The Eye Nervous System

Question 1

Function of cornea.

Answer 1

The transparent lens that refracts light as it enters the eye.

Question 2

Function of iris.

Answer 2

Controls how much light enters the pupil.

Question 3

Function of lens.

Answer 3

The transparent disc that can change shape to focus light onto the retina.

Question 4

Function of the pupil.

Answer 4

The hole that allows light to enter the eye.

Question 5

Function of the retina.

Answer 5

Contains light receptor cells (rods which detect light intensity and cones which detect colour)

Question 6

Function of the optic nerve.

Answer 6

A sensory neurone that carries impulses between the eye and the brain.

Question 7

What happens to the radial muscles when there is dark light/ bright light?

Answer 7

Dark light= contracted

Bright light= relaxed

Question 8

What happens to the circular muscles when in dark light/ bright light?

Answer 8

Dark light= relaxed

Bright light= contracted

Question 9

What happens to the pupil size in dark light/ bright light?

Answer 9

Dark light= wide

Bright light= narrow

Question 10

Definition of accommodation

Answer 10

The process of changing the shape of the lens to focus on near or distant objects

Question 11

What happens to
-ciliary muscles
- suspensory ligaments
-lens
When an object is close by?

Answer 11

• ciliary muscles: contracted
• suspensory ligaments: slack
• lens: fatter

Question 12

What happens to
- ciliary muscles
- suspensory ligaments
- lens
When an object is far away?

Answer 12

• ciliary muscles: relaxed
• suspensory ligaments: pulled tight
• lens: thinner

Question 13

How does refraction of light change when an object is close by/ far away?

Answer 13

Close by: refraction of light increases.

Far away: refraction of light is less.

Question 14

How do the light rays change when an object is close by/ far away?

Answer 14

Close by: light rays are diverging

Far away: light rays are parallel.

Question 15

Definition of myopia (short sightedness)

Answer 15

You can see objects at a short distance away, but struggle to see objects at a distance.

Question 16

Why does myopia occur?

Answer 16

The eyeball is too long for the strength of the lens
The cornea is too sharply curved.
When the eye attempts to produce and image, it falls short of the retina.

Question 17

How can you correct myopia?

Answer 17

Myopia can be corrected by a concave lens which diverges the light rays before they reach/enter the eye.

Question 18

Definition of hyperopia (long sightedness)

Answer 18

You can see objects at long distances away, but struggle to see near objects.

Question 19

When does hyperopia happen?

Answer 19

It happens when the lens is too weak because it is not thick enough.
When the eyeball is too short.
The cornea is not curved enough.
When the eye attempts to produce an image, it falls behind the retina.

Question 20

How can hyperopia be corrected?

Answer 20

It can be corrected by a x lens which converges the light rays before they reach/ enter the eye.