The eye

Question 1

Sclera fuction?

Answer 1

1. The tough, supporting wall of the eye.

Question 2

Cornea function?

Answer 2

1. The transparent outer layer found at the front of the eye.
2. It refracts light into the eye.

Question 3

Iris function?

Answer 3

1. Contains muscles that allow it to control the diameter of the pupil, and therefore how much light enters the eye.

Question 4

Lens function?

Answer 4

1. The lens focuses the light onto the retina (which contains receptor cells sensitive to light intensity and colour)

Question 5

Optic nerve function?

Answer 5

1. Carries impulses from the receptors on the retina to the brain

Question 6

How does the iris reflex work?

Answer 6

1. When light receptors in the eyes detect very bright light, a reflex is triggered to make the pupil smaller.
2. The circular muscles in the iris contract, and the radial muscles relax.
3. This reduces the amount of light that can enter the eye.

Question 7

Focusing on near objects reflex?

Answer 7

1. Ciliary muscles contract, which slackens suspensory ligaments.
2. Lens become fat.
3. This increases the amount by which it reflects light.

Question 8

Looking at far objects?

Answer 8

1. Ciliary muscles relax, which allows the suspensory ligaments to pull tight.
2. This makes the lens go thin.
3. So it refracts light by a smaller amount.