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Flashcards in VISUAL SYSTEM Deck (28)
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1. Interruption of the medial longitudinal fasciculus (MLF) at pontine levels
A. results in miosis and ptosis
B. results in paralysis of upward gaze on command
C. results in paralysis of lateral gaze on command
D. abolishes convergence
E. abolishes accommodation

1-C Interruption of the pontine medial longitudinal fasciculus (MLP) results in a medial rectus palsy on attempted conjugate lateral gaze. Convergence remains intact. This syndrome, called internuclear ophthalmoplegia (INO) or medial longitudinal fasciculus (MLF) syndrome, is commonly seen in multiple selerosis.

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2. A 75-year-old coal miner complains of progressive loss of vision. Visual field examination shows visual loss in the upper right quadrant in both visual fields. The lesion would most likely be in the
A. right angular gyrus D. right occipital pole
B. left cuneus E. right lingual gyrus
C. left temporal lobe

2-C Ablation of the anterior temporal lobe destroys the visual radiations that project to the lower bank of the calcarine sulcus. The fiesld deficit is an upper right homonymous quadrantanopia, which is also called Meyer loop quadrantanopia.

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3. All of the following statements concerning the optic chiasm are correct EXCEPT
A. its primary blood supply is from the anterior cerebral and internal carotid arteries
B. it lies dorsal to the diaphragm sellae
C. the midsagittal section results in binasal hemianopia
D. it contains uncrossed fibers from the temporal hemiretinae
E. it contains papillary fibers en route to the pretectum

3-C The midsagittal seetion of the optic chiasm transects fibers from the nasal hemiretinae, resulting in a bitemporal hemianopia.

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4. All of the following statements concerning the lateral geniculate hoby (LGB) are correct EXCEPT
A. it is a thalamic nucleus
B. it receives input from the contralateral visual field
C. it is irrigated by the posterior cerebral artery and the anterior choroidal artery
D. destruction results in bitemporal hemianopia
E. it projects to the lingual gyrus and the cuneus

4-D Destruction of the optic tract, the lateral geniculate body (LGB), or the geniculocalearine tract all result in the same visual field defect, a contralateral homonymous hemianopia.

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5. All of the following statements concerning the visual cortex are correct EXCEPT
A. it corresponds to area 17
B. it is located on the banks of the calcarine suleus
C. destruction of the upper hank of the calcarine sulcus results in a lower ipsilateral homonymous quadrantanopia
D. cortical lesions are characterized by macular sparing
E. it is irrigated by a branch of the posterior cerebral artery

5-C Destruction of the upper bank of he calearine suleus interrupts lateral geniculate body (LGB) fibers, which represent the upper ipsilateral retinal quadrants. The field defect is called a lower contralateral homonymous quadrantanopia.

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6. All of the following statements concerning the papillary light pathway are correct EXCEPT
A. transaction of the optic tract eliminates the direct papillary light response
B. transaction of the optic nerve would not eliminate the consensual papillary light reflex
C. destruction of the lateral geniculate body (LGB) would not interrupt the papillary light pathway
D. the efferent limb of the pupollary light reflex is the oculomotor nerve (CN III)
E. axons of the retinal ganglion cells mediating the pupillaty light reflex terminate in the pretectal nucleus

6-A Transection of the optic tract would not eliminate the direct pupollary response. Papillary fibers in the optic tract project ot the pretectal nuclei, which diseharge to the ipsilateral and contralateral Edinger-Westphal nuclel.

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7. All of the following statements concerning the superior colliculus are correct EXCEPT
A. it is the lectum of the midhrain
B. it receives input from the retina and visual cortex
C. it plays a role in head and eye movements
D. it is irrigated by the posterior communicating artery
E. a unilateral lesion results in contralateral negleet of visual stimull

7-D The superior colliculus is irrigated by the long circumflex branches of the posterior cerebral arteries (quadrigeminal arterics)

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8. All of the following statements concerning the retina are correct EXCEPT
A. it is derived from the optic vesicle of the diencephalon
B. it is sensitive to wavelengths from 400 nm to 700 nm
C. retinal ganglion cells project directly to the visual cortex
D. retinal ganglion cells project directly to the hypothalamus
E. retinal ganglion cells project directly to the midbrain

