visual system

Question 1

visual effects of loss of one hemisphere

Answer 1

neither eye can move to contralateral side or sees the contralateral environment

Question 2

fovea

Answer 2

center of the retina, area of most acute vision, projects to occipital lobe

Question 3

central scotoma

Answer 3

dark area in center of field of vision from optic neuritis in MS, macular degeneration, destruction of occipital poles

Question 4

medial longitudinal fasciculus lesion results

Answer 4

area located in pons, if damage, neither eye can look inward when looking to the side, but can converge (cross)

Question 5

vertical nystagmus

Answer 5

always abnormal, signifies a brain stem dysfunction

Question 6

doll’s eye phenomena

Answer 6

when you turn the head suddenly to one side, the eyes lag behind when there is no brain stem dysfunction

Question 7

deficits of cranial nerves caused by left hemisphere destruction

Answer 7

CN 1-loss of smell on left
CN2 right homonymous hemianopsia
CN3,4,6 loss of right conjugate gaze
CN5 right facial hemianesthesia
CN7 lower right facial paralysis
CN12 variable contralateral tongue paresis

Question 8

uncal herniation puts pressure on which CN

Answer 8

CN 3, leading to ptosis and oculomotor defects

Question 9

breathing patterns r/t various lesion locations

Answer 9

cerebrum- cheyne stokes-rapid then absent
midbrain- rapid
pons- slow, gasping
medulla-irregular rate and depth