Visual System Flashcards
the blood supply of the photoreceptors of the eye is the _____ , and the supply of the retina and distal CN II is the ______.
choroid (fed by ciliary arteries), central artery of retina…both stem from the opthalmic artery which is a branch of the internal carotid artery.
detached retina occurs between ____ and ______ which take their blood supply from the _____
pigment epithelium, photoreceptive layer, choroid
In rods, the photopigment is ______ and transduction depolarizes rod which _______ ________ __________
rhodopsin, decreases glutamate release
The action of Rhodopsin is to interact with _______ and ______ to convert ______ to _______
transducin, phosphodiesterase, cGMP, 5’GMP
L-cone and M-cone are on ____ (chromosome) but S-cone is on ______ (chromosome)
X-chromosome, autosome
horizontal cells found in the _____ layer have this action (1). Amacrine cells found in ______ layer have this action (2)
outer plexiform layer, (1) sharpen edges of images, inner plexiform layer, (2) increase ganglion sensitivity to moving stimuli
open channels are for ________ and closed channels are for ________. If glutamate binds an open channel, this happens:
off center bipolar and ganglion cells, on center bipolar and ganglion cells cations are allowed through the channel, hyperpolarizing each cell type
neural tube forms the ______ and the neural crest forms the ______
CNS, PNS (cells with nuclei outside brain and spinal cord)
The neural tube is _______ but is found in the ________. It invaginates and makes contact with _______ which induces formation of _________.
ectoderm, mesoderm, surface ectoderm, lens placodes
inner layer of invaginated optic vessicle is _______ and the outer layer is the ________. The layer lying outside of the invagination is the _______.
pigment epithelium, retina, lens placode
lens and cornea are avascular in adult and get nutrients from _________
aqueous humor
neural crest-derived structures include:
sclera, stroma of cornea, ciliary body, iris, choroid
PAX 6 is master gene for eye development and regulates differentiation of _____ and ______. PAX2 regulates differentiation of ______ and ________
optic cup, lens optic stalk, optic nerve
__________ may occur if choroid fissure fails to close in 7th week of development. _________ is the most common phenotype. Mutations in ______ have been linked to optic nerve phenotypes.
Coloboma (cleft), Coloboma iridis (cleft iris), PAX2
cytoskeleton holding each photoreceptor to the basal body is made of:
9 pairs of microtubules
The 3 functions of the pigment epithelium are:
- supplies neural retina with glucose and ions 2. protects photoreceptors from damaging light 3. periodically phagocytoses part of photoreceptor
________ form the optic nerve which exits at the optic disk
ganglion cell axons
cataracts can be caused by these 5 things:
congenital (ex. rubella infection), diabetes, medications, UV, aging
ciliary muscle ______ in response to near objects which _______ the lens.
contracts, fattens
Mydriasis is caused by _________ muscle, miosis is caused by the _______ muscle.
pupillary sphincter, pupillary dilator
glaucoma is caused by:
blockage of canal of Schlemm
cornea layers from outer to inner:
non-keratinized squamous epithelium, Bowman’s membrane (basal lamina), Descemet’s membrane (basement membrane), endothelial cells
The 4 types of retinal ganglion cells are:
parasol (magnocellular), midget (parvocellular), small bistratified, intrinsically photoreceptive (ipRGC)
________ cells receive input primarily from rod cells and have large receptive fields. _______ cells receive input primarily from cone cells and have small receptive fields.
Parasol (M), Midget (P, Beta)
the pretectal nuclei are located adjacent to _________, are involved in the _________ reflex, and receive projections from the ________.
superior colliculi and pineal gland, pupillary light, ipRGC
______ __ ________ controls diurnal rhythms and receives projections from the _______
SCN of hypothalamus, ipRGC
The _______ is involved in reflexive saccades and receives inputs from the ipRGC via the ________.
superior colliculus, brachium of the superior colliculus
The _______ of the _______ controls vision and receives RGC axons via the retinogeniculate projection
LGN of the thalamus
Layers 1-2 of the LGN of the thalamus contain ______ cells and receive input from _______ and contribute to interpreting direction of movement.
