Anatomy of the eye

Eye Structure

and How we see

The eye works like a camera: Light enters, is focused on a surface, and a picture is made.

Light enters your eye through a clear portion of
the sclera (the tough, white, outer covering of the eye), called the cornea.

Multiple Choice

The white portion of the eye (In Humans).

• Pupil

• Sclera

• Dyslexia

• Retina

The iris is a muscle that controls the size of the
pupil. The iris is the colored part of the eye.

Multiple Choice

The pupil is located at the center of the

• sclera

• iris

• retina

• nothing

Multiple Choice

The opening of the eye where light enters

• Retina

• Sclera

• Pupil

• cornea

Multiple Choice

What part of the eye is this?

• iris

• lens

• cornea

• retina

Multiple Choice

What part of the eye is this?

• cornea

• lens

• iris

• cilicary body

Multiple Choice

Explain why the pupil contracts (becomes smaller).

• To restrict the amount of light entering the eye

• To allow more light into the eye

• To focus light onto the retina

• To stop waste entering the eye

Multiple Choice

What is the purpose of the pupil?

• It regulates the amount of light that enters the eye

• it serves as the center of vision

• it gives the center of the eye its color

• to protect the eye

Multiple Choice

What part of the eye makes the pupil larger and smaller?

• Retina

• Iris

• Lens

• Cornea

Multiple Choice

The thick, gelatinous fluid that fills most of the eyeball is called...

• Aqueous humor

• tapectum lucidum

• vitreous humor

• conjunctiva

Multiple Choice

Why do pupils look black?

• because they are just a hole in the eyeball

• light passes through it and doesn't reflect at all

Multiple Choice

What gives the eye its color?

• cornea

• optic nerve

• pupil

• iris

Multiple Choice

After light passes through the cornea it then passes through the

• Cornea

• Lens

• Vitreous humor

• Pupil

The cornea is curved, so it slightly bends the light
as it goes through.

Light then passes through the aqueous humor (a
clear fluid for eye nourishment) and through the pupil.

The pupil is simply a hole in the iris.

Multiple Choice

When does the pupil dilate (expand)?

• When there is bright light such as on a sunny day

• When there is dim light such as in a dark room

Multiple Choice

The purpose of this part of the eye is to keep the eye from drying out and free of irritants.

• rods

• conjunctiva

• iris

• sclera

The iris is a muscle that controls the size of the
pupil. The iris is the colored part of the eye.

• In bright light, iris expands and pupil gets smaller
• In low light, iris contracts and pupil gets bigger

Multiple Choice

What gives the eye its color?

• cornea

• optic nerve

• pupil

• iris

Directly behind the iris is the lens. This structure
changes shape to focus the light so that we can
see clearly. Its shape is convex, meaning it curves
outward on both sides.

The ciliary muscles above and below the lens
control the shape of the lens.

Multiple Choice

The optic nerve is located in what part of the eye?

• in the front

• right behind the lens

• at the back

• underneath the iris

Multiple Choice

What part of the eye is this?

• choroid 

• sclera 

• cornea

• retina

Behind the lens is a clear gel called the vitreous
humor. After moving through the vitreous humor,
the light strikes the retina. The retina is the lining
on the inside of the back of the eye that contains
two types of light-sensitive cells: rods and cones.

Multiple Choice

What provides nutrients and oxygen to the eye and remove waste?

• Cornea

• Aqueous humour

• Pupil

• Lens

Multiple Choice

This part of the eye focuses light onto the retina.

• Retina

• Optic Nerve

• Lens

• ciliary body

Multiple Choice

What part of the eye makes the pupil larger and smaller?

• Retina

• Iris

• Lens

• Cornea

Rods sense black and white and work in low light.

• L-cones sense long wavelengths in the red range
• M-cones sense mid-range wavelengths in green range
• S-cones sense short wavelengths in the blue range

Cones sense
color and must
have more light
than rods to
work. Three
kinds of cones:

The rods and cones send messages to the brain
through the optic nerve. The brain makes sense of
all the information it is receives.

In your brain, the sight
center is in the back,
between your ears. This
location explains why a
blow to the back of your
head might cause
blindness, even though
your eyes are fine.

Multiple Choice

Cones are light sensitive cells in the retina that

• give you color vision in bright light

• respond in dim light

• give you color vision in dim light

• respond in bright light

Like the pinhole viewer, images that appear on
your retina are upside down and backward. Your
brain interprets them in the right way.

I

The rods and cones send messages to the brain
through the optic nerve. The brain makes sense of
all the information it is receives.

Multiple Choice

The bundle of neural fibers that travel from the retina to the brain is called

• conjunctiva

• rods

• cones

• optic nerve

Multiple Choice

What is the purpose of the pupil?

• It regulates the amount of light that enters the eye

• it serves as the center of vision

• it gives the center of the eye its color

• to protect the eye

Multiple Choice

The eye has a blind spot. Why?

• Because each eye is is damaged in some way

• We all watch too much Netflix and it damages a part of our eye

• The optic nerve connects to the retina and there are no photoreceptors there

• The lens doesn't reflect light onto certain points of the retina

Eye Anatomy Review

• cornea

• pupil

• iris

• anterior chamber

• aqueous humor

• lens

• vitreous humor

• retina

• fovea

• choroid

• sclera

• optic nerve

Multiple Choice

The lens is most like what?

• a kidney bean

• a green pea

• a marble

• a small pebble

Wikipedia http://en.wikipedia.org/wiki/File:Schematic_diagram_of_the_human_eye_en.svg

2004 Microsoft Corporation, One Microsoft Way,
Redmond, WA 98052-6399 USA.

National Cancer Institute at the National Institutes of Health
http://www.cancer.gov/cancertopics/pdq/treatment/retinoblastoma/patient/page1/AllPages/Print

Image Sources

National Eye Institute, National Institutes of Health
http://www.nei.nih.gov/healthyeyes/eyeexam.asp

MedLine Plus, National Institutes of Health
http://www.nlm.nih.gov/medlineplus/ency/presentations/100206_1.htm

MedLine Plus, National Institutes of Health
http://www.nlm.nih.gov/medlineplus/ency/imagepages/9482.htm

Federal Aviation Administration
http://www.hf.faa.gov/webtraining/VisualDisplays/HumanVisSys2.htm

Federal Aviation Administration
http://www.hf.faa.gov/webtraining/visualdisplays/HumanVisSys6.htm

Glaucoma, MedLine Plus, National Institutes of Health
http://www.nlm.nih.gov/medlineplus/ency/imagepages/9349.htm