2A: Early Vision Flashcards
1
Q
Electromagnetic Radiation
A
- Oscillation (waves) of electrically charged particles - A small range of wavelengths constitute visible light
2
Q
What is a wavelength?
A
- distance between peaks (nm) - gives rise to the perception of color
3
Q
What is Amplitude?
A
- height of peaks - gives rise to intensity (brightness)
4
Q
What does it mean to absorb, reflect, or transmit light?
A
- Depends of properties of the object - Our visual experience is based on the light reflected off of objects (and into the eye)
5
Q
Parts of the Eye
A
6
Q
What are the Two Chambers of the Eye?
A
- Anterior chamber - filled with aqueous humor.
- Vitreous chamber - filled with vitreous humor
7
Q
Iris/Pupil
A
Changes size to allow more or less light inside the eye
8
Q
Cornea v. Lens
A
Cornea
- bends (refracts) incoming light to focus on retina
- non-flexible
Lens
- flexible transparent convex disk that also refracts light
- performs accommodation: adjusting its shape to change depth of focus
9
Q
Retina
A
- Light sensitive membrane on the back of the eye that performs sensory transduction
- Contains photoreceptors
10
Q
fovea
A
- central region of the retina directly across from the pupil
- corresponds to your fixation point
11
Q
periphery
A
- All other regions of the retina around the fovea
12
Q
Optic Disc/Blind Spot
A
- Specific location in the periphery where blood vessels enter the eye, and neural fibers exit
- no photoreceptors
13
Q
Retinal Image
A
- Distribution of light on the retina corresponding to the visual scene or environment
- Influenced by: eyeball shape,quality of lens,shape of cornea
14
Q
The Retina: 3 Layers
A
- Photoreceptors
- Bipolar cells
- Ganglion cells (RGCs)
15
Q
What are photoreceptors?
A
- Contain photopigments - light-sensitive molecules
- four subtypes - each maximally sensitive to different wavelengths
16
Q
Wha is a Graded Potential?
A
- Light stimulation causes a proportional decrease in NT release (glutamate)
17
Q
Cones
A
- Three pigment types (used for color)
- Low sensitivity
- Mostly in the fovea
18
Q
Rods
A
- One pigment type
- High sensitivity
- Mostly in periphery
19
Q
Bipolar Cells
A
20
Q
Midget bipolar cells
A
- Mostly in fovea
- Receive input from single cones
- Low convergence
- Pass information to single RGCs
21
Q
Diffuse bipolar cells
A
- Mostly in the periphery
- Receive input from many photo- receptors (mostly rods)
- High convergence
- Pass information to few RGCs
22
Q
How do Midget and Diffuse Bipolar cells react to glutamate?
A
- Some are inhibited by glutamate: ON midget bipolar cells
- Others are excited by glutamate: OFF midget bipolar cells
