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26 Cards in this Set
- Front
- Back
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what are the anatomical divisions of the optic nerves and where do they synapse first?
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the first part at the back of the retina where the ganglion cells all converge is the optic disc which becomes the optic nerve. The optic nerves from each eye will converge with each other at the optic chiasm; they then slit to the oprtic tracts and synapse in the lateral geniculate nuclei.
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what is another name for the optic disc?
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the blind spot bc it is all ganglion cell axons, no photoreceptor cells
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describe the path of the message of something seen in the lateral half of the visual field of the left eye.
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The image is inverted on the retina and thus signals on the nasal half of the retina. It will travel medially in the left optic nerve. Cross at the optic chiasm to the lateral part of the right optic tract and synapse in the right lateral geniculate body
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describe the path of the message of something seen in the nasal half of the visual field of the right eye.
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The image signals on the lateral part of the retina and thus follows the lateral part of the right optic nerve and stays lateral in the chiasm to follow the lateral part of the right optic tract and synapse in the righ lateral geniculate body.
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the right half of each visual field will project to which lateral geniculate body?
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the left
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what is the relationship between retinal fields and visual fields?
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they are inverted. (left for visual is right for retinal; up for visual is down for retinal)
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what seperates the occipital from the parietal lobe? the cuneate gyrus from the lingula gyrus?
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the parieto-occipital sulcus, the calcarine fissure
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where is the primary visual cortex located and what is another name for it? why? what brodman's area is it?What does it do in terms of visual processing?
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along the calcarine fissure in cuneate and lingual gyrus. It is AKA striate cortex bc of alternating gray and white matter. IT is #17. it detects color, shade, size, shape, direction, and movement of the object perceived.
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the essential parts of vision are processed where?
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in the retina
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how does a message get to the secondary and tertiary visual corticies?
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via projections from the primary cortex
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what does the secondary visual cortex do?
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it is more involved with identification, ex. the concept of a person as a student, man, women...
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what is the function of the tertiary visual cortex?
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to form ideas from an image and recognition, like interpreting lines and symbols into words and letters
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neurons leaving the geniculate body take a path to the visual cortex on what side of the brain? what is this path called?
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ipsilateral side, they have a few names: geniculocalcarine tract, optic radiations or geniculostriate tract.
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the occipital pole interprets vision from where?
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the fovea centralis
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what lamina of the lateral geniculate body receive ipsilateral axons? contralateral?
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2,3,5;1,4,6
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describe bilateral heteronymous hemianopsia.
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both eyes are affected, but only the right side of one eye and the left side of the other eye
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describe homonomous hemianopsia.
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that is a defect in the left visual field of both eyes or the right visual field of both eyes
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If the artery that supplies the left cuneate and lingual gyrus is compromised what deficit happens and why?
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right homonomous hemianopsia would occur but with macular sparing bc the occipital pole is in a watershed area that has branches from the middle cerebral. Our original occluded artery came from the posterior cerebral
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Describe a contra-coup injury and its effects.
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Usually happens in car accidents when the brain is slammed into the frontal part of the head and then rebounded back into the occipital portion thus damaging the occipital pole. Thus the macula is damaged. ppl have peripheral vision but not the central vision, thus they cannot read or see detail.
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What is the path of meyer's loop from the LGB? What messages are contained in these paths?
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from the LGB under the ventricals through the temporal lobe to the occipital lobe. Upper visual field messages (lower retinal field) are contained in these pathways.
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damage to the left meyer's loop would result in what?
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upper right quadrantanopsia AKA "pie in the sky."
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what will happen if light is shined in the right eye? What is this called?
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parasympathetics will constrict the pupil in BOTH eyes. The right eye will exhibit the direct pupillary light reflex while the left eye exhibits the consenual pupillary light reflex
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where do the pupillary light reflexes synapse?
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in the edinger westphal nucleus
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what nerve provides the sensory information for the pupillary light reflex to occur? What nurve makes the pupillary muscle constrict?
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optic nerve which has fibers that project from the lateral geniculate nucleus to the edinger westphal nucleus. The occulomotor nerve makes the pupillary muscle constrict.
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what makes the consensual pupillary reflex possible?
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the posterior commisure allows the collaterals to go to the contralateral side to the edinger westphal nucleus.
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What pathology might cause deficits in the consensual reflex but not the direct reflex?
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A pineal tumor since it is located right above the posterior commisure.
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