

Answer 29

mucosa

Question 30

The Eustachian tube exits the middle ear and passes to the nasopharynx at the ostium of the Eustachian tube. The first 1/3 of the tube's length is formed by _____ and the next 2/3 of the tube's length is formed by _____.

Answer 30

bone | hyaline cartilage

Question 31

As the Eustachian tube exits the middle ear, does it widen or narrow as it passes to the nasopharynx?

Answer 31

widens

Question 32

What are the two primary functions of the Eustachian tube?

Answer 32

- drain secretions out of middle ear | - equalize pressure of middle ear and external pressure

Question 33

What is the space posterior to the tympanic cavity and superior to and continuous with the mastoid air cells? What is is lined with?

Answer 33

mastoid antrum lined with mucosa

Question 34

The largest ear ossicle that is shaped like a hammer and attached to the tympanic membrane?

Answer 34

malleus

Question 35

The ear ossicle that is shaped like an anvil?

Answer 35

incus

Question 36

The ear ossicle that is shaped like a stirrup?

Answer 36

stapes

Question 37

What part of the malleus articulates with the incus?

Answer 37

the head

Question 38

What are the parts/projections of the malleus? What articulates with the tympanic membrane? What articulates with the incus

Answer 38

anterior process lateral process (articulates with tympanic membrane) manubrium process (articulates with tympanic membrane, tensor tympani attaches here) head (articulates with body of incus)

Question 39

What are the parts/projections of the incus? Which articulates with the stapes? What articulates with the malleus?

Answer 39

``` short process long process (articulates with head of stapes) body (articulates with head of the malleus) ```

Question 40

What are the parts/projections of the stapes? What articulates with the incus? What articulates with the oval window of inner ear?

Answer 40

head (articulates with long process of incus) neck (stapedius muscle attaches here) crura (paired legs) base/footplate (articulates with oval window inner ear)

Question 41

What is the function of the middle ear ossicles?

Answer 41

to couple vibrations of the tympanic membrane to movements of the footplate of stapes which cause pressure changes in fluid of inner ear to produce sound

Question 42

Articulations between ear ossicles are what kind of joints?

Answer 42

synovial

Question 43

What are the functions of the labyrinths in the inner ear?

Answer 43

``` auditory reception vestibular reception (balance) ```

Question 44

What are the three parts of the osseous labyrinth?

Answer 44

- vestibule - cochlea - semicircular canals

Question 45

What are the two openings from the inner ear vestibule to the middle ear? What covers each of them?

Answer 45

oval window covered by footplate of stapes | round window covered by secondary tympanic membrane

Question 46

What are the dilations at one end of each semicircular canal?

Answer 46

ampullae

Question 47

How many turns does the cochlea make around its central axis?

Answer 47

2.75

Question 48

The osseous labyrinth is filled with what?

Answer 48

perilymph

Question 49

The membranous labyrinth is suspended in the osseous labyrinth and filled with what? What surrounds the ducts of the membranous labyrinth?

Answer 49

endolymph fills it and perilymph surrounds it

Question 50

Specialized vestibular sensory receptor inside utricle and saccule of membranous labyrinth?

Answer 50

macula

Question 51

The maculas of the utricle and saccule monitor what type of motion?

Answer 51

static head position and linear motion

Question 52

All three semicircular canals communicate with what structure in the vestibule of the inner ear?

Answer 52

utricle

Question 53

What are the specialized sensory receptor that line the ampulla at the ends of each semicircular canal?

Answer 53

crista ampullaris

Question 54

What motion do the crest ampullaris monitor?

Answer 54

angular/rotational motion

Question 55

What is the duct that extends inward from the vestibule to connect to the sac just deep to the cranial dura?

Answer 55

endolymphatic duct

Question 56

What is the function of the ends-lymphatic duct?

Answer 56

to deliver endolymph just deep to the cranial dura for resorption

Question 57

The trochlear duct of the membranous labyrinth communicates with what structure in the vestibule of the inner ear? Communication occurs via what structure?

Answer 57

communicates with the succule via the ductus reuniens

Question 58

The series of auditory receptors that is continuous along the full length of the cochlear duct?

Answer 58

organ of corti

Question 59

The spiral ganglion located along the turns of the cochlear canal contains cell bodies from which cranial nerve?