8-C Retinal ganglion cells project to the lateral geniculate body (LGB), which projects to the primary visual cortex. Retinal ganglion cells project directly to the suprachiasmatic nucleus of the hypothalamus and to the pretectal nuclei and superior coliculus of the midbrain. The retina is derived from the optic vesicle of the diencephalon

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9. All of the following statements concerning the optic disk are correct EXCEPT
A. it is found nasal to the fovea centralis
B. it is the blind spot
C. it contains the retinal vessels
D. it contains myelinated axons from the ganglion cell layer
E. it contains neither rods nor cones

9-D The optic disk, the optic papilla, is found nasal (medial) to the fovea centralis. It contains no rods or cones and thus represents a blind spot in the retina. The retinal vessels emerge from the optic disk. Myelinated axons usually are not found in the retina : when they are present, they may produce a central acotoma. Myelination of the optic nerve extends from the external part of the lamina cribrosa to the lateral geniculate body (LGB)

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10. All of the following statements concerning the fovea centralis are correct EXCEPT
A. it plays a role in photopic vision D. it is the optic papilla
B. it lies within the macula lutea E. it is the site of highest visual acuity
C. it contains only cones

10-D The fovea centralis lies within the macula lutea and represents the locus of highest visual acuity. The fovea contains only cones, thus subserving color or day (photopic) vision. The fovea centralis lies temporal (lateral) to the optic disk. The optic disk is the optic papilla.

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11. All of the following statemens concerning the ganglion cells of the retina are correct EXCEPT
A. they give rise to the optic nerve
B. they receive direct input from the rods and cones
C. they are derived from the diencephalon
D. they project to the lateral geniculate body (LGB)
E. they project directly to the hypothalamus

11-B The ganglion cells of the retina give rise to the optic nerve and project to the lateral geniculate body (LGB), the hypothalamus, the pretectal nucleus, and the superior colliculus. Input from the rods and cones is conducted to the ganglion cells via the bipolar cells. The retina is derived from the optic vesicle of the diencephalon. The hypothalamic projection is to the suprachiasmatic nucleus, a circadian pacemaker.

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12. All of the following statements concerning the optic nerve are correct EXCEPT
A. it is a myelinated tract of the central nervous system (CNS)
B. it is a true peripheral nerve
C. it is investerd by leptomeninges
D. it is ineapable of regeneration
E. its cells of origin are found in the ganglion cell layer of the retina

12-B The optic nerve is a myelinated tract of the central nervous system (CNS) that is invested by the leptomeninges and the dura meter. Its cells of origin are found in the ganglion cell layer of the retina. It is incapable of regeneration

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13. All of the following statements concerning the subcortical center for lateral gaze are correct EXCEPT
A. it receives input from the contralateral frontal lobe
B. it projects to the contralateral medial longitudinal fasciculus (MLF)
C. it is found in the pons
D. it is found in the midbrain
E. it is found within a cranial nerve nucleus

13-D The subcortical center for lateral gaze is found in the abdocend nucleus of the pons, receives input from the contralateral frontal eye field (area 8), and projects to the contralateral medial longitudinal fasciculus (MLF). Destruction of the abducent nucleus results in a ipsilateral lateral reetus paralysis and a contralateral medial rectus palsy on attempted lateral gaze. The subcortical center for vertical conjugate gaze is located in the midhrain at the level of the posterior commissure.

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A. Bitemporal hemianopia
B. Binasal hemianopia
C. Left upper homonymous quadrantanopia
D. Right lower homonymous quadrantanopia
E. Left homonymous hemianopia

14. Transection of
the right optic tract

14-E Transection of the right optic tract results in a left homonymous hemianopia

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A. Bitemporal hemianopia
B. Binasal hemianopia
C. Left upper homonymous quadrantanopia
D. Right lower homonymous quadrantanopia
E. Left homonymous hemianopia

15. Transection of
the right Meyer loop

15-C Transection of the Meyer loopo on the right side results in a left upper quadrantanopia (“pie in the sky”). The Meyer loop is the inferior geniculocalearine pathway that conveys information from the inferior retinal quadrants to the inferior bank of the ealcarine sulcus, the lingual gyrus.

