The Eye

Question 1

What is the eye?

Answer 1

• hollow ball filled with fluid
• allows us to see by focusing light on photoreceptors at the back

Question 2

What are the layers of the eye?

Answer 2

• external: sclera and cornea
• intermediate: choroid, iris, pupil, ciliary muscles
• internal: retina

Question 3

Describe the sclera

Answer 3

Tough, white outer covering of eye

Question 4

Describe the cornea

Answer 4

Transparent area of sclera at front of eye (light enters here)

Question 5

Describe the choroid

Answer 5

• intermediate layer
• absorbs stray light waves
• contains blood vessels that supply eye with nutrients and oxygen

Question 6

Describe the iris

Answer 6

Made of muscle that contracts or relaxes to allow different amounts of light in (adaptation)

Question 7

Describe the pupil

Answer 7

The “hole” in the centre of the eye where light gets through

Question 8

Describe the coliseum muscle/lens

Answer 8

Ciliary muscle adjusts lens to help focus light on retina

Question 9

Describe the retina

Answer 9

• internal layer of the eye
• contains photoreceptors:
  
  • rods: sensitive to light intensity (brightness)
  • cones: sensitive to different colors (concentrated in fovea centralis)
  • optic nerve: collects this information and sends it to the brain

Question 10

Describe the aqueous humour

Answer 10

• fluid in anterior (front) chamber of eye
• maintains cornea shape
• provides oxygen and nutrients to lens and cornea

Question 11

Describe the vitreous humour

Answer 11

• fluid in posterior (rear) chamber
• helps maintain shape of eyeball