F2 - SEM2 - Sensng the Environment - 10.2 Sight Flashcards
What is the function of eyebrows?
10.2 Sight
prevents sweat from running into the eye
10.2 Sight
What is the function of eyelashes?
10.2 Sight
trap small objects and prevent them from entering the eye
10.2 Sight
What is the function of eyelid?
10.2 Sight
closed to protect the eye from dirt and strong light
10.2 Sight
Label the diagram
10.2 Sight
- eyebrow
- eyelid
- eyelash
- eyeball
- skull
- orbit
- eye muscles
- optic nerve
10.2 Sight
What is the function of eye muscles?
10.2 Sight
enable eyeball to rotate in different directions
10.2 Sight
Fill in the blank
The eyeball is attached to the skull by ________
10.2 Sight
3 pairs of eye muscles
10.2 Sight
The eyeball is held in a socket of the skull called ________
10.2 Sight
The orbit
10.2 Sight
Label the diagram
10.2 Sight
- Cornea
- Iris
- Pupil
- Lens
- Jelly-like fluid
- Sclera
- Retina
- Blind spot
- Optic nerve
10.2 Sight
What is the function of Cornea?
10.2 Sight
allow light to enter the eye
curved surface help focus light onto the retina
10.2 Sight
What is the function of Iris?
10.2 Sight
control the size of the pupil
10.2 Sight
What is the function of pupil?
10.2 Sight
an opening at the centre of the Iris
allow light to enter the eye
10.2 Sight
What is the function of lens?
10.2 Sight
focus the light onto the retina
10.2 Sight
What is the function of jelly-like fluid?
10.2 Sight
maintain the shape of the eyeball
10.2 Sight
What is the function of sclera?
10.2 Sight
it is a tough white coat
protect the eyeball
10.2 Sight
What is the function of retina?
10.2 Sight
contain light-sensitive cells (specialized sensory cells that detect light)
10.2 Sight
What is the function of blind spot?
10.2 Sight
it is a point on the retina where the optic nerve leaves the eye
does not have light-sensitive cells
10.2 Sight
What is the function of optic nerve?
10.2 Sight
messages from light-sensitive cells are sent along it to the brain
10.2 Sight
Explain the process of how we see
10.2 Sight
- light from an object enters the eye
- cornea and the lens bend the light and focus it onto the retina. inverted image is formed on the retina.
- light-sensitive cells on the retina are stimulated by the light. They send messages to the brain along the optic nerve
- brain interprets the messages as an upright image of the object
10.2 Sight
What is our limitations of eyesight
We cannot see when an object is too near or too afar away
T or F
We cannot see an object when its image is formed on the blind spot
True
T or F
No images can be formed on the blind spot
False
How is colour blindness caused
It is inherited
What is the effect of astigmatism
They have blurred vision
How to test for astigmatism
Use one eye to look
What is the effect of cataract
Lens become cloudy
Spell the sickness with blurred vision
Astigmatism
How does the lens focus light to retina?
Lens is elastic
Change the thickness to focus light
Nearer object - thicker lens
Further object - thinner lens
Name the 2 types of light sensitive cells on the retina and their functions
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
Name 2 tools that extend our vision to see small objects
Hand lenses and microscope
Name 2 tools to extend our vision to see faraway objects
Binoculars and telescope
What are the common eye defects?
Short sight, long sight
Beside short sight and long sight, what are the other defects or disease?
Colour blindness (defect)
Astigmatism (defect)
Cataract (disease)
What is the symptom, causes of short sight? How to correct?
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
What is the symptom, causes of long sight? How to correct?
Symptom - cannot see near object clearly
Causes - thin lens or short eyeball (image is formed behind retina)
Correct - wear convex lens to correct
What is the symptoms of colour blindness? How to correct?
Symptom - not distinguish some or all colour, common is red-green colour blindness
Cause - inherit defect
Correct - no
What is the symptom, causes of Astigmatism?
Symptom - blurred vision, more blurry when looking at the centre of the chart with one eye
Cause - cornea and/or lens being unevenly curved
What is the symptom, causes of cataract?
Symptom - blurred vision
Cause - lens become cloudy
T or F
Cataract is a eye defect
False
Cataract is a eye disease
5 Ways of eye care
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)
