Ear

Question 1

what are the two parts of the external ear?

Answer 1

1. auricle (pinna)

2. external acoustic meatus

Question 2

where does the external acoustic meatus end?

Answer 2

tympanic membrane

Question 3

what does the external acoustic meatus start as?

Answer 3

concha

Question 4

what is the function of the concha?

Answer 4

directs sound into external acoustic meatus

Question 5

what are the walls of the external acoustic meatus formed from?

Answer 5

external 1/3 - cartilage

inner 2/3 - temporal bone

Question 6

what connects the tympanic membrane to the surrounding temporal bone?

Answer 6

fibrocartilaginous ring

Question 7

what part of the ossicular chain connects to the tympanic membrane?

Answer 7

malleus

Question 8

what supplies the deep aspect of the external acoustic meatus and tympanic membrane?

Answer 8

maxillary artery

Question 9

what supplies the external ear?

Answer 9

branches of the external carotid artery

Question 10

what innervates the deeper aspect of the auricle and external auditory meatus?

Answer 10

branches of facial and vagus nerves

Question 11

which bone is the middle ear contained in?

Answer 11

temporal

Question 12

where does the middle ear start and end?

Answer 12

start - tympanic membrane

end - lateral wall of inner ear

Question 13

what is the function of the middle ear?

Answer 13

transmit vibrations from the tympanic membrane to the inner ear
(via auditory ossicles)

Question 14

where are the auditory ossicles located?

Answer 14

tympanic cavity in middle ear

Question 15

what are the auditory ossicles?

Answer 15

1. malleus
2. incus
3. stapes

Question 16

what is the function of the auditory ossicles?

Answer 16

transmit sound vibrations through middle ear

Question 17

what does the ossicular chain connect?

Answer 17

tympanic membrane and oval window

Question 18

how is sound transmitted through the middle ear?

Answer 18

1. sound vibrations cause movement in tympanic membrane
2. causes movement in auditory ossicles
3. movement helps to transmit sound waves from tympanic membrane to oval window

Question 19

what are the muscles of the middle ear?

Answer 19

tensor tympani

stapedius

Question 20

what is the function of tensor tympani and stapedius?

Answer 20

acoustic reflex:
contract in response to loud noise
1. inhibits vibrations of ossicles
2. reduces transmission of sound to inner ear

Question 21

what is the origin and insertion of tensor tympani?

Answer 21

origin - auditory tube

insertion - malleus (pulls it medially)

Question 22

what are tensor tympani and stapedius innervated by?

Answer 22

tensor tympani - branch of mandibular nerve

stapedius - facial nerve

Question 23

what does stapedius attach to?

Answer 23

stapes

Question 24

what does the eustachian (auditory) tube connect?

Answer 24

middle ear and nasopharynx

Question 25

what is the function of the eustachian tube?

Answer 25

equalises the pressure of the middle ear to that of the external auditory meatus

Question 26

what are the main functions of the inner ear?

Answer 26

1. convert mechanical signals from middle ear to electrical signals (to transfer information to auditory pathway in brain) 2. maintain balance by detecting position and motion

Question 27

where is the inner ear located?

Answer 27

petrous part of temporal bone | between middle ear and internal acoustic meatus

Question 28

what are the main components of the inner ear?

Answer 28

1. bony labyrinth | 2. membranous labryinth

Question 29

what does the bony labyrinth contain?

Answer 29

- cochlea - vestibule - 3 semi-circular canals contained in perilymph

Question 30

what does the membranous labyrinth contain?

Answer 30

- cochlear duct - semi-circular ducts - utricle - saccule contained in endolymph

Question 31

where is the membranous labyrinth located?

Answer 31

within the bony labyrinth

Question 32

what are the openings from the inner ear to the middle ear and where are they?

Answer 32

oval window - between middle ear and vestibule | round window - between middle ear and scala tympani (part of cochlear duct)

Question 33

what does the vestibule communicate with?

Answer 33

anteriorly - cochlea | posteriorly - semi-circular canals

Question 34

what does the vestibule contain?

Answer 34

saccule | utricle

Question 35

what are the perilymph-filled chambers in the cochlea and where are they?

Answer 35

scala vestibuli - superior to cochlear duct & continuous with vestibule scala tympani - inferior to cochlear duct & terminates at round window

Question 36

what is the ampulla?

Answer 36

swelling at the end of the semi-circular canals

Question 37

what is the organ of hearing?

Answer 37

cochlear duct

Question 38

what are the organs of balance?

Answer 38

vestibular apparatus - semi-circular ducts - saccule - utricle

Question 39

what are the epithelial cells of hearing?

Answer 39

organ of corti

Question 40

what do the saccule and utricle detect?

Answer 40

saccule - movement/acceleration of the head in the vertical plane utricle - movement/acceleration of the head in the horizontal plane

Question 41

is the utricle or saccule bigger?

Answer 41

utricle

Question 42

how is balance information sent to the brain?

Answer 42

1. head moves 2. flow of endolymph in the semi-circular ducts changes speed and/or direction 3. detected by sensory receptors in ampullae 4. send signals to the brain

Question 43

what innervates the inner ear?

Answer 43

vestibulocochlear nerve

Question 44

what are the branches of the vestibulocochlear nerve and what do they supply?

Answer 44

vestibular - utricle, saccule, semi-circular ducts | cochlear - organ of corti

Question 45

what is responsible for auditory reflexes?

Answer 45

inferior colliculi

Question 46

How is information about the movement of the head sent to the CNS?

Answer 46

1. Rotation of head in same plane as one of the semi-circular canals 2. Endolymph moves in opposite direction 3. Cupola and hair cells in ampulla bend in opposite direction 4. Generates impulse to CNS about position head is moving in

Question 47

How is movement detected in the CNS?

Answer 47

1. Impulses generated by semicircular canals 2. Sent via vestibulocochlear nerve to vestibular nuclei (medulla) 3. Vestibular nuclei make connections with nuclei of cranial nerves III, IV and VI 4. Cranial nerves send information to relevant parts of body

Question 48

What is the function of the medial longitudinal fasciculus?

Answer 48

Communication between vestibular nuclei and nuclei of nerves controlling eye movement

Question 49

What is the vestibulo-ocular reflex?

Answer 49

Reflex movements of the eyes in response to stimulation of the vestibular system

Question 50

What is the Oculo-cephalic reflex?

Answer 50

Allows us to maintain gaze fixed on an object when head is moving