6.1b - Human Vision

what do tear glands contain

salt water

purpose of tears

salt will suck out water from germ cells and moistens your eye to prevent drying

what do tear glands do every time you bilnk

add new salt water and drain old salt water

what happens when you cry

your muscles contract which forces the tear galnds to shoot out water

is the image received at the retina upright or upside down

upside down

what is the light first refracted by before entering the pupil

cornea and aqueous humour

what does the light go through after entering the pupil

lens

what happens to the light after passing through the lens

light rays converge at focal point

why do we see things right side up

the brain automatically brings the image right side up

how do you know the focal point is exactly on the retina

the image is focussed

why does the optic nerve cross over to the other side of the brain midway

the right hemisphere of the brain controls the left side of the body and vice versa

what is the point where the optic nerves cross over called

optic chiasma