Chapter 6 eyes 1 Flashcards Preview

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Flashcards in Chapter 6 eyes 1 Deck (17)
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1
Q

What is astigmatism?

A

astigmatism is blurred vision caused by irregularly shaped cornea

2
Q

What is a blind spot?

A

the area where the optic nerve enters the retina is the blind spot where there are no light sensing cells

3
Q

What is the cornea?

A

the cornea is transparent cells that cover the eye.

4
Q

What is the iris?

A

the iris is the colored circle of muscle surrounding the pupil

5
Q

What is the optic nerve?

A

the large nerve that sends signals to the brain from the eye

6
Q

What is the pupil?

A

the opening in the eye to let light through

7
Q

What is the retina?

A

the area at the back of the eye where light focusses

8
Q

What is the sclera?

A

the sclera is the opaque tissue that surrounds the cornea– the white of the eye

9
Q

What does the cornea-lens-retina system do?

A

the cornea-lens-retina system focusses light at the back of the eye

10
Q

What converts light into electric signals?

A

the special cells (rods and cones) in the retina convert to electric signals.

11
Q

Why is light converted to electric signals?

A

the brain can interpret/read the electric signals

12
Q

How does light enter the eye?

A

through the pupil

13
Q

why does the pupil appear dark?

A

the pupil is dark because light passes through it, and is not reflected back.

14
Q

what does the iris do?

A

the iris is a muscle that controls the amount of light entering through the pupil

15
Q

What does the iris do in bright light?

A

the iris contracts (goes smaller) in bright light almost closing the pupil

16
Q

What does the iris do in dim light?

A

the iris dialates (gets bigger) in bright light opening the pupil

17
Q

What is the purpose of the cornea?

A

the cells cover the eye, transparent and let light through, but strong enough to hold the eye together.