the eye Flashcards
what is the part of the eye that the light will hit first
the cornea
features of the cornea
transparent - to allow light to pass through
what is the purpose of the cornea
causes all the light that passes through it to refract
what does the pupil do
its a gap in the middle of the iris that allows light to pass through to go to the lens
what does the iris do
its the coloured part of the eye
it controls hoe big/small the pupil is
what does the lens do
it bends/ refracts light
it can change its shape, which allows it to control how strongly it refracts the light, so it can focus the light directly onto the retina
what are the two types of receptor cells in the retina
rod cells
cone cells
what do cone cells do
they allow us to see in colour because they are sensitive to the colour of light
what type of light do cone cells not work well in
low light
what do rod cells do
only allow us to see in black and white so work better in low light
why cant you see colours when its dark
its only the rod cells that are working
what does the optic nerve do
takes all the impulses generated by receptor cells and transmits them to the brain
what is the fovea
a spot on the retina where there are only cone cells
it helps to see as clearly as possible
What happens to the eye when looking at a bright light
the pupil is constricted
circular muscles contract
radial muscles relax
what happens to the eye when looking at a low light
the pupil dilates
circular muscles relax
radial muscles contract
