the eye
function of choroid
black to absorb light
function of cornea
-transparent to allow light through
-refracts light
function of conjunctiva
protect cornea
function of retina
contains light sensitve cells
-rod and cone receptor cells
function of optic nerve
transports impulses to brain from rod and cone cells in the retina
function of iris
-mucles changes size of pupil
-to control light entering
function of ciliary muscles
-attatch suspensory ligaments to eye
-contract and relax to make suspensory ligamnts go slack or tight
function of lens
changes shape to focus light onto retina
function of sclera
tough to hold shape of eye
function of fovea
most sensitve part,clear image produced
function of suspensory ligaments
-attach lens to cilary msucles
-slacken or tighten to change shape of lense
where is the light bent
cornea and lens
what happens in bright light
-BRRCC
-RADIAL MUSCLES RELAX and CIRCULAR MUSCLES CONTRACT
-to narrow pupil
-less light enters
-protects retina from damage
what happens in dim light
-DRCCR
-RADIAL MUSCLES CONTRACT and CIRCULAR MUSCLES RELAX
-to widen pupil
-allows more light in
-to help a person see in the dark
what happens when looking at distant object
-ring of cililary muscles relax
- lens pulled into thin shape
-bends light slightly
-image formed on retina
what happens when looking at near object
-ring of cilary muscles contract
- lens become rounder
-bend light greatly
-image formed on retina