THE HUMAN EYE

Question 1

What parts of the eye are responsible for light refraction?

Answer 1

1. Aqueous Humour
2. Cornea (most refraction)
3. Lens
4. Vitreous Humour

Question 2

What happens to the pupil in bright light?

Answer 2

The circular muscle of the iris contract, radial muscle of the iris relax.
The pupil constricts, reducing the amount of light entering the eye.
CCRR

Question 3

What happens to your pupil in dim light?

Answer 3

The radial muscle of the iris contract, the circular muscle of the iris relax.
The pupil dilates, increasing the amount of lights entering the eye.
RCCR

Question 4

What happens when a person tries to focus on a distant object?

Answer 4

1. Ciliary muscles relax, pulling on the suspensory ligament.
2. Suspensory ligaments become taut, pulling on the edge of the lens.
3. Lens become thinner and less convex, pulling on the edge of the lens.
4. Light rays from the distant object are sharply focused on the retina.
5. Photoreceptors are stimulated.
6. Nerve impulses are transmitted by the optic nerve to the brain. The brain interprets the impulse and sees the distant object.

Question 5

What happens when a person tries to focus on a near object?

Answer 5

1. Ciliary muscles contract, relaxing their pull on the suspensory ligament.
2. Suspensory ligaments become slack, relaxing their pull on the edge of the lens.
3. Lens become thicker and more convex, pulling on the edge of the lens.
4. Light rays from the near object are sharply focused on the retina.
5. Photoreceptors are stimulated.
6. Nerve impulses are transmitted by the optic nerve to the brain. The brain interprets the impulse and sees the near object.