Answer 59

CN 8, vestibulocochlear nerve

Question 60

Axonal fibers of cochlear neurons from vestibulocochlear nerve (CN8) are contained in what structure of the membranous labyrinth?

Answer 60

organ of corti

Question 61

What is another name for the vestibular ganglion and where is it located?

Answer 61

Scarpa's ganglion, located within the internal auditory meatus

Question 62

What do the vestibular neurons from vestibulocochlear nerve (CN8) innervate?

Answer 62

Macula of utricle Macula of saccule crista ampullaris

Question 63

Waves of perilymph hydraulic pressure are created by what?

Answer 63

movement of the stapes footplate that is transferred to the perilymph

Question 64

Waves of perilymph hydraulic pressure ascend the cochlear canal in the _____

Answer 64

scala vestibuli

Question 65

Waves of perilymph hydraulic pressure descend the cochlear canal in the _____

Answer 65

scala tympani

Question 66

Waves of perilymph hydraulic pressure dissipate as vibrations in the _____

Answer 66

secondary tympanic membrane in the round window

Question 67

Different parts of the organ of corti are maximally stimulated depending on what?

Answer 67

pitch of the sound

Question 68

The basal end of the organ of Corti is most responsive to what kind of sound?

Answer 68

high pitch

Question 69

The distal end of the organ of Corti is most responsive to what kind of sound?

Answer 69

low pitch

Question 70

If the auditory apparatus is exposed to excessively loud sounds, what is sensitive to damage by that sound?

Answer 70

the organ of Corti

Question 71

What is the origin and insertion of the tensor tympani muscle?

Answer 71

O: bony canal that lies superior and parallel to the Eustachian tube I: manubrium of the malleus

Question 72

What innervates tensor tympani?

Answer 72

medial pterygoid nerve from mandibular nerve V3

Question 73

What is the action of tensor tympani?

Answer 73

pulls the malleus and tympanic membrane medially

Question 74

What is the origin and insertion of the stapedius muscle?

Answer 74

O: wall of tympanic cavity I: neck of stapes

Question 75

What innervates stapedius?

Answer 75

nerve to stapedius which is a branch of facial nerve (CN 7)

Question 76

What is the action of the stapedius?

Answer 76

attenuate movements of the stapes

Question 77

What is the combined function of the inner ear muscles, tensor tympani and stapedius?

Answer 77

contract in response to exposure to loud noises to protect the organ of Croti from damage by decreasing the movements of tympanic membrane and ossicular chain

Question 78

Facial nerve branches within what bony structure to give off ________ nerve which enters the tympanic cavity.

Answer 78

chorda tympani branches from facial nerve within petrous part of temporal bone

Question 79

What are the two types of fibers that are included in chorda tympani?

Answer 79

- taste fibers from anterior 2/3 of tongue (travel from lingual to facial nerve via chorda tympani) - preganglionic parasympathetic fibers traveling to submandibular ganglion

Question 80

The chorda tympani traverses the tympanic cavity along the medial surface of what two structures?

Answer 80

manubrium and tympanic membrane

Question 81

The chorda tympani exits the skull through what opening to enter the intratemporal fossa?

Answer 81

petrotympanic fissure

Question 82

Neuronal fibers from facial nerve that travel in chorda tympani eventually hitch hike on what nerve to reach the tongue and submandibular ganglion?

Answer 82

lingual nerve from mandibular (V3) nerve

Question 83

What are the two major components of the tympanic plexus?

Answer 83

- fibers from internal carotid plexus | - tympanic branch of glossopharyngeal nerve (CN 9)

Question 84

What are the neuronal processes from the internal carotid plexus that contribute to the tympanic plexus?

Answer 84

postganglionic sympathetic neurons from superior cervical ganglion that provide sympathetic innervation to the vessels in the tympanic cavity (vasomotor)

Question 85

What are the two types of neuronal processes from the tympanic branch of the glossopharyngeal nerve that contribute to the tympanic membrane?

Answer 85

- general sensory neurons that innervate the mucosa of Eustachian tubes, tympanic membrane/cavity and mastoid antrum and air cells - preganglionic parasympathetic neurons from glossopharyngeal nerve (CN 9) that pass through the tympanic cavity to form the lesser petrosal nerve to reach the otic ganglion where they synapse and provide secretomotor innervation to the parotid gland