Ear: Anatomy and Physiology

Question 1

what makes up the external ear?

Answer 1

the pinna, the external auditory canal to the tympanic membrane

Question 2

name the three parts of the ear

Answer 2

> external ear
middle ear
inner ear

Question 3

describe the pinna of the external ear

Answer 3

> helix ridge round the edge of the ear
> antihelix ridge bit inside a bit
> lobule: lobe
> triangular area
> concha
> meatus
> tragus

Question 4

what is the pinna and the auricle made from?

Answer 4

stratified keratinised epithelium and elastic cartilage

Question 5

how long is the external ear canal in adults?

Answer 5

4cm long

Question 6

describe the lateral 1/3rd of the external ear canal

Answer 6

> made of skin and cartilage
ceruminous and sebaceous glands producing wax
thick hairs becoming thinner

Question 7

what are the functions of lateral 1/3 of the external ear canal?

Answer 7

protective barrier and disinfectant

Question 8

what part of the external ear canal has no hairs or cilia and doesn’t produce wax?

Answer 8

the medial 1/3rd

Question 9

describe the shedding of the external ear canal

Answer 9

the skin is being constantly renewed and shed. it grows from the umbo of the tympanic membrane outwards. it is shed in the lateral 1/3rd of canal trapped in wax as part of the cleaning mechanism

Question 10

describe the inner layer of the tympanic membrane

Answer 10

continuous with skin

Question 11

what tissue is the middle layer of the tympanic membrane made form?

Answer 11

fibrous tissue

Question 12

what type of epithelium makes up the inner layer of the tympanic membrane?

Answer 12

ciliated columnar epithelium with goblet cells

Question 13

how large is the tympanic membrane?

Answer 13

1cm in diameter

Question 14

describe the three bones from the tympanic membrane

Answer 14

malleus > incus > stapes

Question 15

what is the function of the ossicles?

Answer 15

they conduct sound waves from tympanic membrane to the inner ear

Question 16

what can cause disruption of sound conduction by the ossicles?

Answer 16

trauma or bony sclerosis (otosclerosis)

Question 17

what lines the middle ear?

Answer 17

continuous respiratory epithelium (that forms the inner layer of tympanic membrane)

Question 18

is the continuous respiratory epithelium lining the middle ear mucous secreting?

Answer 18

yes

Question 19

what does the middle ear connect to via the aditus?

Answer 19

the mastoid system

Question 20

what connects the nasopharynx to the middle ear?

Answer 20

Eustachian tube

Question 21

what does the middle ear contain?

Answer 21

facial nerve

Question 22

what are the important anatomical relations to the middle ear?

Answer 22

> middle cranial fossa
internal carotid artery
sigmoid sinus and internal jugular vein

Question 23

what are the six segments of the facial nerve?

Answer 23

> intracranial
> meatal segment
> labyrinthine segment
> tympanic segment
> mastoid segment
> extratemporal segment

Question 24

what is the taste anterior of the tongue supplied by?

Answer 24

chorda tympani

Question 25

what is cholesteatoma?

Answer 25

skin in the middle ear has become keratinised squamous epithelium which can become destructive. can be congenital or acquired.

Question 26

what is contained in the inner ear?

Answer 26

> bony and membranous labyrinth > cochlear > peripheral vestibular apparatus > vestibulochochlear nerve

Question 27

what does the bony and membranous labyrinth contain?

Answer 27

fluid-perilymph and endolymph

Question 28

what makes up the peripheral vestibular apparatus?

Answer 28

> utricle > saccule > semicircular canal

Question 29

in hearing what window does the foot of stapes vibrate in?

Answer 29

oval window

Question 30

what causes a pressure wave through the fluid in the cochlear?

Answer 30

the foot of stapes vibrating in the oval window

Question 31

what do the hair cells in the organ of corti detect?

Answer 31

the pressure wave through fluid in the cochlear

Question 32

what nerve transmits the detection of the pressure wave by the hair cells in organ of corti to the brainstem?

Answer 32

CNVIII- vestibulocochlear nerve

Question 33

describe the inputs for balance sensation?

Answer 33

> vision > peripheral vestibular system > proprioception

Question 34

what are the outputs for creating balance?

Answer 34

> gaze stabilisation | > postural control

Question 35

what is responsible for detecting head rotation?

Answer 35

semicircular canals

Question 36

describe the effect vestibule-ocular reflex

Answer 36

this inables you to fix you vision on an object even when your head is moving

Question 37

what detects linear acceleration in a vertical plane?

Answer 37

saccule

Question 38

what does the utricle detect?

Answer 38

linear acceleration in horizontal plane

Question 39

what nerve provides sensation to the middle ear?

Answer 39

the tympanic branch of glossopharyngeal nerve CNIX

Question 40

what does the auricular branch of the vagus nerve CNX supply?

Answer 40

sensation to the posterior half of external ear canal

Question 41

what nerve supplies the anterior half of the external ear canal?

Answer 41

the facial nerve

Question 42

what nerve supplies the pinna?

Answer 42

the mandibular branch of the trigeminal nerve CN V3

Question 43

what does otalgia mean?

Answer 43

ear ache