ear

Question 1

temporal bone is composed of what 3 portions

Answer 1

• squamous: contains zygomatic process and mandibular fossa
• Tympanic: middle ear cavity and external acoustic meatus
• Petrous: mastoid and styloid process

Question 2

The inferior portion of the petrous portion of the temporal bone contains what foramen/canal?

Answer 2

• stylomastoid foramen
• carotid canal
• jugular foramen (part)

Question 3

Inner ear is filled with what? What is its function?

Answer 3

• inner ear is fluid filled space within petrous portion of the temporal bone
• hearing and balance

Question 4

What is the middle ear filled with? What is its function?

Answer 4

• middle ear is an air filled space within the petrous and tympanic portions of the temporal bone
• hearing

Question 5

What is the function of the external ear

Answer 5

• external ear emerges from tympanic part of temporal bone
• hearing

Question 6

What is the space between the membranous and bony labyrinths of the inner ear

Answer 6

perilymph space

Question 7

Name the 2 sections of the labyrinth. What is their innervation?

Answer 7

• vestibule
• cochlea
• both innervated by CN VIII

Question 8

vestibule of inner ear

Answer 8

contains all organs of balance and orientation

Question 9

cochlea of inner ear

Answer 9

contains the organ of hearing

Question 10

function of hair cells of inner ear

Answer 10

specialized sensory cells that alter the rate they stimulate an associated sensory nerve in response to bending of hair-like projections

Question 11

differentiate between kinocilium and sterocilia

Answer 11

• kinocilium: tallest single projection out of apex of hair cell
• stereocillia: array of progressively shorter projections lined up next to the kinocilium

* rate of signals from hair cells depends on the direction of the stereocilis bending relative to kinocilium

Question 12

Name the 2 different types of balance organs located in the vestibule of the inner ear

Answer 12

• maculae
• cristae

Question 13

describe the function of maculae of inner ear. Name the 2 maculae

Answer 13

• sheets of hair cells stimulated by linear accelerations
• horizontal macula: located on utricle
• vertical macula: located in the saccule

Question 14

• Describe function of cristae of inner ear
• Where are they located

Answer 14

• crests of hair cells stimulated by fluid flow around the semicircular ducts in response to rotation
• each 1 of the 3 semicircular ducts has a crista located in the ampulla at one end

Question 15

Hair cells in the cochlea are arranged in one long ribon that runs the full length of what?

Answer 15

spiral shaped Cochlear duct

Question 16

What organ in the inner ear is stimulated by sound waves transmitted from the surrounding perilymph into the endolymph of the cochlear duct

Answer 16

organ of corti

Question 17

The location of the sound wave transfer from the perilymph to endolymph depends on what

Answer 17

the frequency of sound

Question 18

The vestibulocochlaer nerve passes into what hole? What 2 main branches does it divide into?

Answer 18

• internal acoustic meatus
• cochlear branch: hearing
• vestibular branch: balance

Question 19

The facial nerve passes into the internal acoustic meatus with the vestibulocochlear n.

• What ganglion does it travel to?
• what branch does it give off from the ganglion?

Answer 19

• facial nerve travels between the cochlea and vestibular organs to reach the geniculate ganglion
• greater petrosal nerve: heads to middle cranial fossa
• facial nerve continues in bone between inner and middle ear spaces

Question 20

geniculate ganglion contains what type of cell bodies

Answer 20

somatic sensory

taste

Question 21

Through what 2 passageways does the inner ear connect to the middle ear cavity

Answer 21

• oval window
• round window

Question 22

Name the three middle ear bones from most external to most internal

Answer 22

• Malleus
• Incus
• Stapes

Question 23

The stapes is connected to what?

Answer 23

oval window

Question 24

bony bulge in middle ear caused by first coil of cochlea is what

Answer 24

promontory

Question 25

What nerve plexus lies in the middle ear? What nerves come to and from plexus

Answer 25

* tympanic plexus * Tympanic nerve from CN IX * lesser petrosal nerve

Question 26

What type of innervation does the tympanic nerve from CN IX carry

Answer 26

presynaptic parasympathetics somatic sensory to middle ear

Question 27

What the function of the stapedius muscle? What nerve is it innervated by

Answer 27

* dampens vibration of the stapes in reaction to potentially damaging loud sounds * facial nerve (CN VII)

Question 28

Where does the chorda tympani emerge from the facial nerve? Where does the facial nerve travel once it gives off chorda tympani

Answer 28

* emerges from posterior wall adjacent to lateral wall of middle ear cavity * facial nerve continues in posterior wall to exit the stylomastoid foramen

Question 29

Chorda tympani passes between what 2 bones in middle ear

Answer 29

crosses tympanic membrane between malleus and incus

Question 30

Origin, insertion, and innervation and action of tensor tympani

Answer 30

* origin: small canal superior to pharyngotympanic tube * insertion: body of malleus inferior to chorda tympani * innervation: branch of mandibular nerve (CN V3) * action: dampen sound: perhaps from own voice

Question 31

What tube arrises from the middle ear and is a passage way between pharynx and tympanic cavity? What is its function

Answer 31

* pharyngotympanic tube * allow pressure equalization * composed of bone and cartilage: cartilage passively closes tube; muscle activity required to open tube

Question 32

What two muscles are responsible for opening up the pharyngotympanic tube?

Answer 32

Levator veli palatine: innervated vagus tensor veli palatine: innervated CN V3

Question 33

Why are young children more likely to get otitis media

Answer 33

in young children, the pharyngotympanic tube has a more horizontal orientation * more likely for infectious materal from respiratory or GI tracts to pass into the middle ear cavity

Question 34

cartilaginous ear canal contains what glands that produce earwax

Answer 34

ceruminous glands

Question 35

NAme the identifiable parts of the tympanic membrane

Answer 35

* flaccid part * tense part * umbo * cone of light: reflected from otoscope

Question 36

If otitis media is causing bulging of the tympanic membrane; what will be distored

Answer 36

the cone of light

Question 37

red and black

Answer 37

red: tragus black: antitragus

Question 38

green and blue

Answer 38

green: helix blue: antihelix

Question 39

The external ear has extensive innervation. Name the nerves responsible

Answer 39

cervical plexus * Lesser occipital * Great auricular Cranial nerves * auriculotemporal nerve (CN V3) * facial nerve * auricular branch of vagus