Visual Fields and System Flashcards
what is pigment of a photoreceptor?
rhodopsin
where are rods located in retina?
only in peripheral
where are cones located in retina?
center of retina mainly
increased ICP leads to what in optic disc?
papilledema
where does left visual field map in cortex?
right hemi
where does right visual field map in cortex?
left hemi
where does vision synapse in thalamus?
LGN
where is primary visual cortex in occipital lobe?
primarily in the medial aspect of it
the lower portion of the primary visual cortex is for the upper or lower visual field?
upper visual field
the upper portion of the primary visual cortex is for the upper or lower visual field?
lower visual field
what divides the upper and lower portions of the primary visual cortex?
calcarine sulcus
the left eye left visual field hits where on retina?
medial portion of left retina
the left eye right field hits where on retina?
temporal aspect
the right eye right visual field hits where on retina?
medial portion of right retina
the right eye left visual field hits where on retina?
temporal aspect
what two visual fields cross in the optic chiasm?
right eye right visual field and left eye left visual field
clip of right optic nerve leads to what change in vision? what is this called?
loss of right eye vision, right anopia
clip of left optic nerve leads to what change in vision? what is this called?
loss of left eye vision, left anopia
clip of optic chiasm leads to what change in vision? what is this called?
bilateral hemianopia…loss of outer fields in both eyes
what is a common lesion that causes bilateral hemianopia? where is issue with bilateral hemianopia?
pituitary lesion…in optic chiasm
clip of right optic tract leads to what change in vision? what is this called?
loss of left visual field in left eye and left visual field in right eye
called left homonymous hemianopia
what is homonymous hemianopia?
cut in optic tract, lose opposite field of side of lesion on both eyes
what usually causes homonymous hemianopia?
cut in optic tract
after the LGN, what are the two tracts to the primary visual cortex?
Meyer loop and dorsal optic radiation
where does meyer loop go through on way to visual cortex?
temporal lobe
where does dorsal optic radiation go through on way to visual cortex?
parietal lobe
meyers loop carries information about what portions of the visual field? and hits the visual cortex in what portion?
upper visual fields, but in cortex is on the lower portion
a lesion in the right meyers loop leads to what visual changes?
loss of left upper field quadrant in both eyes
what is a lesion in meyers loop called?
upper quadrantinopia
what are two causes of meyers loop lesions?
right temporal lesion and MCA ischemia
if lesion occurs in the left dorsal optic radiation, where is visual field loss? what is this called?
right lower quadrantinopia…right lower visual fields of both eyes
what are two lesions that can lead to lower quadrantinopia?
parietal lobe lesion and MCA ischemia
what are changes seen in left sided occipital lobe lesion? what is this called?
right visual field loss with macular sparing in both eyes…called right hemianopia with macular sparing
what are two lesions that lead to hemianopias with macular sparing?
occipital lobe lesions and PCA ischemia
what is central scotoma? what is another name for this?
macular degeneration…loss of only central vision
in pupillary reflex, where does signal from CNII go when we have light shined in eye?
to pretectal nuclei
where does the pretectal nuclei activate after it receives input from CNII that light is bright in an eye?
bilateral edinger westphal nuclei
what does edinger westphal nucleus do after stimulation from pretectal nuclei in the pupillary reflex?
leads to parasympathetic output bilaterally to constrict pupils
the parasympathetic output to constrict the eye starts with what nuclei?
edinger westphal nuclei
where does edinger westphal nuclei synapse in parasympathetic tract to eye?
ciliary ganglia
ciliary nerves in the parasympathetic tract go to what muscle in the eye and cause what?
sphincter pupillae muscle and lead to constriction of the pupil
what is pupillary constriction called?
miosis
what is pupillary dilation called?
mydriasis
what is the first nuclei in sympathetic process to dilate the eye?
hypothalamus to thoracic lateral horn
what is second nuclei in sympathetic process to dilate the eye?
thoracic lateral horn to superior cervical ganglion
what is third nuclei in sympathetic process to dilate the eye?
from superior cervical ganglion along the internal carotid to the pupillary dilator muscles
