QUESTIONS AND SOLUTIONS RATED A+
✔✔Lens Curvature - ✔✔close object --> lens is fatter/rounder
far object --> lens is elongated (focuses object near back of eye)
✔✔Vitreous Humor - ✔✔clear, jelly-like substance that comprises the main chamber
inside eyeball
✔✔Retina - ✔✔neural tissue lining the back of the eye where light is translated from a
physical stimulus to a neural signal
made up of neural cells arranged in 3 layers:
1. Photoreceptor Cells
2. Bipolar Cells
3. Ganglion Cells
✔✔Photoreceptors - ✔✔very back of the eye that translates physical stimulus of light
into neural signals
✔✔Retinal Pigment Epithelium (RPE) - ✔✔where photoreceptors get their nutrients
from
✔✔Cones - ✔✔used for day and high light intensity vision that allow us to see in colour;
about 6 million; offer good visual acuity (share a more direct link with ganglion cells than
rods do), sharpness of detail, and concentrated towards fovea
✔✔Fovea - ✔✔tiny spot in the middle of the retina that contains exclusively cones;
when we want to see something in detail, we move our eyes so the image falls directly
on the fovea
✔✔Rods - ✔✔used for night and low light intensity vision that provide no colour
information; 125 million; offer poor visual acuity, concentrated in periphery (surrounding
fovea) so it's better to look slightly to one side when area is dimly lit
✔✔Ganglion Axons - ✔✔converge on optic disc; exit hole for ganglion axon
✔✔Blind Spot - ✔✔on the optic disc because it lacks photoreceptors
✔✔Horizontal and Amacrine Cells - ✔✔cells in retina that allows areas within a retinal
layer to communicate with each other
- allow information from adjacent photoreceptors to combine
✔✔horizontal cells - ✔✔type of cell that receives input from receptors and delivers
inhibitory input to bipolar cells
,✔✔amacrine cells - ✔✔Specialized retinal cells that contact both the bipolar cells and
the ganglion cells, and are especially significant in inhibitory interactions within the
retina
✔✔Receptive Field - ✔✔collection of rods and cones in retina that affect the firing of a
particular ganglion cell when stimulated
✔✔Right Visual Field - ✔✔visual input travels to left hemisphere
✔✔Left Visual Field - ✔✔visual input travels to right hemisphere
✔✔Inner Eye Axons - ✔✔have to cross over to the opposite hemisphere
✔✔Optic Chiasm - ✔✔point at which optic nerves from the inside half of each eye cross
over to the opposite hemisphere
✔✔Main Pathway - ✔✔most retinal and ganglion cells travel through this pathway
✔✔Primary Visual Cortex (V1) - ✔✔Occipital Lobe; proceses visual information and
receives visual input from the retina; Topographical Organization of Visual Space
✔✔Extrastriate Cortex - ✔✔visual processing areas in occipital lobe outside of the
striate cortex
✔✔Topographic Map - ✔✔neighboring locations in the retina project to neighboring
locations in visual cortex
✔✔Dorsal Stream - ✔✔the "where" pathway; extrastriate cortex to parietal lobe;
processes depth and motion
✔✔Ventral Stream - ✔✔the "what" pathway; extrastriate cortex to temporal lobe;
processes colour and form
✔✔Information Compression - ✔✔visual information is compressed as it is processed
along its pathway
✔✔Cumulative Selection - ✔✔evolutionary process where new adaptations are layered
upon old adaptations
✔✔Light Sensitive Patch - ✔✔a patch of cells that is sensitive to receive input from light;
jellyfish, worms
✔✔Curved "Cup" Eye - ✔✔light sensitive patch that can sense direction of light; clams
, ✔✔Crude Lens - ✔✔can identify visual input from different distances
✔✔Image Forming Eyes - ✔✔1. Compound eyes
2. Simple eyes
✔✔Compound Eyes - ✔✔good at detecting movement but only at close distances;
anthropods (insects/crabs); made of ommatidia
✔✔Ommatidia - ✔✔individual tubular units that each point in slightly different location to
detect light right in front of it
✔✔Simple Eyes - ✔✔varied design (size, location) and contain eyeball, lens, retina;
vertabrates and mollusks (octopus, squid)
✔✔Large Eyes - ✔✔result in higher visual acuity and/or higher sensitivity
- ex. hawks, humans --> good resolution
- ex. cats, horses, owls --> good sensitivity
- ex. deep sea animals --> both
✔✔Lateral Eye Placement - ✔✔found in prey animals; offer a wide field of view with
very little overlap in visual fields; low depth perception
✔✔Forward Eye Placement - ✔✔found in predators; offer a narrow field of view with lot
more binocular overlap; very good depth perception
✔✔Development of Vision Fetal/New Born - ✔✔As a fetus, eyes form during 2nd month
of pregnancy and react to light at 6th month; organized wiring
New Borns have weak lens muscles that limits how well babies can focus
✔✔Development of Vision 3 months - ✔✔ability to focus has improved to almost adult-
like
✔✔Development of Vision 6 months - ✔✔visual acuity is improved
✔✔Development of Vision 1 year - ✔✔acuity is close to adult levels
✔✔Development of Vision 4 years - ✔✔retinal cells reach adult-like levels; reach full
adult acuity
✔✔Development of Vision 11 years - ✔✔optic nerve and visual cortex are completed;
development "fully" complete