F2 - SEM2 - Sensng the Environment - 10.2 Sight

Question 1

What is the function of eyebrows?

10.2 Sight

Answer 1

prevents sweat from running into the eye

10.2 Sight

Question 2

What is the function of eyelashes?

10.2 Sight

Answer 2

trap small objects and prevent them from entering the eye

10.2 Sight

Question 3

What is the function of eyelid?

10.2 Sight

Answer 3

closed to protect the eye from dirt and strong light

10.2 Sight

Question 4

Label the diagram

10.2 Sight

Answer 4

1. eyebrow
2. eyelid
3. eyelash
4. eyeball
5. skull
6. orbit
7. eye muscles
8. optic nerve

10.2 Sight

Question 5

What is the function of eye muscles?

10.2 Sight

Answer 5

enable eyeball to rotate in different directions

10.2 Sight

Question 6

Fill in the blank

The eyeball is attached to the skull by ________

10.2 Sight

Answer 6

3 pairs of eye muscles

10.2 Sight

Question 7

The eyeball is held in a socket of the skull called ________

10.2 Sight

Answer 7

The orbit

10.2 Sight

Question 8

Label the diagram

10.2 Sight

Answer 8

1. Cornea
2. Iris
3. Pupil
4. Lens
5. Jelly-like fluid
6. Sclera
7. Retina
8. Blind spot
9. Optic nerve

10.2 Sight

Question 9

What is the function of Cornea?

10.2 Sight

Answer 9

allow light to enter the eye
curved surface help focus light onto the retina

10.2 Sight

Question 10

What is the function of Iris?

10.2 Sight

Answer 10

control the size of the pupil

10.2 Sight

Question 11

What is the function of pupil?

10.2 Sight

Answer 11

an opening at the centre of the Iris
allow light to enter the eye

10.2 Sight

Question 12

What is the function of lens?

10.2 Sight

Answer 12

focus the light onto the retina

10.2 Sight

Question 13

What is the function of jelly-like fluid?

10.2 Sight

Answer 13

maintain the shape of the eyeball

10.2 Sight

Question 14

What is the function of sclera?

10.2 Sight

Answer 14

it is a tough white coat
protect the eyeball

10.2 Sight

Question 15

What is the function of retina?

10.2 Sight

Answer 15

contain light-sensitive cells (specialized sensory cells that detect light)

10.2 Sight

Question 16

What is the function of blind spot?

10.2 Sight

Answer 16

it is a point on the retina where the optic nerve leaves the eye
does not have light-sensitive cells

10.2 Sight

Question 17

What is the function of optic nerve?

10.2 Sight

Answer 17

messages from light-sensitive cells are sent along it to the brain

10.2 Sight

Question 18

Explain the process of how we see

10.2 Sight

Answer 18

1. light from an object enters the eye
2. cornea and the lens bend the light and focus it onto the retina. inverted image is formed on the retina.
3. light-sensitive cells on the retina are stimulated by the light. They send messages to the brain along the optic nerve
4. brain interprets the messages as an upright image of the object

10.2 Sight

Question 19

What is our limitations of eyesight

Answer 19

We cannot see when an object is too near or too afar away

Question 20

T or F
We cannot see an object when its image is formed on the blind spot

Answer 20

True

Question 21

T or F
No images can be formed on the blind spot

Answer 21

False

Question 22

How is colour blindness caused

Answer 22

It is inherited

Question 23

What is the effect of astigmatism

Answer 23

They have blurred vision

Question 24

How to test for astigmatism

Answer 24

Use one eye to look

Question 25

What is the effect of cataract

Answer 25

Lens become cloudy

Question 26

Spell the sickness with blurred vision

Answer 26

Astigmatism

Question 27

How does the lens focus light to retina?

Answer 27

Lens is elastic
Change the thickness to focus light
Nearer object - thicker lens
Further object - thinner lens

Question 28

Name the 2 types of light sensitive cells on the retina and their functions

Answer 28

Rod cells
Black and white vision only
Sensitive to dim light

Cone cells
Colour vision
Sensitive to bright light
3 types of come cell - each sensitive to a colour, red, green and blue

Question 29

Name 2 tools that extend our vision to see small objects

Answer 29

Hand lenses and microscope

Question 30

Name 2 tools to extend our vision to see faraway objects

Answer 30

Binoculars and telescope

Question 31

What are the common eye defects?

Answer 31

Short sight, long sight

Question 32

Beside short sight and long sight, what are the other defects or disease?

Answer 32

Colour blindness (defect)
Astigmatism (defect)
Cataract (disease)

Question 33

What is the symptom, causes of short sight? How to correct?

Answer 33

Symptom - cannot see distant object clearly
Causes - thick lens or long eyeball (image is formed in front of retina)
Correct - wear concave lens to correct

Question 34

What is the symptom, causes of long sight? How to correct?

Answer 34

Symptom - cannot see near object clearly
Causes - thin lens or short eyeball (image is formed behind retina)
Correct - wear convex lens to correct

Question 35

What is the symptoms of colour blindness? How to correct?

Answer 35

Symptom - not distinguish some or all colour, common is red-green colour blindness
Cause - inherit defect
Correct - no

Question 36

What is the symptom, causes of Astigmatism?

Answer 36

Symptom - blurred vision, more blurry when looking at the centre of the chart with one eye
Cause - cornea and/or lens being unevenly curved

Question 37

What is the symptom, causes of cataract?

Answer 37

Symptom - blurred vision
Cause - lens become cloudy

Question 38

T or F
Cataract is a eye defect

Answer 38

False
Cataract is a eye disease

Question 39

5 Ways of eye care

Answer 39

Sufficient lights and keep distance when reading
Give eyes a rest by looking at distant object every 30 minutes
Wear sunglasses when you are in bright sunlight
Have regular eye check
Don’t rub your eye (cause infection)