Concept Practice
Structures of the Eye

Chapter 1. Structures of the Eye

blind spot
point at which the optic nerve leaves the eye
lens
structure inside the eye that changes shape to focus images on the retina
cones
photoreceptor cells in the eye specialized for detailed color vision in bright light
optic nerve
carries neural impulses from the eye’s retina toward the brain
cornea
clear outer surface of the eyeball
pupil
adjustable opening that allows light to enter the eye
fovea
center of clear vision, around which the cones cluster
retina
light-sensitive inner surface of the eye, containing rods and cones
iris
ring of muscle in the eye that controls the size of the pupil
rods
photoreceptor cells in the eye specialized for monochrome vision in dim light
Structures of the Eye
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Bright blue eye close up
Learning Objectives:

Locate the major structures of the eye.

Identify the basic function of each part of the eye.

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Review

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Diagram of eye.  The structures of the eye are labeled from front to back of the eye.  The cornea is highlighted at the front of the eye.

1. Light enters the eye through the cornea, which protects the eye and helps focus the light.

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Diagram of eye.The structures of the eye are labeled from front to back of the eye.  The iris and pupil, which are located directly behind the cornea, is highlighted near the front of the eye.

2. Light then passes through the pupil, a small adjustable opening regulated by the iris, a colored muscle surrounding the pupil.

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Diagram of eye.   The structures of the eye are labeled from front to back of the eye.  The lens is highlighted at the front of the eye, behind the pupil.  Also, the retina is highighted and refers to the inner lining of the eye ball.

3. Behind the pupil is a lens that changes shape to focus the incoming light rays and help form an image on the retina, the eyeball’s inner surface containing light-sensitive photoreceptor cells called rods and cones.

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Diagram of eye. The structures of the eye are labeled from front to back of the eye.  The fovea is highlighted in the center of the retina at the back of the eye, directly behind the lens.

4. The central point of focus on the retina is called the fovea; the cones are clustered around the fovea, while the rods are mainly in the peripheral retina.

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Diagram of eye.   The structures of the eye are labeled from front to back of the eye.  The optic nerve is highlighted as it exits the back of the eye, underneath the fovea. The spot where the optive nerve leaves the eye is where the blind spot is located.

5. The retinal cells send their messages to the brain through the optic nerve. Where the optic nerve leaves the eye, there are no photoreceptors. This creates a blind spot.

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Practice: Exploring the Eye

Roll over each structure to see a brief description of the function of that part of the eye.

Function of the selected part of eye:

clear outer surface of the eyeball

ring of muscle that controls the size of the pupil

changes shape to focus images on the retina

light-sensitive inner surface of the eye, containing rods and cones

center of clear vision, around which the cones cluster

carries neural impulses from the retina toward the brain

point at which the optic nerve leaves the eye

adjustable opening that allows light to enter the eye

 Diagram of eye.  The following structures of the eye are labeled from front to back of the eye: cornea, iris, pupil, lens, retina, fovea, blind spot, optic nerve
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Quiz 1

Drag each label to the line pointing to the appropriate structure. When all the labels have been placed, select the CHECK ANSWER button.

Diagram of eye with labels removed
Select the NEXT button and move to Quiz 2.
Perhaps you should go back to review the locations of each of these parts of the eye.
Blind spot
Fovea
Retina
Cornea
Lens
Pupil
Iris
Optic nerve
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Quiz 2

Match the eye structures with their functions by dragging each colored circle to the appropriate gray circle. When all the circles have been placed, select the CHECK ANSWER button.

Select the NEXT button and move to the Conclusion.
Perhaps you should go back to review the functions of each of these parts of the eye.
retina
iris
optic nerve
blind spot
pupil
cornea
fovea
lens
clear outer surface of the eyeball
adjustable opening that allows light to enter the eye
ring of muscle that controls the size of the pupil
changes shape to focus images on the retina
light-sensitive inner surface of the eye, containing the rods and cones
center of clear vision, around which the cones cluster
point at which the optic nerve leaves the eye
carries neural impulses from the retina toward the brain
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Bright blue eye close up
Congratulations!
You have completed the activity Structures of the Eye.