the ear

Question 1

what is the ear composed of?

Answer 1

the outer, middle and inner ear

Question 2

what is the outer ear compromised of?

Answer 2

• the pinna
• auricular muscles
• ear canal
• ear drum

Question 3

what is the role of the auricular muscles?

Answer 3

move the pinna to locate sounds and communicate

Question 4

what nerve is related to the auricular muscles?

Answer 4

facial nerve (cranial nerve VII)

Question 5

where is the middle ear separated from the outer ear?

Answer 5

at the tympanic membrane

Question 6

what is the middle ear composed of?

Answer 6

ossciles

Question 7

how does the tympanic membrane respond to sound waves?

Answer 7

it vibrates

Question 8

what is the function of the tympanic membrane vibration?

Answer 8

to transmit sound vibrations to the middle ear ossicles

Question 9

what are the ossicles?

Answer 9

a chain of three small bones

Question 10

what are the names of the ossicles?

Answer 10

hammer (malleus), anvil (incus) and stirrup (stapes)

Question 11

what is the function of the ossciles?

Answer 11

to transmit and amplify vibrations

Question 12

where do the ossicles transmit vibrations to?

Answer 12

the oval window of the inner ear

Question 13

where is the middle ear housed?

Answer 13

inside the temporal bone of the skull

Question 14

what is the tympanic bulla?

Answer 14

a bulbous ventral expansion of the temporal bone housing the middle ear

Question 15

what type of lining does the middle ear have?

Answer 15

a mucous membrane

Question 16

how does the middle ear communicate with the pharynx?

Answer 16

via the auditory (eustachian) tube

Question 17

what are the functions of the auditory tube?

Answer 17

pressure equalisation and drainage of glandular secretions

Question 18

which autonomic nerves run close to the middle ear?

Answer 18

sympathetic nerves to the head

Question 19

what is the role of sympathetic nerves in the head?

Answer 19

“fight or flight” response

Question 20

list key sympathetic effects in the head

Answer 20

• pupil dilation
• eyelid retraction
• skin vasoconstriction

Question 21

which cranial nerve also runs close to the middle ear?

Answer 21

the facial nerve (CN VII)

Question 22

what is the function of the facial nerve?

Answer 22

muscles of facial expression and auricular muscles

Question 23

what is horner’s syndrome?

Answer 23

interruption of sympathetic nerve innervation to the head

Question 24

what pupil change occurs in horner’s syndrome?

Answer 24

miosis (pupil constriction)

Question 25

what eyelid change occurs in horners syndrome?

Answer 25

ptosis (drooping eyelid)

Question 26

what happens to the third eyelid in horner's syndrome?

Answer 26

protrusion

Question 27

is horner's syndrome usually unilateral or bilateral?

Answer 27

unilateral

Question 28

what is the equine guttural pouch?

Answer 28

an outpouching of the auditory tube connecting the middle ear to the pharynx

Question 29

what is a proposed function of the guttural pouch?

Answer 29

brain cooling

Question 30

how is the guttural pouch divided?

Answer 30

into medial and lateral compartments by the stylohyoid bone

Question 31

name important structures near the guttural pouch

Answer 31

- major blood vessels - cranial nerves IX, X, XI, XII

Question 32

what causes guttural pouch mycosis?

Answer 32

fungal infection, most commonly aspergillus

Question 33

why can guttural pouch mycosis be difficult to detect early?

Answer 33

fungal plaques may be hidden until erosion occurs

Question 34

list possible complications of guttural pouch mycosis

Answer 34

- nerve dysfunction - dysphagia - fatal haemorrhage

Question 35

what is the approximate fatal haemorrhage risk?

Answer 35

almost 50% of cases

Question 36

how is guttural pouch mycosis treated?

Answer 36

prolonged topical and systemic antifungal therapy

Question 37

what fluids fill the membranous and bony labyrinths?

Answer 37

endolymph (membranous) and perilymph (bony)

Question 38

which structure is responsible for hearing?

Answer 38

the cochlea (cochlear duct)

Question 39

what are the two main functions of the inner ear?

Answer 39

hearing and balance

Question 40

which structures are responsible for balance?

Answer 40

semicircular canals, saccule and utricle

Question 41

which cranial nerve carries vestibular information to the brain?

Answer 41

vestibulocochlear nerve (CN VIII)