Visual System Flashcards
What is the preferred sensory modality in humans?
Vision
What are the 2 components of the visual system?
Sensory and motor
What are the individual parts of the visual sensory system?
Sensation, central pathway, and perception
What is the visual motor system responsible for?
Positioning the receptors to capture and maintain the desired visual target
Perception can change even when…
the image on your retina is constant
Perception is not a replica of the retinal image, its…
an interpretation of visual information arriving at V1
What does the anterior chamber of the eye contain?
The aqueous humor, iris, lens, and ciliary muscles
What does the posterior chamber of the eye contain?
The vitreous humor, retina, optic disk, optic nerve, choroid, and sclera
What does the retina contain?
Macula lutea, fovea centralis, nasal hemiretina, and temporal hemiretina
What type of cells are first order neurons of the visual system?
Bipolar cells
What type of cells are second order neurons of the visual system?
Ganglion cells
Characteristics of rods
Motion detectors, low resolution, detect black/white, 120 million
Characteristics of cones
Color detectors, rgb, 6 million
When are rods most useful?
At night, thus very sensitive to light
Where are rods most concentrated?
Toward the periphery
Where are cones most concentrated?
Towards the center
Characteristics of temporal hemiretina
Image remains uncrossed in central vesiual pathway
Characteristics of nasal hemiretina
Image crosses at the optic chiasm
What does a lesion posterior to the optic chiasm lead to?
Hemianopia
What does a lesion anterior to the optic chiasm lead to?
Monocular blindness
What are the 3rd order neurons of the visual system?
Optic radiations
What are the components of the visual motor system?
Motor control centers of the brain, 3 cranial nerves, and 6 extra-ocular muscles
What are the motor control centers of the brain?
The cortical and brain stem centers
What are the cortical eye centers of the brain?
Frontal eye fields and occipitoparietal eye fields
What are the brainstem eye centers of the brain?
The superior colliculus
