The Eye

Question 1

Draw a diagram of the eye

Answer 1

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Question 2

Name the parts of the eye

Answer 2

Sciera, Choroid, Retina, Fovea, Optic nerve, Blind spot, Arteries and veins, Vitreous humour, External muscle, Conjuntiva, Cornea, Aqueous humour, Pupil, Lens, Iris, Ciliary muscle, Suspensory ligaments

Question 3

What is the function of the eyelid?

Answer 3

Eyelids can cover and protect the eyes.

Question 4

What is the function of the conjunctiva?

Answer 4

A thin transparent lining protecting the cornea.

Question 5

What is the function of the cornea?

Answer 5

Front transparent part of the sclera. It focuses light rays on the retina.

Question 6

What is the function of the sclera?

Answer 6

A tough fibrous outer layer - the “white” of the eye; it maintains the shape of the eyeball.

Question 7

What is the function of the choroid?

Answer 7

The choroid contains blood vessels supplying food and oxygen to the cells of the eye.

Question 8

What is the function of the retina?

Answer 8

The innermost layer that contains the receptor cells [rods and cones].

Question 9

What is the function of the fovea?

Answer 9

The fovea is where our best vision is [mainly cones]

Question 10

Where is the iris?

Answer 10

The front region of the choroid is specialised into the iris

Question 11

What is the function of the iris?

Answer 11

The iris contains blood vessels and melanin [giving us out eye colour], and controls the amount of light entering the eye [through the pupil].

Question 12

What happens to the pupil in bright light?

Answer 12

Pupil constricts

Question 13

What happens to the pupil in dim light?

Answer 13

Pupil dilates

Question 14

What is the function of the ciliary [muscle]?

Answer 14

Thickened edge of the choroid that controls the shape of the lens.

Question 15

What is the function of the suspensory ligaments?

Answer 15

Holds the lens in place.

Question 16

What is the function of the lens?

Answer 16

Like a magnifying glass, it focuses the light rays on the retina.

Question 17

What is the function of the lens?

Answer 17

The lens focuses the light rays on the retina

Question 18

What is accomodation?

Answer 18

Accommodation is the ability of the lens to change its shape (focal length) to form a clear image.

Question 19

Draw a diagram of forming an image on the retina?

Answer 19

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Question 20

How does the eye see distant objects?

Answer 20

For distant objects the ciliary muscle relaxes and so the suspensory ligaments pull tight, pulling the lens thinner - the light doesn’t bend as much

Question 21

How does the eye see close objects?

Answer 21

For close objects the ciliary muscle contracts allowing the lens to go fat, thus bending the light more.

Question 22

What is the function of the aqueous humour?

Answer 22

Watery liquid that supplies the lens and cornea with nutrients and helps keep the shape of the cornea and lens.

Question 23

What is the function of the vitreous humour?

Answer 23

A gel that helps maintain the shape of the eye.

Question 24

What happens when light rays focus on the retina?

Answer 24

Receptor cells are stimulated and impulses are carried along the optic nerve to the brain.

Question 25

What is the function of the blind spot?

Answer 25

Where the optic nerve fibres pass through the retina and there is no room for receptors.

Question 26

Name an eye defect

Answer 26

Long-sighted/short sighted

Question 27

What does long-sighted mean?

Answer 27

You are long-sighted if you can clearly see objects a long way off, but you cannot see things close by.

Question 28

What glasses can correct long-sightedness?

Answer 28

Reading glasses [convex lenses] can correct the problem.

Question 29

Draw a diagram of long sight (and its correction)

Answer 29

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Question 30

What does short-sighted mean?

Answer 30

You are short-sighted if you can clearly see objects close to you, but you cannot see things in the distance.

Question 31

What glasses can correct short-sightedness?

Answer 31

Glasses with concave lenses can correct the problem

Question 32

Draw a diagram of short-sighted (and it’s correction)

Answer 32

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