B3.1 The Eye

Question 1

Cornea

Answer 1

Refracts light into eye

Question 2

Pupil

Answer 2

allows light to enter eye

Question 3

Iris

Answer 3

muscle that alters pupil size, therefore controls amount of light entering eyes

Question 4

Lens

Answer 4

Bioconvex; focuses light onto retina

Question 5

Ciliary muslce

Answer 5

alters size of lens
contracts = fatten
relaxes = thin

Question 6

suspensory ligaments

Answer 6

connects ciliary muscle to the lens

Question 7

optic nerve

Answer 7

carries nerve impulses from photoreceptors to brain

Question 8

retina

Answer 8

where photoreceptors receive light

Question 9

focus on near objects

Answer 9

ciliary muscles contract

lens get fatter

Question 10

focus on distant objects

Answer 10

ciliary muslces relax

lens get thinner

Question 11

short sightedness

Answer 11

lens is too strong/eyeball’s too long
light meets before retina
concave lens bend light outwards for light to reach retina

Question 12

long sightedness

Answer 12

lens is too weak/eyeball’s too short
light does meet at all
convex lens bends light inwards so it meets at retina

Question 13

2 types of photoreceptors

Answer 13

rods - responds to light levels (black + white)

cones - responds to R/G/B light