Final - Test 5. - Ch. 21 Visual System Flashcards
(33 cards)
What does sight mean?
recognition and location of objects
What degrees of vision does each eye have vertically and horizontally?
180 but facial structures get in the way
What cranial nn point eyeball where we want it to go?
3, 4, and 6
What does Cranial Nn III do?
Vision
BRING AP FROM LIGHT INFORMATION FROM THE EYES BACK TO THE BRAIN
What does Cranial N IV do?
PARASYMPATHETIC FIBERS THAT GO BACK TO THE PUPIL AND LENSE OF THE EYE
Eye movement
Control of pupil and lens
Cranial N IV?
Eye movement
Cranial nerve VI
Eye movement
What cranial n is considered the parasympathetic efferent?
II
Which Cranial nn are in charge of eye movement?
II, IV and VI
What visual field does the nasal retina see?
Temporal visual field on ipsilateral side
What visual field does the temporal retina see?
Nasal field on contralateral side
Where do axons from nasal retina cross midline?
optic chiasm
Which side of the occipital lobe do the axons from the nasal retina go?
contralateral side
Which side of the occipital lobe do the axons from the temporal retina go?
ipsilateral side
What passes through the thalamus on the way to the cortex?
Concious visual pathway
What does the tract for vision pass on the way to occipital lobe to turn head because of visual stimulus?
superior colliculus
What happens in the dorsal stream?
action
VISION GUIDES MOVEMENT
Comes into parietal to makes sense and ends in motor planning area
USE WHAT I SEE TO GUIDE MOTOR PLAN TO MOVE
What happens in ventral stream?
VENTRAL – USED FOR PERCEPTION - TO GIVE MEANING AND GIVE A NAME TO WHAT I SEE
COMES FROM OCCIPITAL LOBE DOWN TO INFERIOR TEMPORAL LOBE
MEMORIES STORED
VISUAL AGNOSIA
What is the pathway to the output specifying how to move (visual guidance)?
retina lateral geniculate visual cortex dorsal stream (action) posterior parietal cortex
What is the pathway to the output of visual identification of objects?
retina lateral geniculate visual cortex ventral stream (perception) occuipitotemporal region
What happens if a person has a single eye blindness?
optic N is cut
eye fills in gaps
loss of depth perception
contralateral eye can see 180 munis facial structures
Bitemporal hemianopsia
ONLY NASAL RETINA DAMAGED
BITEMPORAL HEMIANOPSIA – 2 TEMPORAL VISUAL FIELDS HALF VISION CANNOT SEE (TUNNEL VISION)
MOST COMMON WITH CVA
LOSS IN LATERAL PERIPHERAL VISION
AXONS FRON NASAL RETINAS CUT AT CROSSING – LOSS INT EMPORAL VISUAL VIELDS
Homonymous hemianopsia
ALL LIGHT INFORMATION FROM ONE HALF OF VISUAL SPACE GET CUT
LINE RIGHT DOWN MIDDLE
Quadrantanopsia
IN OPTIC RADIATIONS
ONE FOURTH DON’T SEE
AXONS THAT HAVE LEFT HALAMUS GET INTERUPTED ONLY UPPER AND LOWER