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A. Bitemporal hemianopia
B. Binasal hemianopia
C. Left upper homonymous quadrantanopia
D. Right lower homonymous quadrantanopia
E. Left homonymous hemianopia

16. Midsagittal section of
the optic chiasm

16-A A midsngittal section of the optic chiasm interrupts the decussating fibers from the nasal hemiretinae and results in a bitemporal hemianopia

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A. Bitemporal hemianopia
B. Binasal hemianopia
C. Left upper homonymous quadrantanopia
D. Right lower homonymous quadrantanopia
E. Left homonymous hemianopia

17. Tumor of
the right lateral geniculate body (LGB)

17-E A lesion of the right lateral geniculate body (LGB) produces a left homonymous hemianopia. A lesion of the optic tract, the LGB, or the visual pathway all produce the same fiels deficit, a contralateral homonymous hemianopia.

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A. Bitemporal hemianopia
B. Binasal hemianopia
C. Left upper homonymous quadrantanopia
D. Right lower homonymous quadrantanopia
E. Left homonymous hemianopia

18. Pituitary tumor

18-A A pituitary tumor most commonly produces a bitemporal hemianopia. The pituitary (hypophysis) gland lies ventral to the optic chiasm

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A. Bitemporal hemianopia
B. Binasal hemianopia
C. Left upper homonymous quadrantanopia
D. Right lower homonymous quadrantanopia
E. Left homonymous hemianopia

19. Tumor of the left cuneus

19-D Destruction of the left cuneus produces a right lower homonymous quadrantanopia. Upper retinal quadrants project ot the upper banks of the calcarine sulcus

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A. Bitemporal hemianopia
B. Binasal hemianopia
C. Left upper homonymous quadrantanopia
D. Right lower homonymous quadrantanopia
E. Left homonymous hemianopia

20. Trauma to
the right lingual gyrus

20-C Destruction of the right lingual gyrus produces a left upper homonymous quadrantanopia. Lower retinal quadrants project to the lower banks of the calcarine sulcus.

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A. Bitemporal hemianopia
B. Binasal hemianopia
C. Left upper homonymous quadrantanopia
D. Right lower homonymous quadrantanopia
E. Left homonymous hemianopia

21. Bilateral lateral constriction of
the optic chiasm

21-B Bilateral constriction of the optic chiasm damages the nondecussating fibers from the temporal hermiretinae and roduces a binasal hemianopia

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A. Anisocoria
B. Argyll Robertson pupil
C. Fixed dilated pupil
D. Horner syndrome
E. Marcus Gunn pupil

22. Results from interruption of
the cervical sympathetic trunk

22-D Horner syndrome results from interruption of the cervical sympathetic trunk

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A. Anisocoria
B. Argyll Robertson pupil
C. Fixed dilated pupil
D. Horner syndrome
E. Marcus Gunn pupil

23. Is present in 10% of
the population

23-A Anisocoria, unequal pupils, is present in 10% of the population

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A. Anisocoria
B. Argyll Robertson pupil
C. Fixed dilated pupil
D. Horner syndrome
E. Marcus Gunn pupil

24. Is characterized by
uncal herbiation

24-C In transtentorial herniation, the hippocampal uncus is forced by increased pressure (brain tumor) through the tentorial incisures. Pressure on the oculomotor nerve (CN III) results in a fixed dilated pupil, and an eye that “looks down and out,” Pressure on the basis pedunculi, affecting the corticospinal tracts, results in a contralateral hemiparesis.

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25. Is characterized by the absence of the miotic reaction to light but with the presence of the miotic reaction to near stimulus
A. Anisocoria
B. Argyll Robertson pupil
C. Fixed dilated pupil
D. Horner syndrome
E. Marcus Gunn pupil

25-B The Argyll Robertson pupil is characterized by the absence of the miotic reaction to light but with the presence of the miotic reaction to near stimulus

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26. The pupil dilates when light is shined from the normal pupil into the afferent pupil.
A. Anisocoria
B. Argyll Robertson pupil
C. Fixed dilated pupil
D. Horner syndrome
E. Marcus Gunn pupil

26-E The Marcus Gunn pupil is an afferent pupil, with a lesion in the afferent limb of the pupillary light pathway

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A. Anisocoria
B. Argyll Robertson pupil
C. Fixed dilated pupil
D. Horner syndrome
E. Marcus Gunn pupil

27. Is frequently seen in
multiple selerosis

27-E The Marcus Gunn pupil is commonly seen in multiple sclerosis

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A. Anisocoria
B. Argyll Robertson pupil
C. Fixed dilated pupil
D. Horner syndrome
E. Marcus Gunn pupil

28. is associated with
syphilis

28-B The Argyll Robertson pupil is associated with neurosyphilis