Visual System Part II And III Flashcards
What are the first order neurons of the optic pathway
Ganglion cells that travel in the optic nerve into the optic chiasm
What do axons coming from the lateral retina do at the optic chiasm
Do not decussate, they enter the ipsilateral optic tract
What do the axons that come from the medial retina do at the level of the chiasm
Decussate and enters the contralteral optic tract
Where do fibers from each optic tract terminate
In the lateral geniculate nucleus
What are the second order neurons in the optic pathways
Geniculate fibers
Where do the geniculate fibers travel
Through the internal capsule and corona radiata to the primary visual cortex in the banks of the calcarine sulcus
What is the extra geniculate pathways
Sensory fibers for pupil/EOM movements
Where do the extra geniculate fibers enter
They bypass the LGN and enter the pretectal area and the superior colliculus
What is the pretectal area important for
Pupillary light reflex
What is the superior colliculus and the pretectal area involved with
Directing eyes toward visual stimuli
Is the extra geniculate pathway involved with vision
No
Fibers arising from the lateral geniculate nucleus curve around the lateral wall of the lateral ventricular as the _________
Optic radiation
Where do the optic radiations terminate
In the cortex adjacent to the calcarine sulcus
What part of the visual field does the upper retina represent
Lower
Where does the upper retina projector in the calcarine sulcus
Above the calcarine sulcus
What part of the VF does the lower retina represent
Upper VF
What part of the calcarine sulcus does the lower retina project to
Below the calcarine sulcus
How do projections from the upper retina course in the optic radiations
Upwards in parietal lobe, around lateral ventricle to visual cortex above calcarine
How do the lower retina optic radiations course back
Downwards through temporal lobe towards calcarine sulcus
Where do the macular fibers project
In a broad region, some go with the superior optic radiations, some with the inferior optic radiations
Lesions affecting the optic radiation and the macula
Often cause visual loss in one quadrant of the vision field with macular sparing
Superior retina projects
To the cortex above the calcarine sulcus
Inferior retina projects to the
Cortex below the calcarine sulcus
Where is the macula represented
More posteriorly and peripheral fields than anteriorly. Represents a large area of the primary visual cortex
Representation of the macula compared to its size
Disproportionately large
What is the blood supply of the optic radiations
MCA
What is the blood supply for the superior branch of the optic radiation
Superior branch of MCA
What is the blood supply of the inferior optic radiations
Inferior branch of the MCA
What is the blood supply to the visual cortex
PCA
How are visual named
According to the VF loss and NOT ACCORDING TO THE AREA OF THE RETINA OR THE OPTIC PATHWAY THAT IS NONFUNCTIONAL
Loss of the whole VF in one or both eyes
Blindness
Loss of half of a VF
Hemianopia
Loss of one quarter of a VF
Quadrantanopia
Same field loss in both eyes
Homonymous
Opposite field loss in both eyes
Heteronimous