SB2h - The eye Flashcards
Name the 7 parts the eye consists of.
pupil
Iris
Lens
Cornea
Optic nerve
Retina
Ciliary
muscle
What does the iris do?
Controls how much light enters the pupil (dilate and constrict)
What does the Optic nerve do?
Carries electrical impulses from the eye to the brain
What does the Lens do?
Light passes through it It bends/refracts light so it focuses onto the retina
What does the Cornea do?
Light passes through It bends light
What does the Ciliary muscle do?
Change shape of lens
What does the Retina do?
Contains the light receptor cells (rods and cones)
Detects light and converts it into an electrical impulse
When a object is near is the lens fat or thin?
FATy
What are three differences between the rods and cones?
- rods work in dim light while cones work in bright light
- rods see black and white while cones see color
- rods are for blurry images while cones are for clear images
What controls the shape of the lens?
Ciliary muscles make the lens fatter to
focus light from near objects and
thinner to focus light from distant
objects
How does the lens change when focusing on object at different distances.
When focusing on a near object- the lens
becomes thicker which allows the light
rays to refract (bend) more strongly.
When focusing on a distant object- the
lens is pulled thin which allows the
light rays to refract slightly.
What are the two lenses called and there function?
Diverging lens - correcting short-sightedness
Converging lens - correcting long-sightedness
What is cataracts? how to you corrects it?
cataracts is caused when a protein builds up inside the lens and makes it cloudy
it can be corrected by surgically replacing the with a plastic one to restore full vision
Can you correct colour blindness?
Colour-blindness is genetic and cannot
be corrected
How does laser surgery correct short and long sightedness?
during laser surgery the cornea is reshape
