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92 Cards in this Set
- Front
- Back
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What is the visual pathway?
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Retina-> optic nerve->optic chiasm->optic tract-->lateral geniculat nuclei of thalmus-> geniculocalcarian tract->visual cortex area 17
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3 retinal cell types and what makes the optic nerve?
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Rods and cones
bipolar cells ganglion cell** make optic nerve |
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The rods and cones are what?
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The receptors
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The flow of info from the eye goes rods and cones-->???
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bipolar cells->ganglion cells--> optic nerve
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The center of the macula lutea is what?
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Fovea
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The optic papilla or nerve head is the?
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Blind spot
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The quadrants of the retina are?
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Upper nasal
Lower nasal Upper temporal Lower temporal |
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The blind spot correlates to what?
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Location of optic nerve head on NASAL side of retina
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The blindspot is on the nasal or temporal side?
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Nasal
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The entire area which can be "seen by the patient without movement of the head and with the eyes fixed on a single spot?
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Visual field
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The visual field quadrants are defined by?
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The same quadrants of as the retina
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How do you test monocular visual fields?
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you test each eye seperately and place the Fovea at the center
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The horizontal and vertical meridians in monocular visual use what to name their quadrants?
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UNQ, LNQ, UTQ, LTQ
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The blind spot is located where?
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15* to the temporal side of the visual fields of eac eye on the horizontal meridian
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What corresponds to the location of the optic nerve head 15* to the nasal side of the retina of the retina in each eye?
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The blind spot.
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The binocular visual fields includes what?
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The monocular fields of each eye
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In binocular field the combination of monocular visual fields has the what allign with eachother?
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Foveas
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The left visual field is seen by what?
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Both the left and right eyes
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What is the right visual field?
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Seen by both right and left eyes
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The monocular cresent for each eye is only seen by what?
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The nasal retina of the same eye.
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binocular vision is dependent on what?
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The extraocular muscles aligning the eyes so that the image falls on the corresponding points on the retina of each eye.
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What is essential for the brain to perceive 1 image?
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Extraocular muscles aligning the eyes so the image falls on corresponding pts.
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What occurs when the images are not aligned to fall on corresponding points of the retina
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Diplopia
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THe image of an object in the visual field is ___ and _____ on the retina
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Inverted and reversed left to right
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The temporal field of the left eye is seen by???
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Nasal retina of the left eye
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Nasal field of the left eye is seen by?
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Temporal retina of left eye
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Superior field of the left eye is seen by?
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Inferior retina of left eye
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Inferior field of te left eye is seen by?
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Superior retina of left eye
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Optic nerve is?? And extends from what to what?
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SSA and extends from retina to optic chiasm
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The optic nerve develops as an outgroth of what? It is essentially a CNS tract and has no nuclei associated with it in the???
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Diencephalon and in the brainstem
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What is the optic nerve composed of?
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Axons of ganglion cells in ipsilateral retina
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Optic chiasm is located just anterior to the pituaitary in the anterior portion of this??
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Sella turcica
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What occurs in the chiasm?
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Partial crossing of the axons from each optic nerve
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AXONS FROM WHAT FIELDS CROSS AND DON"T CROSS
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Temporal fields CROSS
Nasal fields DO NOT CROSS |
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Partial crossing is essential for what?
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Binocular vision
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Optic tract is a continuation of the optic nerve axons from the optic chiasm to what?
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Lateral geniculate nucleus of the thalamus
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Optic tract fibers terminate in 2 places the LGN and ??
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The superior coliculus
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Each tract contains axons that recieve input form what?????
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Contralateral visual fields
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The L. optic tract reieves input from?
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The right visual field
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From the optic tract to the visual cortex each side of the brain deals with what?
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The contralateral visual field
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What nuceis of the hypothalmus also receive visual input from the optic chiasm level?
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Suprachiasmatic
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The LGN is the _____ termination of optic tract axons and recieves input from____ visual field.
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Primary termination of optic tract axons and recieves input from contralateral visual field
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Axons of LGN neurons travel to which area?? Via these 2 pathwyas in the internal capsule that are part of the geniculocarlcarine tract
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Area 17 via the geniculocalcarine tract that is in the retrolenticular and sublentricular portions of the internal capsule
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These take a looping course into the temporal lobe on the way to the visual cortex?
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Meyer's loop from upper visual fields
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Macular fibers are located where in the optic radiation?
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Intermediate
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Optic radiation=
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geniculocalcarine tract
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The primary visual cortex is located where?
