Ear/ Ohre

Question 1

innervation of external ear

Answer 1

CN VII and CN X

Question 2

innervation of skin surrounding external ear

Answer 2

lesser occipital C2
greater auricular C2+3
auriculotemporal CN V3

Question 3

two muscles of ear
innervation
what they control

Answer 3

tensor tympani 
- tensory tympani nerve CN V3
- controls malleus 
stapedius 
- nerve to stapedius CN VII 
- controls stapes

Question 4

muscles associated with function of pharyngotympanic tube

Answer 4

equalises pressure and mucous drainage 
tensor tympani CN V3
tensor veli palatini CN V3
levator veli palatini CN X 
salpingopharyngeus CN X

Question 5

internal auditory meatus

Answer 5

facial nerve CN VII

vestibulocochlear nerve CN VIII

Question 6

parts of tympanic membrane

Answer 6

pars flaccida (loose)
pars tensa (rigid)
equal pressure either side

Question 7

ossicles in epitympanic recess

Answer 7

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

Question 8

layers of cochlea

Answer 8

scala tympani - perilymph (high Na+, low K+)
basilar membrane
scala media - endolymph (low Na+, high K+), have organ of Corti and hair cells
Reissner;s membrane
scale vestibuli - perilymph (high Na+, low K+)

Question 9

vibrations

Answer 9

tympanic membrane -> ossicles -> fenestra vestibuli (oval window) -> basilar membrane

Question 10

auditory pathway

Answer 10

1) cochlea –auditory nerve–> brain stem
2) synapse at cochlea nucleus
3) crosses over to contralateral side
4) synapse at superior olivary complex
5) lateral lemniscus
6) synapse at inferior colliculus (midbrain)
7) medial-geniculate body (thalamus) to auditory cortex (temporal lobe)