the eye

Question 1

identify the main parts of the eye

Answer 1

cornea, lens, iris, retnia, optic nerve

Question 2

explain how they are adapted to their function

Answer 2

Cornea: focuses light onto the RETNIA - is clear, colourless and curved
Iris:Controls how much light enters the pupil( pupil size) -contains muscles
Lens:Further refracts light to focus it onto the retina - clear, colourless, curved can change shape
Retina: detects light waves + produce impulse - contains rod, cone cells and sensory neurone
Optic nerve:Carries impulses between the eye and the brain

Question 3

explain how receptor cells allow full color vision in bright light

Answer 3

cones are receptor cells that are sensitive to color of light, rods are more sensitive in DIM light but CAN’T sense colour CONES are sensitive to different colours but NOT as good in dim lights.
LIGHT is refracted as it passes from air into the cornea because it’s going from a gas/liquid air into a solid medium eye further refraction occurs as light passes through the lens in a normal shaped eyeball the refraction focuses the light perfectly on the retnia and produces a clear image

Question 4

long-sightendness

Answer 4

lens in the wrong shape doesn’t bend the light enough or the eye ball is too short light from near objects are brought into focus behind the retnia

Question 5

how can it be corrected

Answer 5

wearing glasses or contacts with a concave lens

Question 6

near-sightedness

Answer 6

lens wrong shape and bends the light TOO MUCH light from distant objects are brought into focus IN FRONT of the RETNIA

Question 7

colour

Answer 7

red or green cones in the RETNIA are not working properly no cure bc cones cells can’t be replaced

Question 8

contaract

Answer 8

cloudy patch on the lens which stops light from being able to enter the eye - blurred vision, color less vivid, hard seeing in bright light

Question 9

contaracts treatment

Answer 9

replacing faulty lens with an artificial one