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In area 17 on either side of and within the calcarine fissure.
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Where do upper visual fields project to?
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Lingual gyrus
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Lower visual fields project to the?
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Cuneate gyrus
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Where is the macular representation in AREA 17?
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Most caudal part
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The peripheral field representation is in what of area 17?
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Rostral 2/3rds of Area 17
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Lesions in area 17 result in?
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Blindness in the contrallateral visual field
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What is the association visual cortex?
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Areas 18 and 19
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Where does the input of assosiation visual cortex come from?
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From area 17 and othersq
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What deals with the complex aspects of vision such as recognintion of subjects and their significants?
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Area 18 and 19, the assocsiation visual cortex
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Lesions of the association visual cortex cause what?
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Visual agnosia
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Areas 18 and 19 have 2 other duties what are they?
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Automatic scanning movements
Accomodation/convergance reflex |
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Failure of coordination of extraocular eye muscles, resulting in deviation of the affected eye and dipolpia?
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Strabismus (squint)
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Double vision due to failure of the image to be aligned on corresponding pts of the retinae of the left and right eyes?
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Diplopia
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Lazy eye: decreased visual acuity in the absence of anatomical defects in visual pathway
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Amblyopia
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Island of visual loss within visual field
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Scotoma
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Defective vision or blindness in approximately 1/4 of the visual field
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Quadrantanopsia or quadrantanopia
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Defective vision in 1/2 of visual field
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hemianopsia
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Visual defects restricted to either the right or the left visual field
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homonymous defects
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visual defects involving parts of both the left and right visual fields so that visual field defects are non overlaping. ALMOST ALWAYS occurs at chiasm
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Heteronymous defects
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Visual defects are equivalent in each monocular visual field?
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Congruous defects
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Visual defects are not equivalent in each monocular visual field
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incongruous defects
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Visual defects are in the upper and lower aspect of visual fileds
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Altitudinal defects
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Damage to anterior optic chiasm affects only??
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THE IPSILATERAL EYE
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Damage to the chiasm produces?
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Heteronymous defects
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Damage posterior to the chiasm produces what?
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HOMONYMOUS EFFECTS
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Constriction in response to light
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Miosis
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Afferents bypass -------- structure and enter the brachium of the supperior coliculus.
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LGN
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What 2 nerves are needed for the pupilary light reflex to occur?
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CN 2 and 3
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If either CN2 or CN 3 are damaged what happens to the reflex?
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It is abolished
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The direct reflex occurs in the eye that is stimulated by the light what is the reflex in the unstimulated eye?
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Consensual reflex
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In a patient with total blindness due to an afferent defect in one eye what can be elicited in the blind eye upon stimulation of good eye?
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Consensual pupillary contraction of bad eye due to stimulus of good eye.
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Blindness due to a lesion in the optic radiation or visual cortex will or will not cause a loss of the pupilary light reflex?
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Will not cause a loss of the pupillary light reflex
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Mydriasis=
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pupillary dilation
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Horner's syndrom has 3 characteristics what are they?
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Pupillary constriction due to paralysis of dilator pupillae muscle
Ptosis due to paralysis of SM of eyelid Flushed or dry skin |
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Horner's syndrom is the result of intereuption of what in the head?
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Sympathetic innervation in the head.
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Horner's syndromes are ipsilateral or contralateral to lesions? Symptoms?
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Ipsilateral.
Ptosis, flushing and dry skin due to vasodialtion and absence of sweating. Pupillary constriction |
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Accomodation Reflex=
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Near reflex
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Accomodation reflex is initated by what?
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Shift of gaze from far to near
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3 components of accomodation are?
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Ocular convergence, pupillary constriction, lens thickening
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Ocular convergenve involves?
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Contraction of medial recti to align image GSE
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Pupilary constriction does what?
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Constrictuor pupillae muscles contract to sharpen image GVE
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Lens thickening cause these muscles to contract? This allows for what?
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Ciliary muscle contracts, increase refractive power of the lens focusing on near object
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The efferent limb of the accomodation reflex?
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Oculomotor nerve
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Argyll Robertson pupil is what?
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Accomodates to near object but does not react to light
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Argyll Robertson pupil is also known as prostitutes pupil due to the ability to accomodate but not react and it is involved with which diseases?
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Tertiary syphilis, systemic lupus and DM
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Argyll Robertson pupil caused by?
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DM, tertiary syphilus, systemic lupus erthematosus
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