Visual Perception Flashcards
cornea
outer layer of eye
pupil
opening at center of the iris
When does the pupil dilate?
When dark, opens to increase amount of light into the eye
When does the pupil constrict?
When bright, shrinks to decrease amount of light in the eye
What is the function of the iris?
adjust size of pupil to control amount of light
Parasympathetic component is when
pupils dilate with nervousness
What is the lens?
Helps focus light via changing shape
What are binocular cues?
Use of both eyes/convergence
How many layers of the retina are there?
10
What is the action potential in the eye?
transduction
What is the macula responsible for?
specific details such as
* text on page
* differences between faces
* tiny movements
* specific colors
When macula function is lost, what happens?
Blurriness
Describe the fovea.
Place of highest visual acuity level, cones are concentrated here, center of gaze. No rods here.
Where is the fovea located?
small pit inside of macula, .35mm
Why do we move our head and eyes to see?
Placing objects in front of the fovea to line it up
Movement of stimuli sequence…
- Light hits photoreceptors
- Interacts molecule - photo pigment
- Initiates chain events - prorogates the visual signal
- Bipolar Cells – receive action potential from cones & rods, in turn will activate ganglion cells,
- Ganglion cells leave eye in large cluster - Optic Disc
Describe the optic disc?
-contains no photoreceptors
-cannot process any visual information
-natural blind spot, do not notice because surrounding photoreceptors & info from the other eye to fill in (closure)
Ganglion cells become _____ when they leave the retina
optic nerve
Function of optic nerve?
carries visual info to brain to be processed
Photoreceptors induce graded potential in response to light to dark and vice versa causing ____?
Increase/decrease of glutamate
Starting at retina, there is coding for what 3 things?
color
shape
movement
2 areas that cross at the optic chiasm?
nasal and temporal
Which area is in the nasal portion of optic chiasm?
refers to the portion of the eye closest to the nose
Which area is the temporal portion of optic chiasm?
refers to the portion of the eye closest to temple
After optic chiasm visual fibers are no longer called optic nerve they now known as _______
_________
optic tract
Where does most of the optic tract travel to?
thalamus, but not smell!
What is the thalamus?
relay system that send the signal outward to appropriate location.
Direction of the optic tract?
1.enters thalamus at lateral geniculate nucleus (LGN) –
2. sends signal to primary visual cortex (within occipital lobe)
–where interpretation of signal occurs