Ear

Question 1

What are the names of the ossicles?

Answer 1

Malleus, incus and stapes

Question 2

How can infection spread from nasopharynx to middle cranial fossa?

Answer 2

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

Question 3

What are the muscles that are involved in acoustic reflex?

Answer 3

Tensor tympani and stapedius

Question 4

What is the function of the acoustic reflex?

Answer 4

Inhibit vibrations during loud noise - avoid damage

Question 5

What nerve supplies tensor tympani?

Answer 5

Mandibular nerve

Question 6

What nerve supplies stapedius?

Answer 6

Facial nerve

Question 7

Which part of the temporal bone contains the inner ear?

Answer 7

Petrous part

Question 8

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

Answer 8

Perilymph

Question 9

What are the electrolyte levels in perilymph?

Answer 9

High potassium, low sodium (same as extracellular fluid)

Question 10

What is the membranous labyrinth?

Answer 10

Epithelial sac within the vestibule, cochlea and semicircular canal

Question 11

What is the membranous labyrinth filled with?

Answer 11

Endolymph

Question 12

What are the electrolyte levels in endolymph?

Answer 12

Low potassium and high sodium (same as intracellular fluid)

Question 13

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

Answer 13

Maculae, christae ampullaris and spiral organ/organ of Corti

Question 14

What is the function of maculae receptor?

Answer 14

Vestibular receptor

Balance, gravity, position - linear acceleration

Question 15

What is the function of christae ampullaris?

Answer 15

Vestibular receptor

Angular acceleration/deceleration

Question 16

Where are the maculae?

Answer 16

Saccule and utricle (parts of membranous labyrinth)

Question 17

Where are christae ampullaris?

Answer 17

Semicircular ducts

Question 18

What type of receptor is spiral organ?

Answer 18

Auditory receptor

Question 19

What is the cochlear duct?

Answer 19

Part of membranous labyrinth in cochlea

Question 20

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

Answer 20

2.5 times

Question 21

What does the cochlear duct split the cochlea into?

Answer 21

Scala vestibule (above) and scala tympani (below)

Question 22

Where are the scala vestibule and scala tympani continuous?

Answer 22

Apex of cochlea - helicotrema

Question 23

Where is the oval window?

Answer 23

Between ossicles and scala vestibule

Question 24

Where is the round window

Answer 24

At end of scala tympani

Question 25

What frequency does the proximal basement membrane respond to?

Answer 25

High frequency

Question 26

What frequency does the distal basement membrane respond to?

Answer 26

Low frequency

Question 27

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

Answer 27

Heschl’s gyrus - temporal lobe

Question 28

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

Answer 28

Spiral ganglion

Question 29

Where does information in the auditory pathway cross the midline?

Answer 29

Trapezoid body (near pons)

Question 30

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

Answer 30

Cochlear nuclei

Question 31

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

Answer 31

Superior olivary nuclei

Question 32

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

Answer 32

Inferior colliculi

Question 33

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

Answer 33

Medial geniculate nuclei

Question 34

Why is the auditory pathway bilateral?

Answer 34

To help localise sound - compare timing and volume

Question 35

What is conduction deafness?

Answer 35

Problems conducting soundwaves in outer or middle ear

Question 36

What is sensorineural deafness?

Answer 36

Damaged hair cells in cochlear or damaged vestibulocochlear nerve