Eye

Question 1

What is the Cornea?

Answer 1

A curved transparent disc at the front of the eye. Does most of the focusing

Question 2

What is the pupil?

Answer 2

A circular opening whose size is controlled by the iris

Question 3

What is the iris?

Answer 3

A ring of muscles with a hole in the middle (pupil). The iris controls how much light enters the eye

Question 4

What is the lens?

Answer 4

This is soft, flexible and transparent. Its shape can be changed to fine tune the focusing of light onto the retina

Question 5

What is the ciliary muscles?

Answer 5

A ring of muscles at the edge of the eye which circles the lens. When is contracts the lens gets fatter. When it releases the lens gets thinner

Question 6

What is the suspensory ligaments

Answer 6

Strong fibres which attach the lens to the ciliary muscles

Question 7

What is the retina?

Answer 7

Contains the light sensitive cells called rods and cones

Question 8

What is the optic nerve?

Answer 8

Consists of many neurones which carry impulses from the retina to the brain

Question 9

What is the fovea

Answer 9

The region of the retina with the greatest number of cones

Question 10

What is the conjunctiva?

Answer 10

A mucous membrane that covers the eye to prevent infection

Question 11

What happens in dim light?

Answer 11

• The radial muscles contract and circular muscles relax
• The pupil dialates

Question 12

What happens in bright light?

Answer 12

• The radial muscles relax and circular muscles contract
• The pupil constricts

Question 13

What happens when focusing on an object far away?

Answer 13

• Ciliary muscles relax
• Suspensory ligaments are pulled tight
• Lens becomes thin and less convex
  Therefore less light refraction

Question 14

What happens when focusing of an object close up?

Answer 14

• Ciliary muscles contract
• Suspensory ligaments become slack
• Lens becomes thicker and more convex
  Therefore more light refraction