12.2 Photoreception

Question 1

External layer of the eye:

Answer 1

Sclera

cornea

Question 2

Intermediate layer of the eye

Answer 2

choroid
iris
pupil
ciliary muscle

Question 3

Internal

Answer 3

retina
rods/cones
optic nerve

Question 4

sclera

Answer 4

white tough fibrous protective layer

Question 5

cornea

Answer 5

where the light enters the eye

transparent part of the sclera at the front of the eye

Question 6

Choroid

Answer 6

Absorbs stray light rays that are not detected by photoreceptors

contains blood vessels that nourish the eye

Question 7

Iris

Answer 7

Allows light to enter by adjusting the size of the pupil

Question 8

pupil

Answer 8

the hole

Question 9

adaptation

Answer 9

The iris adjusting the size of the pupil; based on light conditions

Question 10

retina

Answer 10

thin layer of tissue that contains the photoreceptors rods/cones

Question 11

rods

Answer 11

sensitive to light intensity

more concentrated on the edges

Question 12

cones

Answer 12

sensitive to different colours

most densely found in the fovea centrlalis

Question 13

optic nerve

Answer 13

where the rods and cones send sensory impulses to the brain

Question 14

Aqueos humour

Answer 14

a clear watery fluid that maintains the shape of the cornea and provides oxygen and nutrients for the surrounding cells including those of the lens and cornea

Question 15

vitreous humour

Answer 15

jelly like fluid that helps maintain the shape of the eyeball

Question 16

Accommodation (2)

Answer 16

the ability of the lens to change shape ignorer to focus images clearly on the retina
- a reflex

Question 17

Astigatism

Answer 17

Uneven curvature of part of the cornea. Because the cornea is asymmetrical it cannot bend light rays so that they meet at the correct focal point

Question 18

Myopia

Answer 18

Eyeball enlongated
- focused light falls infront of the retina instead of the photoreceptors

nearsighted

Question 19

Hyperopia

Answer 19

farsighted
eyeball is too short

light falls behind the retina

Question 20

how do photoreceptors relay visual info to the brain?

Answer 20

rods and cones send neurotransmitters that inhibit messages. When stimulated they stop sending neurotransmitter that inhibit and the bipolar cells become depolarize and sends message to ganglion cells which ends form the optic nerve.