Vision Flashcards
What do we see?
only objects that light reflects on (light is a form of electromagnetic ray)
the visible spectum
very narrow span of electromagnetic waves that human respond to
How do we see? (order of what part light hits first)
cornea, pupil, iris, lens, retina, rods&cones
Cornea
protective layer, transparent, bends light ray inwards and pulls it through pupil
Pupil
opening in center of iris (hole), responds to emotions (attraction=pupil larger, lying, scared=pupil larger, intense mental activity)
Iris
-colored
-muscles in iris dilate/contract pupil (regulates light coming in)
Lens
-lens focuses image onto the retina
-focus on close objects=lens bulges, focus on far=lens flattens. This is called ACCOMODATION. *with old age, lens becomes less flexible which makes it easier to see from far than close
Retina
Sensory receptor for vision, center of retina=Fovea (where image is focused)
Rods & Cones
-the retina’s receptor cells
-cones: color, fine detail, work in bright light
-rods: focus on black&white, work in dim light, helps adapt to dark/bright places
-TRANSDUCE light waves into neural impulses
Where does transduction happen + path of neural impulse
-in the retina, because of rods and cones
-impulses are fed to ganglion cells(cables) that leave eye to go to brain which form the Optic Nerve
-the nerve crosses the opposite sides of the brain at the optic chiasm
-There is a blind spot on that nerve where there are no rods and cones
Trichromatic color theory
3 cones in retina, each espond to green, blue, red
Opponent-process color theory
cells increase/decrease rate of firing when different colors are presented (ex: red&green together)
color-blindness stats
7% of males vs 1% of females, because vision carries on x chromosome, most common difficulty is red from green
