The eye Flashcards
What is the role of the cornea?
refracts light into the eye
what is the role of iris
controls how much light enters the pupil
what is the role of lens
refracts light, fine focusing into the retina
what is the role of retina?
it is covered in receptor cells which are used to detect light.
what are rods?
they are the receptor cells in the retina which detect dim light
what are cones?
they are receptor cells in the retina which detect different colours
what is the optic nerve
Carries impulses from the eye to the brain
what is the sclera?
it is the tough white outer layer of the eye and it prevents the eye from injury
How does your eye look at objects which are far away?
-the ciliary muscle relaxes, which allows the suspensory ligaments to pull tight
-this makes light less refracted
How does your eye look at objects which are close?
-the ciliary muscle contracts, which slackens the suspensory ligaments
-this makes light more refracted
what is short sightedness?
this is when people are unable to focus on far objects
-this is when light is refracted too much
-concave lenses can be used to correct it
what is long-sightedness
this is when people are unable to focus on close objects
this is when light isn’t refracted enough
convex lenses can be used to correct it
What is the pupil reflex?
This is a reflex arc which controls how much light enters the eye
What happens to the eye when it is in a dark room
-Radial Iris muscles contract
-Circular Iris muscles relax
-Pupil becomes dilated allowing more light to enter the eye
What happens to the eye when it is in a bright room?
-Radial muscles of Iris relax
-circular muscles of Iris contracts
-pupil contracts allowing less light