M, parasol (M)
All ______ input travels contralaterally to layers 1,4,6 of LGN of thalamus. All _______ input travels ipsilaterally to layers 2,3,5.
nasal, temporal
LGN of thalamus blood supply is _______. pulvinar nucleus of thalamus blood supply is _____.
thalamogeniculate artery of PCA, medial posterior choroidal artery
pupillary light reflex afferent limb synapses at ________. These axons synapse bilaterally at the ________ via the ________. Efferent limb of the reflex are parasympathetic-preganglionic and synapse at ________. These axons then synapse at the ________ muscle and cause it to contract, constricting the pupil.
pretectal nuclei, EW nuclei, ciliary ganglia, pupillary sphincter
The accomodation reflex utilizes the _____, ________, and the ________ before synapsing in the
LGN of thalamus, primary visual cortex, visual association cortex, supraoculomotor area which synapses bilaterally in EW nuclei
pupillary dilation: axons from _______ synapse on T1-T3 and sympathetic preganglionic axons synapse on superior cervical ganglion, then those synapse on pupillary dilator muscle.
hypothalamus
2 causes of horner syndrome due to damage to hypothalamo-spinal neurons:
lateral medullary syndrome, cervical spinal cord transection
2 causes of horner syndrome due to damage to preganglionic sympathetic neurons:
sympathetic chain compression, thoracic spinal cord transection
3 causes of Horner syndrome due to damage to postganglionic sympathetic neurons:
cavernous sinus tumor, carotid artery dissection, jugular foramen syndromes
LGN axons project via _____________ limb of internal capsule which is supplied by the _______ artery.
retrolenticular limb, anterior choroidal
lateral inferior optic radiation (Meyer’s loop) travels through the _______ lobe to the ________ gyrus.
temporal, lingual
medial superior optic radiation travels through the ______ lobe to the _______ gyrus.
parietal, cuneus
optic chiasm blood supply
branches of anterior communicating artery and ACA
optic tract blood supply
anterior choroidal artery of Internal Carotid
blood supply of retrolenticular limb of internal capsule:
anterior choroidal artery
MCA stem is blood supply to
entire optic radiation
MCA inferior trunk is blood supply to:
inferior temporal optic radiation (Meyer’s Loop)
Blood supply to primary visual cortex:
calcarine artery of PCA
Blood supply to superior parietal optic radiation:
PCA
PCA stem supplies all 9 of these locations:
primary visual cortex, superior parietal optic radiation, LGN, VPN, MGN, crus cerebri, occulomotor nerve, red nucleus, substantia nigra
thalamogeniculate artery supplies these 3 locations:
LGN, VPL, VPM
MCA superior trunk supplies these 3 areas:
primary somatosensory cortex, primary somatomotor cortex, frontal eye field
MCA inferior trunk supplies this/these structure(s):
inferior temporal optic radiation (Meyer’s Loop)
__________ supplies blood to the primary somatosensory cortex, primary somatomotor cortex, frontal eye field, and superior temporal optic radiation (Meyer’s Loop)
MCA distal stem
defect in formation of occular dominance columns leads to:
absence of depth perception and steropsis (binocular vision)
This type of cell is found in location IV of primary visual cortex has a concentric center-surround receptive field.
granule cell
This type of cell is found in areas II, III, V, and VI of the primary visual cortex and has a simple receptive field (responds to bars)
simple cell
Dorsal stream visual association includes these 3 areas in the eye, thalamus, and brain respectively:
parasol (M) ganglion cells, LGN layers 1 and 2, Brodman areas 17, 18, and 7a
damage to dorsal stream visual association pathway results in:
patient can identify objects but cannot distinguish which one is closest
visual agnosia happens when damage to visual association cortex Brodman areas:
18, 20, 21
