ocular nerves Flashcards
pneumonic for nerves
LR 6
SO 4
AO 3
what does paralysis of the abducent nerve (VI) cause?
paralysis of lateral rectus causing medial deviation
diplopia in the horizontal plane
what does paralysis of the trochlear nerve (IV) cause?
paralysis of the superior oblique
diplopia when looking down
eye is up and in
what does paralysis of the oculomotor nerve (III) cause?
DOWN AND OUT
fixed pupil dilation
what is the route of the 6th CN?
they come up and over the petrous tip of the temporal bone
aneurysm suspected in …
painful 3rd nerve palsy
fixed dilated pupil
3rd nerve palsy
what is optic neuritis
what is it assoc with
rx?
inflammation of optic nerve
unilateral loss of acuity over hours/days
central scotoma
colour desaturation
assoc with MS
rx: methylprednisolone high dose, then prednisolone
what does light exposure cause photoreceptors to do?
hyperpolarise
do Na+ channels close or open with light exposure?
CLOSE with light
what does the membrane potential become more aligned with when exposed to light?
potassium
what does light convert rhodopsin to
all-trans-retinal
which are for seeing in dim light
cones or rods
rods
which have a low convergence - cones or rods
cones
what is the main receiving area for visual signals from the LGN?
striate cortex
