The eye

The human eye can make clear images of objects.

Figure 4 shows how the human eye focuses light rays from a distant object onto the retina.

Label structures A and B on Figure 4.

Choose answers from the box.

The eye in Figure 4 is focused on a distant object.

Complete the sentence.

Choose the answer from the box.

To focus on a near object the ciliary muscles.

Complete the sentence.

Choose the answer from the box.

To focus on a near object structure B in Figure 4

The eye in Figure 4 is looking at an object in dim light.

Complete the sentence.

Choose the answer from the box.

When the eye looks at an object in bright light the pupil gets smaller.

The size of the pupil is controlled by the.

The retina is sensitive to light.

How does information from the retina reach the brain via structure A in Figure 4 ?

Figure 5 shows the eye of a person who is short sighted looking at a distant object.

The person cannot see the object clearly.

Give the reason why the person cannot see the object clearly.

Short sightedness can be corrected using spectacle lenses.

Give one other way short sightedness can be corrected.

Do not refer to spectacles in your answer.

A person’s eyes can focus on objects at different distances.

A person looks at a distant object.

The person then looks at a near object.

The person’s eyes make adjustments so that the near object forms a clear image.

Which term describes the adjustment of focus from the distant object to the near object?

Tick (✓) one box.

Figure 14 shows the eye.

Which structure in Figure 14 is where the image is focused?

Tick (✓) one box.

Which structure in Figure 14 is a muscle that contracts when focusing on a near object?

Tick (✓) one box.

What happens to the shape of the lens when focusing on a near object?

The eyes can function in dimly-lit areas and in brightly-lit areas.

The iris contains muscles.

Describe how muscles in the iris help the person to see clearly when moving from a dimly-lit area to a brightly-lit area.

It is important to be able to react quickly.

Many people think that drinking coffee decreases reaction time.

Plan an investigation to test the effect of drinking coffee on reaction time.

You should include:

• the test for reaction time that you would use

• how to make the investigation valid.

A person’s eyes can focus on objects at different distances. A person looks at a distant object. The person then looks at a near object. The person’s eyes make adjustments so that the near object forms a clear image.

Which term describes the adjustment of focus from the distant object to the near object? Tick (✓) one box.

Figure 3 shows the eye.

Which structure in Figure 3 is where the image is focused? Tick (✓) one box.

Which structure in Figure 3 is a muscle that contracts when focusing on a near object? Tick (✓) one box.

What happens to the shape of the lens when focusing on a near object?

The eyes can function in dimly-lit areas and in brightly-lit areas. The iris contains muscles. Describe how muscles in the iris help the person to see clearly when moving from a dimly-lit area to a brightly-lit area.

It is important to be able to react quickly. Many people think that drinking coffee decreases reaction time. Plan an investigation to test the effect of drinking coffee on reaction time. You should include:

• the test for reaction time that you would use

• how to make the investigation valid.

The human eye can form images of objects that are at different distances away from the eye. Figure 7 is a diagram of the eye.

Label structures A, B and C on Figure 7.

Choose answers from the box.

The eye in Figure 7 is focused on a distant object.

If the eye then focuses on the words in a book, changes would occur in the eye. The light rays would be refracted more by the lens.

How does the lens refract the light more?

Tick (✓) one box.

Which two structures control the shape of the lens?

Tick (✓) two boxes.

To form a clear image, the light rays entering the eye must focus on one structure in the eye. Name the structure.

An insect flies near a person’s eye. The person blinks. This is a reflex action. Figure 8 shows the coordination system for this reflex action.

Complete Figure 8.

Choose answers from the box below. Write one word in each of boxes 2, 3 and 4 of Figure 8.

Figure 6 shows the brain.

Label A, B and C on Figure 6.

Choose answers from the box.

Which part of the brain controls balance when riding a bicycle?

Tick (✓) one box.

The ears send information about sound to the brain.

Which word describes the brain?

Tick (✓) one box.

What type of cell carries impulses from the ears to the brain?

Human eyes detect light.

Which part of the eye has cells that detect light?

Tick (✓) one box.

The eyes of some birds have specialised cells to detect ultraviolet (UV) light.

Some fruits reflect UV light.

Explain why it is an advantage for birds to be able to detect UV light.

Figure 7 shows a student reading a book.

There are trees on the far side of the field.

The student looks at the trees instead of looking at the book.

What process occurs in the eye when the student looks at the trees instead of looking at the book?

Tick (✓) one box.

What change happens in the student’s eyes when they look up at the trees?

Tick (✓) one box.

The student cannot see the trees in focus.

Name the common defect of the eye which causes distant objects to appear out of focus.

Figure 7 shows the brain.

Which part of the brain becomes more active if a person balances on one leg instead of standing on two legs? Tick (✓) one box.

Name the part of the brain that is responsible for making a decision.

In most MRI scanners the person being scanned needs to stay completely still. A functional MRI (fMRI) scanner allows a person to move while the scanner makes images of the person’s brain activity. Suggest how the fMRI scanner could help to find out more about the brain damage a person has.

Describe how the brain receives information about light entering the eye. You should include the names of structures in your answer.

The eyes of some birds contain cells that detect ultraviolet (UV) light. UV light is reflected by some fruits and the urine of small mammals. Explain how birds that detect UV light have evolved from birds that could not detect UV light.

The human eye can focus on objects at different distances.

Figure 5 shows how a clear image of a distant object is formed in a person’s eye.

Explain how the person’s eye could adjust to form a clear image of a nearer object.

Explain why a long-sighted person has difficulty seeing near objects clearly.

Long-sightedness can be corrected by wearing spectacles.

Describe how spectacle lenses can correct long-sightedness.

Many human actions are reflexes.

Which two of the following are examples of reflex actions?

Tick two boxes.

Figure 12 shows how the size of the pupil of the human eye can change by reflex action.

Name one stimulus that would cause the pupil to change in size from A to B, as shown in Figure 12.

Structure Q causes the change in size of the pupil.

Name structure Q.

Describe how structure Q causes the change in the size of the pupil from A to B.

Figure 13 shows some structures involved in the coordination of a reflex action.

Describe how the structures shown in Figure 13 help to coordinate a reflex action.

Many human actions are reflexes.

Which two of the following are examples of reflex actions?

Tick two boxes.

Figure 1 shows how the size of the pupil of the human eye can change by reflex action.

Name one stimulus that would cause the pupil to change in size from A to B, as shown in Figure 1.

Structure Q causes the change in size of the pupil.

Name structure Q.

Describe how structure Q causes the change in the size of the pupil from A to B.

Figure 2 shows some structures involved in the coordination of a reflex action.

Describe how the structures shown in Figure 2 help to coordinate a reflex action.