eye Flashcards
cornea
a dome-shaped transparent layer continuous with the sclera. it refracts light rays into the eye
aqueous chamber
filled with aqueous humour, a transparent watery fluid
keeps front of eyeball firm and refracts light into pupil
lens
transparent, circular biconvex structure
elastic and changes it shape or thickness in order to focus light on the retina
retina
innermost layer of the eye
contains photoreceptors
blind spot
region where optic nerve leaves the eye
optic nerve
a nerve that transmits nerve impulses to the brain when photoreceptors are stimulated
fovea
a small yellow depression in the retina
where images are focused
greatest conc of cones, but no rods
vitreous chamber
contains vitreous humour, a transparent jelly-like substance
helps to keep eyeball firm
refract light onto retina
choroid
middle layer of eye
pigmented black to prevent internal refraction of light
contains blood vessels that bring oxygen and nutrients to the eyeball and remove metabolic waste produced
pupil
allows light to enter eye
conjunctiva
secrets mucus to keep front of eyeball moist
eyelashes
shield eye from dust particles
tear gland
secretes tears to
wash away dust particles
keep cornea moist
lubricate conjunctiva
eyelids
protect cornea from mechanical damage
squinting prevents excessive light from entering
spreads tears over cornea
