Cranial Nerve II Flashcards
Cranial Nerve II
optic nerve
Optic nerve is sensory or motor?
SENSORY ONLY
the eye is composed of which three layers?
Fibrous tunic, Vascular tunic, Retina
Outermost layer of eye
fibrous tunic
middle layer of eye
vascular tunic
innermost layer of eye
retina
fibrous tunic consists of
sclera and cornea
vascular tunic consists of
ciliary body, iris and choroid
bipolar cell bodies are found in which layer of the retina?
inner nuclear layer
bipolar cells relay information to which cells?
ganglion cells
In which layer do bipolar cells synapse with ganglion cells?
inner plexiform layer
depolarized photoreceptors relay information to bipolar cells by synapsing in which layer?
outer plexiform layer
what are the three types of cones?
red, green, blue
what is required for the cones to function properly?
adequate light
where are cones located?
center of retina (fovea)
the periphery of retina is almost completely composed of…
rods
are optic nerve axons myelinated?
yes, oligodendrocytes form the myelin
axons from ganglion cells are conveyed in which layer?
nerve fiber layer
which fibers cross over in the chiasma?
ganglion cell axons originating from the medial/nasal half of retina
what are the three nuclei of termination for optic tract fibers?
lateral geniculate body, superior colliculus, pretectal nucleus of the midbrain
vision pathway
- photoreceptors
- bipolar cells
- ganglion cell
- cell body in lateral geniculate body (thalamus)
- neuron cell body in brodmann area 17
lesion of optic nerve will lead to
loss of depth perception
lesion of optic chiasma will lead to
loss of peripheral vision
lesion of optic tract will lead to
loss of half visual field on OPPOSITE side
which photoreceptor sense only light vs. dark?
rods
which photoreceptor receives color information?
cones
layers of the retina
pigmented layer, photosensitive outer segment, external limiting membrane, outer nuclear layer, outer plexiform layer, inner nuclear layer, inner plexiform layer, ganglion cell layer, nerve fiber layer, internal limiting membrane
which layer contains rod and cone cell bodies?
outer nuclear layer
are retinal ganglion cell axons myelinated?
NO
