Ear

Question 1

What is the external ear composed of?

Answer 1

Elastic cartilage covered with integument

Question 2

What is the lobule composed of?

Answer 2

NO cartilage, just loose connective tissue

Question 3

What is the blood supply to the external ear?

Answer 3

Posterior auricular artery and superficial temporal artery both off of the external carotid

Question 4

What is the sensory innervation for the external ear?

Answer 4

Auriculotemporal (v3) and greater auricular (c2,c3)

Question 5

What type of glands does the external acoustic meatus contain?

Answer 5

Ceruminous glands - make wax

Question 6

What does the external acoustic meatus lead to?

Answer 6

A canal that leads to the tympanic membrane

Question 7

What is the function of the tympanic membrane?

Answer 7

Moves with sound and transmits to ossicles

Question 8

What type of epithelium is the external surface of the tympanic membrane comprised of?

Answer 8

Stratified squamous epithelium

Question 9

What type of epithelium is the internal surface of the tympanic membrane comprised of?

Answer 9

Simple cubiodal epithelium

Question 10

What innervates the tympanic membrane?

Answer 10

Auriculotemporal (external) and branches of vagus (internal)

Question 11

What can cause a perforated tympanic membrane?

Answer 11

Increase in middle ear pressure from fluid or barotrauma; or from external trauma

Question 12

What should you not give patients with a perforated tympanic membrane?

Answer 12

Gentamicin

Question 13

What separates the external ear and the middle ear?

Answer 13

Tympanic membrane

Question 14

What are the 2 parts of the middle ear?

Answer 14

Epitympanic recess and tympanic cavity

Question 15

Medial border of middle ear

Answer 15

Labyrinth wall

Question 16

Anterior border of middle ear

Answer 16

carotid wall and opening of pharyngotympanic tube

Question 17

Posterior border of middle ear

Answer 17

Mastoid wall

Question 18

Floor of middle ear

Answer 18

Jugular wall

Question 19

Roof of middle ear

Answer 19

Tegmental wall

Question 20

What nerves can be seen running in the middle ear?

Answer 20

Chorda tympani and lesser petrosal nerve

Question 21

What passes between malleus and incus?

Answer 21

Chorda tympani

Question 22

What are the ossicles of the middle ear and what is their purpose?

Answer 22

Malleus, incus, stapes - amplify and transmit vibrations from tympanic membrane to oval window

Question 23

What connects the tympanic cavity to the nasopharynx?

Answer 23

Pharyngotympanic tube (Eustachain tube)

Question 24

Purpose of pharyngotympanic tube?

Answer 24

Equalize pressure

Question 25

What is the pharyngotympanic tube made of?

Answer 25

Bone and mostly elastic cartilage

Question 26

What muscles open the pharyngotympanic tube?

Answer 26

Tensor veli palatini, levator veli palatini, salpingopharyngeus

Question 27

What are the muscles in the middle ear?

Answer 27

Tensor tympani and stapedius

Question 28

What is the action and innervation of tensor tympani?

Answer 28

Action = reduce amplitude of sound by tensing tympanic membrane IN: CN V

Question 29

What is the action and innervation of stapedius?

Answer 29

Action = Prevent excessive movement of stapes and reduce oscillatory range IN: CN VII

Question 30

Otitis media

Answer 30

Middle ear infection, accumulation of fluid/pus that causes ear pain Tympanic membrane appears red and swollen

Question 31

What happens if otitis media goes untreated?

Answer 31

Impaired hearing and scarred ossicles and possibly mastoiditis

Question 32

Mastoiditis

Answer 32

Infection of mastoid process cells that can spread into cranial fossa via petrosquamous cranial suture

Question 33

What 2 labyrinths does the inner ear consist of?

Answer 33

Bony and membranous

Question 34

Where is the membranous labyrinth?

Answer 34

Inside the bony labyrinth

Question 35

What fluid does the bony labyrinth contain and where does it drain?

Answer 35

Perilymph and it drains via perilymphatic duct (cochlear aqueduct) and into subarachnoid space

Question 36

What fluid does the membranous labyrinth contain and where does it drain?

Answer 36

Endolymph and it drains via endolymphatic duct and into dural venous sinuses

Question 37

Composition of perilymph?

Answer 37

Similar to CSF - high na, H, ca; and low K

Question 38

Composition of endolymph?

Answer 38

High K and low na

Question 39

Source of endolymph?

Answer 39

Stria vascularis

Question 40

Describe the setup of hair cells

Answer 40

Multiple stereocilia that increase in height along a certain direction with one kinocilia that is the tallest

Question 41

If the stereocilia are moved toward kinocilia what happens?

Answer 41

mechanoelectric K+ channels will open

Question 42

If the stereocilia are moved away from kinocilia what happens?

Answer 42

Mechanoelectric K+ channels will close

Question 43

What type of nerves supply hair cells?

Answer 43

Afferent and Efferent (modulate sensitivity)

Question 44

Where will you find hair cells?

Answer 44

Cochlear duct, macula, ampulla

Question 45

What do the hair cells interact with in the organ of corti to move back and forth?

Answer 45

Tectorial membrane

Question 46

What makes up the cochlea?

Answer 46

Scala vestibuli, scala media, and scala tympani

Question 47

What are scala vestibuli and scala tympani made of?

Answer 47

Perilymph

Question 48

What does the stapes vibrate on?

Answer 48

Oval window

Question 49

What does the stapes vibrations cause?

Answer 49

Fluid vibrations within the scala vestibuli and onward

Question 50

Cochlear duct

Answer 50

Scala media

Question 51

What vibrates with sound and helps to move the hair cells?

Answer 51

Basilar membrane

Question 52

Basilar membrane and hair cells in the scala media (cochlear duct) that senses sound

Answer 52

Organ of corti

Question 53

Where do high pitch/frequencies go on the basilar membrane?

Answer 53

Base - not very far down it

Question 54

Where do low pitch/frequencies go on the basilar membrane?

Answer 54

Apex - travel far down it

Question 55

Where are the utricle and saccule?

Answer 55

In the vestibule (bony labyrinth)

Question 56

What is housed within the utricle and saccule?

Answer 56

Each has a macula

Question 57

What does the macula do?

Answer 57

Senses gravity and linear acceleration

Question 58

Describe the setup of a macula

Answer 58

A gelatinous membrane = otolithic membrane that has calcium carbonate crystals on it = otoconia that both sit on top of hair cells

Question 59

What is within the semi-circular canals?

Answer 59

Semi-circular ducts

Question 60

What is within the semi-circular ducts?

Answer 60

Ampullas

Question 61

What do ampullas do?

Answer 61

Sense rotation and dynamic equilibrium

Question 62

What is the structure within the ampulla that gets pushed by endolymph when rotation occurs?

Answer 62

Cupulla

Question 63

Where does the cupulla sit?

Answer 63

On top of hair cells

Question 64

What makes up the inner ear?

Answer 64

Cochlea, vestibule, semi-circular canals

Question 65

Hearing loss that effects the external and middle ear

Answer 65

Conductive hearing loss

Question 66

Hearing loss that effects the inner ear, is noise and age related

Answer 66

Sensorineural hearing loss

Question 67

Hearing loss due to problems in the CNS

Answer 67

Central hearing loss

Question 68

Meniere's syndrome

Answer 68

Increased endolymph volume that causes dizziness, vertigo, high-pitched rushing sound and some hearing loss

Question 69

Viral labyrinthitis

Answer 69

Same symptoms as meniere's syndrome but is only present for about one week and then goes away