Lecture 28: Ear

Question 1

what are the 3 parts of the ear

Answer 1

inner, middle (tympanic cavity), external

Question 2

the inner ear is ____ filled space, within the ____ portion of the ______bone

Answer 2

fluid, petrous, temporal

Question 3

the middle ear is an ____ filled space, within the _____ and ______ portions of the temporal bone

Answer 3

air, petrous and tympanic

Question 4

the external ear emerged from the tympanic part of the _______ bone and is continued by cartilaginous pieces

Answer 4

temporal

Question 5

does hearing require any external structures

Answer 5

nah

Question 6

what is the primary function of the middle ear?

Answer 6

transmit sound vibrations from the lateral external ear to the more medial inner ear

Question 7

the middle ear is composed of what 3 structures

Answer 7

tympanic membrane (eardrum)
ear ossicles (ossicular chain)
oval window (fenestra ovalis)

Question 8

what bone transmits vibrations from outside of the head to the inner ear?

Answer 8

stapes, causes the vibrations in the perilymph of the inner ear

Question 9

all mammals have 2 additional small bones in their middle ear, the _____ and _____

Answer 9

**incus **(b/w other bones of the ossicular chain and articulates w/ them via synovial joints)

**malleus **( body of malleus (manubrium) is fixed to the tympanic membrane so vibrations of membrane are passed along the ossicular chain)

Question 10

what skeletal muscles in the middle ear are associated with the ossicles

Answer 10

**tensor tympani **(inserts on body of malleus)
**stapedius **(inserts on head of stapes)

both at to clarify hearing and protect from loud ass noises

Question 11

what CN innervates the tensor tympani

skeletal muscle of middle ear

Answer 11

CN V3 (mandibular n.)

Question 12

what CN innervates the stapedius

skeletal muscle of middle ear

Answer 12

CN VII (Facial n.)

Question 13

the mucosal lining of the middle ear sends its sesnory input on the _______ nerve

Answer 13

glossopharyngeal n.

Question 14

parasympathetics from the glossopharyngeal n pass through the middle ear cavity via the _____ n

Answer 14

**minor pestrol n. **
carries peganglionic parasympathetics from CN IX to the otic ganglion

Question 15

branch of facial n that carries preganglionic parasympathetic axons from CNVII to the pterygopalatine ganglion

Answer 15

Major pestroal n

Question 16

branch of facial n that carries both preganglionic parasympathetic input to the mandibular and sublingual ganglia and taste from rostral portion of tongue

Answer 16

Chora tympani
crosses tympanic membrane to get to lingual n
its axons hitch hike to oral cavity via lingual n.

Question 17

the ______ tube connects the middle ear to the nasopharynx

Answer 17

Auditory (or eustacean or pharyngotympanic)

Question 18

the auditory tube is typically ______ and must be actively ______ to equalize air pressure

Answer 18

closed, opened

Question 19

what is otitis media

Answer 19

infection of middle ear cavity

can decress sensitivity of hearing by dampening vibrations of the tympanic membrane and possibly lesion any of the nerves passing through the space

Question 20

in _____, the tympanic bulba is large and can be palpated

Answer 20

cats

Question 21

stubborn otitis media can be drained by surgically opening the _______ rostromedially into the nasopharynx

Answer 21

tympanic bulba

Question 22

externally visible part of the ear…

Answer 22

pinna

Question 23

in addition to regular sebaceous glands, the skin of the external auditory canal contains special _______ glands

Answer 23

ceruminous glands (earwax)

Question 24

Branch of superficial temporal artery that supplies some of the rostral concave surface of the ear

Answer 24

Rostral Auricular a.

Question 25

major branch of the external carotid artery that continues on in 4 branches that supply blood to a majority of the ear

Answer 25

caudal auricular a.

Question 26

aura hematoma

Answer 26

pooling of blood b/w the ear and the skin that seperates it from underlying cartilage

Question 27

extensive blood supply to the ears means that even seemingly insignificant trauma can cause….

Answer 27

vascular rupture

Question 28

sensory innervation from the caudal surface of the auricle is carried by ventral and dorsal rami of….

Answer 28

C2