Ch. 16: Vestibular and Visual Systems Flashcards
1
Q
Lesions to optic Radiations
A
- hemianopsia or quadrantanopsia
- loss of info from contralateral visual field
2
Q
Lesion to optic chiasm
A
- bitemporal hemianopsia
- loss of info from both temporal visual fields
- interruption to axons of nasal half of each retina
3
Q
Lesion to optic tract
A
- homonymous hemianopsia
- loss of visual info from one visual hemi-field
4
Q
Lesion to optic nerve
A
- blindness
- ipsilateral eye
5
Q
Hair cells
A
- inside base of canals in fluid
- at rest, send certain # action potentials
- bent one way=increase #
- benth other way= decrease #
6
Q
canals & vision
A
- inner ear connected to eye movement
- stabilize vision when head is moving
7
Q
semicircular canals
A
- anterior=45*
- posterior=45*
- horizontal=tipped 30* (ant more superior)
8
Q
paired activity
A
-increased action potential # toward side of rotation and decreased proportionately on complementary side
- Complimentary sides:
- -horizontal-horizontal
- -L ant-R post
- -R and-L post
9
Q
otolithic organs
A
- base of canals (hair cells in gel with rocks on top)
- respond to linear movement and pull of gravity
- modulate postural muscle activity in response to movement or gravity
10
Q
Input to vestibular nuclei
A
- collect info from every sensory system that senses movement
1. vestibular info
2. visual info
3. proprioceptive info
4. tactile info
5. auditory info
11
Q
outputs from vestibular nuclei
A
- medial vestibulospinal tract (helper neurons)
- lateral vestibulospinal tract (helper neurons)
- spinal accessory nerve IX
- cerebral cortex
- medial longitudinal fasciculus
- reticular formation (nausea/vomiting)
- cerebellum
12
Q
superior colliculus
A
- reflexive head movements in response to vision
- orientation and visually guided eye movement
13
Q
L Visual Cortex sees:
A
Right visual field
14
Q
R visual cortex sees:
A
L visual field
15
Q
Dorsal Action Stream
A
- light from occipital cortex to motor planning area
- visually guide movements