L16 - Ear, Orbit, and Nasal Cavities

Question 1

outer ear: auricle

Answer 1

layer of skin over cartilage framework

lobule = fibrous fatty tissue with no cartilage

Question 2

outer ear: sensory innervation

Answer 2

• great auricular nerve
• auriculotemporal nerve
• lesser occipital

Question 3

outer ear: external acoustic (auditory) meatus

Answer 3

• from auricle to tympanic membrane
• 2.5 cm in length
• S-shaped
• lined by skin and ceruminous glands

Question 4

describe the tympanic membrane

Answer 4

• dense fibrous membrane
• covered by skin externally
• covered by mucosa internally

Question 5

describe the tympanic cavity

Answer 5

• air-filled cavity within petrous portion of temporal bone
• round window
• oval window

Question 6

describe the round window

Answer 6

• enclosed by secondary tympanic membrane: undergoes compensatory excursions with movement of stapes

Question 7

describe the oval window

Answer 7

• closed by footplate of stapes

Question 8

what are the 3 auditory ossicles

Answer 8

malleus, incus, stapes (attached to oval window)

Question 9

describe the stapedius muscle

Answer 9

• inserts onto neck of stapes
• contracts reflexively in response to loud sounds
• ***exam: innvervated by CN 7

Question 10

describe the tensor tympani muscle

Answer 10

• inserts onto malleus
• contracts reflexively to loud sounds
• innervated by CN V-3

Question 11

EXAM: what is the CN IX?

Answer 11

tympanic nerve

• GSA to mucosa of tympanic cavity, mastoid air cells, and auditory tube

Question 12

describe the lateral petrosal nerve

Answer 12

• leaves tympanic cavity to floor of middle cranial fossa
• descends through foramen ovale to infratemporal fossa
• ends in otic ganglion

Question 13

where does the inner ear lie?

Answer 13

within petrous part of temporal bone

Question 14

what does the inner ear consist of?

Answer 14

• bony labyrinth (lined w periosteum)
• membranous labyrinth
  supplied bylabyrinthine artery

Question 15

what is the basilar artery formed by?

Answer 15

the fusion of two vertebral arteries

Question 16

describe the cochlea

Answer 16

• resembles a snail shell
• three turns
• round window (fenestra cochlea)

Question 17

describe what the vestibule contain?

Answer 17

• utricle

- saccule

Question 18

**what passes through the cribiform plate?

Answer 18

olfactory nerve

Question 19

in regards to the extrinsic muscles of the eye, where does the parasympathetic tie into?

Answer 19

• from edinger-westphal nucleus

Question 20

describe the opthalmic nerve (V1)

Answer 20

• lacrimal nerve

- nasociliary nerve

Question 21

in regards to the mucous membranes, vestibules receives what from where?

Answer 21

parotid duct: opposite upper second molar