Visual System

Question 1

The upper nasal visual quadrant projects to the ____

Answer 1

Lower temporal retinal quadrant

Question 2

The lower nasal visual quadrant projects to the ___

Answer 2

Upper temporal retinal quadrant

Question 3

The upper temporal visual quadrant projects to the __

Answer 3

Lower nasal retinal quadrant

Question 4

The lower temporal visual quadrant projects to the __

Answer 4

Upper nasal retinal quadrant

Question 5

Where do fibers from the temporal hemiretina and nasal hemiretina cross?

Answer 5

Fibers from temporal hemiretina do not cross in the optic chiasma
Nasal hemiretina fibers cross in the optic chiasma

Question 6

What is the rule of L’s?

Answer 6

Information from lower hemiretina projects to lateral part of lateral geniculate body, loop of Meyer, and lingual gyrus

Question 7

What do homonymous visual fields refer to?

Answer 7

Corresponding halves of visual fields such as temporal field of one eye and nasal field of other

Question 8

What do heteronymous visual fields refer to?

Answer 8

Noncorresponding visual fields like temporal field of one eye and temporal field of other

Question 9

What does a unilateral lesion of the optic nerve result in?

Answer 9

Monocular blindness

Question 10

What is binasal hemianopia?

Answer 10

Bilateral lesion of lateral aspect of optic chiasma
Results in hetronymous blindness in nasal fields of each eye
May also be unilateral since it is frequently due to atherosclerosis of internal carotid arteries

Question 11

What does a unilateral lesion of the lateral aspect of the optic chiasma result in?

Answer 11

Nasal hemianopia of ipsilateral eye

Question 12

What is bitemporal hemianopia?

Answer 12

May be due to midline lesion of medial portion of optic chiasma
Heteronymous deficit is usually caused by pituitary tumors

Question 13

What is contralateral homonymous hemianopia?

Answer 13

Result of unilateral lesions of lateral geniculate body, complete optic radiations, or visual cortex

Question 14

What is contralateral superior quadrantanopia?

Answer 14

Result of unilateral lesions of loop of Meyer

May be caused by tumor or infarction in posterior temporal lobe

Question 15

What is incongruent contralateral homonymous hemianopia with macular sparing?

Answer 15

Usually indicative of a unilateral lesion of visual cortex
May be due to obstruction of posterior cerebral artery
Lesions of visual cortex are usually incongruous (asymmetrical), whereas lesions of LGB or optic radiations are congruous in their visual field deficits

Question 16

The pretectum is important for the ___ reflex, while the posterior commissure is important for the ___ reflex

Answer 16

Direct light

Consensual light

Question 17

Describe accommodation

Answer 17

Cortically mediated visual response
Originates in frontal eye field of the frontal lobe
The triad of accommodation includes convergence of vision, pupillary constriction, and thickening of the lens

Question 18

What is Holmes-Adie Pupil (Tonic pupil)?

Answer 18

Benign condition, which may be due to lesion of ciliary ganglion
Initially, tonic pupil does not appear to react to convergence
If convergence is maintained for several seconds, the pupil will slowly constrict and will eventually be smaller than the normal pupil
It also constricts in response to parasympathomimetic agents, but the normal pupil does not

Question 19

What controls nonvolitional eye movements? Volitional eye movements?

Answer 19

Occipital eye field

Frontal eye field

Question 20

The visual projects __ image onto retinal field

Answer 20

Inverted and reversed