Flashcards in Visual System Deck (19):
The lateral geniculate nucleus projects to which lobe?
The ophthalmic artery is a branch of which vessel?
Sudden onset of complete monocular blindness is the consequence of what sort of lesion?
Optic nerve (on affected side)
Inferior optic radiations are responsible for what part of the visual field?
What are the 3 key feature sod the accommodation reflex?
1. Lens thickening
3. Pupil constriction
In which part of the retina are cone cells particularly dense?
The fovea of the macula
What are the 3 layers of the retina?
2. Pigmented layer
3. Neural layer
Within which layer of the retina are photoreceptor cells found?
What is special about the optic disc (in terms of content) ?
No photoreceptor cells at all!
What is the "blind spot"?
It refers to the optic disc. Indeed, there are no photoreceptor cells at the optic disc, it is the point where optic nerve leaves.
What are rod cells responsible for?
Black and white vision, low levels lighting vision
What are cone cells responsible for?
colour and high definition (= central vision)
What are the lateral geniculate nuclei?
They are relay point between optic tracts and visual cortex
What is macular sparing?
Central vision is preserved
What sort of pathology is macular sparing a feature of?
Vascular damage to the occipital lobe.
Occipital lobe has dual blood supply, posterior cerebral artery for most but middle cerebral for occipital pole.
Occipital pole is responsible for macular vision, and therefore if PCA is affected can lose all vision except macula supplied by MCA.
Which nerve is responsible for the afferent limb of the accommodation reflex?
CN II optic
Which nerve is responsible for the efferent limb of the accommodation reflex?
CN III occulomotor
Which nerve is responsible for the afferent limb of the corneal reflex?
Ophtalmic branch of trigeminal nerve CN V