10.2 Sight

Question 1

3 main parts of eye

Answer 1

Eyebrow, eyelid, eyelash

Question 2

Eyebrow function

Answer 2

X sweat

Question 3

Eyelid function

Answer 3

Close: dirt, strong light
Blink: moisten surface

Question 4

Eyelash function

Answer 4

X small particles (dust)

Question 5

80% of the eye is hidden in the _____

Answer 5

Socket

Question 6

10 parts of eye

Answer 6

Focusing muscle Sclera
Cornea Retina
Iris Blind spot
Pupil Optic nerve
Lens
Jelly-like fluid

Question 7

Focusing muscle function

Answer 7

Lens thickness

Question 8

Cornea function

Answer 8

Light pass, focus light

Question 9

Iris function

Answer 9

Pupil size

Question 10

Pupil function

Answer 10

Regulate amt of light

Question 11

Lens function

Answer 11

Light pass, focus light

Question 12

Jelly like fluid function

Answer 12

Focus light
Maintain eyeball shape

Question 13

Sclera function

Answer 13

Protect eyebal

Question 14

Retina function

Answer 14

Light sensitive cells detect light, produce signals

Question 15

Blind spot function

Answer 15

Optic nerve leaves
No cells

Question 16

Optic nerve function

Answer 16

Signals brain

Question 17

All 10 parts of eye and functions

Answer 17

Focusing muscle: lens thickness Sclera: protect eyeball
Cornea: light pass, focus light Retina: light sensitive cells detect light, signal
Iris: pupil size Blind spot: optic nerve leaves, no cells
Pupil: regulate amt of light Optic nerve: signals brain
Lens: light pass, focus light
Jelly-like fluid: eyeball shape, focus light

Question 18

When and how does pupil size change to regulate amt of light

Answer 18

Bright: smaller, decrease light
Dim: larger, increase light

Question 19

How are images formed in the eye

Answer 19

1. Light enters
2. Cornea, lens, jelly like fluid focus light onto retina
3. Sharp inverted image on retina; light sensitive cells on retina stimulated by light, produce signals
4. Signals sent to brain through optic nerve; interprets signals as upright image.

Question 20

The lens is ____. It’s thickness can be changed by the _________ surrounding it, so that _______ from objects at different distances can be focused onto the _________.

Answer 20

Elastic, focusing muscles, light, retina

Question 21

What does function of each part of the eye relate to

Answer 21

Its form

Lens is transparent -> light can pass through
Lens is elastic -> thickness can be changed

Question 22

Looking at near objects

Answer 22

Focusing muscle contracts, thicker lens
（縮、厚片）

Question 23

Looking at distant objects

Answer 23

Focusing muscle relaxes, thinner lens
（放鬆、薄片）

Question 24

2 kinds of light sensitive cells on retina

Answer 24

Cone cells, rod cells

Question 25

Cone cells

Answer 25

- bright light sensitive - 3 types (rgb) - detect colour

Question 26

Rod cells

Answer 26

- dim light sensitive - cant detect colour

Question 27

Why difficult to distinguish colours in dim light

Answer 27

Only rod cells are stimulated and send signals to brain They cant detect colour

Question 28

Our eyes have ______. Cant see obj that are too _____, _____ or _____

Answer 28

Limitations, small, close, far

Question 29

We can use ________ to extend our vision

Answer 29

Optical instruments

Question 30

What optical instruments and what they can see

Answer 30

1. Binoculars: birds 2. Hand lens: bee 3. Light microscope: plant cells 4. Electron microscope: viruses 5. Astronomical telescope: mars

Question 31

What’s another limitation, where and why

Answer 31

Blind spot, located on retina No light sensitive cells; when image is formed, no signals are sent to brain, cant see obj

Question 32

Common eye defects

Answer 32

Short sight long sight Astigmatism Cataract Colour blindness

Question 33

Short sight Reason, cause, correction

Answer 33

Image is formed in front of retina Lens too thick / Eyeball too long / both （厚長） Concave

Question 34

Long sight Reason, cause, correction

Answer 34

Image formed behind retina Lens too thin / eyeball too short / both (薄短） Convex

Question 35

Astigmatism Cause, reason , correction

Answer 35

Cornea / lens / both unevenly curved Light can’t be focused on retina Diff curvatures at diff points

Question 36

Cataract Reason, cause, correction

Answer 36

Light cant pass through cloudy lens -> blurred vision Old age, eye injuries, prolonged sunlight exposure, heredity Artificial lens through surgery

Question 37

Colour-blindness Reason, cause, correction

Answer 37

Defect in one or more cone cells, affect distinguish colours Inherited No correction

Question 38

How to protect our eyes

Answer 38

1. Rest, distant obj 2. Sufficient, not strong light; read 30cm 3. Monitor 50-70cm 4. Goggles 5. Regular eye checkups 6. Hat, sunglasses 7. X bend 8. X moving vehicle 9. X rub, infection