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Flashcards in Ear Deck (36):
1

What are the names of the ossicles?

Malleus, incus and stapes

2

How can infection spread from nasopharynx to middle cranial fossa?

Nasopharynx to middle ear through Eustachian tube
Middle ear to mastoid air cells through aditus to mastoid antrum
Mastoid air cells to middle cranial fossa

3

What are the muscles that are involved in acoustic reflex?

Tensor tympani and stapedius

4

What is the function of the acoustic reflex?

Inhibit vibrations during loud noise - avoid damage

5

What nerve supplies tensor tympani?

Mandibular nerve

6

What nerve supplies stapedius?

Facial nerve

7

Which part of the temporal bone contains the inner ear?

Petrous part

8

What are the cochlea, vestibule and semicircular canal filled with?

Perilymph

9

What are the electrolyte levels in perilymph?

High potassium, low sodium (same as extracellular fluid)

10

What is the membranous labyrinth?

Epithelial sac within the vestibule, cochlea and semicircular canal

11

What is the membranous labyrinth filled with?

Endolymph

12

What are the electrolyte levels in endolymph?

Low potassium and high sodium (same as intracellular fluid)

13

What are the three types of sensory receptor in membranous labyrinth?

Maculae, christae ampullaris and spiral organ/organ of Corti

14

What is the function of maculae receptor?

Vestibular receptor
Balance, gravity, position - linear acceleration

15

What is the function of christae ampullaris?

Vestibular receptor
Angular acceleration/deceleration

16

Where are the maculae?

Saccule and utricle (parts of membranous labyrinth)

17

Where are christae ampullaris?

Semicircular ducts

18

What type of receptor is spiral organ?

Auditory receptor

19

What is the cochlear duct?

Part of membranous labyrinth in cochlea

20

How many times does the cochlea spiral around the bone axis?

2.5 times

21

What does the cochlear duct split the cochlea into?

Scala vestibule (above) and scala tympani (below)

22

Where are the scala vestibule and scala tympani continuous?

Apex of cochlea - helicotrema

23

Where is the oval window?

Between ossicles and scala vestibule

24

Where is the round window

At end of scala tympani

25

What frequency does the proximal basement membrane respond to?

High frequency

26

What frequency does the distal basement membrane respond to?

Low frequency

27

Where does information from the auditory pathway get projected to in cerebral cortex?

Heschl's gyrus - temporal lobe

28

Where is the cell body of the primary neuron in the auditory pathway?

Spiral ganglion

29

Where does information in the auditory pathway cross the midline?

Trapezoid body (near pons)

30

Where does the information in the auditory pathway first get passed to in the brainstem?

Cochlear nuclei

31

Where is the information passed to after it has crossed the midline?

Superior olivary nuclei

32

After the superior olivary nuclei, where does the information in the auditory pathway go?

Inferior colliculi

33

Where does the information from the auditory pathway go in the thalamus?

Medial geniculate nuclei

34

Why is the auditory pathway bilateral?

To help localise sound - compare timing and volume

35

What is conduction deafness?

Problems conducting soundwaves in outer or middle ear

36

What is sensorineural deafness?

Damaged hair cells in cochlear or damaged vestibulocochlear nerve