Classroom Teacher Preparation
Life Science 7: Eye Dissection
Please use the following to prepare for the next SfS lesson.
Description
After reviewing lab safety, the instructor briefly introduces the dissection procedure and students work in pairs to explore
the anatomy of a preserved sheep eye. We end the lesson with a review of mammalian eye anatomy and the basic
mechanics of vision.
Preparation:
This lesson is a general introduction to the anatomy of the eye and the physiology of vision. Students do not need
background knowledge of the subject matter.
Note: For students not wishing to participate in the dissection, there is a virtual online tour of the eye available
(http://www.exploratorium.edu/learning_studio/cow_eye/index.html). Access to tablets or a computer with Internet access
during class time would allow them to virtually review the material. Please make every attempt to provide a suitable
computer or tablet during our class time.
Vocabulary:
Please introduce these terms before the lesson:
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Inverted - flipped upside-down or upside-down as well as left-to-right
Aperture - a small opening limiting the passage of light
These terms will be defined in lesson:
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Aqueous humor - clear, watery fluid found in the anterior chamber of the eye. Maintains pressure and nourishes
the cornea and lens
Vitreous humor - gel-like substance found inside the eye cavity; provides spherical shape to the eye
Optic nerve – bundle of more than one million axons from cells that carry visual signals from the eye to the brain
Cornea - window to the eye; Provides most of the focusing power when light enters the eye
Iris - Controls the size of the pupil through contraction or expansion of muscles; Melanin, the pigmentation of the
iris, gives the eye color
Pupil - the black circle seen in the eye; a hole that controls the amount of light entering the eye; becomes smaller
in bright environments to allow less to enter the eye; expands in the dark to allow more light in
Lens - transparent tissue that bends light passing through the eye; changes shape to focus light; Located behind
the pupil, it provides fine-tuning for focusing and reading
Retina - Consists of a layer of tissue on the back portion of the eye containing photoreceptor cells responsive to
light (cones and rods) and acts like the film of a camera; converts light to electrical signals that are sent to the
brain via the optic nerve
Sclera - tough, white outer covering of the eyeball; extrinsic eye muscles attach to the sclera and move the eye
Tapetum lucidum - colorful, shiny material located behind the retina; found in animals that have good night vision
and reflects light back through the retina
Room Set Up for Activities:
Students will work with a partner at their desks during the dissection. All materials should be cleared from their work area
before beginning the lesson. Desks should be wiped down with cleaner following the dissection.
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Safety
Gloves are required. We use powder-free latex gloves by default, however a box of one-size-fits all polyethylene gloves
will also be available when latex is in use, and substitute gloves of another material are available for the whole class upon
special request. Please inform the instructor of a latex allergy before the lesson begins.
The dissection procedure requires the use of sharp scissors; therefore, goggles must be worn at all times during this
activity. Hands should be washed immediately following the lesson.
Lesson Objectives – SWBAT (“Students Will Be Able To…”):
4-8
To actively participate in a science discovery activity
To identify the major structures making up the mammalian eye
To understand how light is transmitted into the eye and how messages are sent to the brain
To recognize similarities and differences between a sheep eye and a human eye
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MCAS/NGS Standards Covered:
MCAS Standards:
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PreK–2 LS6 Recognize that people and other animals interact with the environment through their senses of sight,
hearing, touch, smell, and taste.
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LS6 6 -8 Identify the general functions of the major systems of the human body and describe ways that these systems
interact with each other.
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9 -12 LS4.4 Explain how the nervous system mediates communication among different parts of the body and mediates
the body’s interactions with the environment. Identify the basic unit of the nervous system, the neuron, and explain
generally how it works.
NGS Standards:
4-PS4-2. Develop a model to describe that light reflecting from objects and entering the eye allows objects to be seen.
4-LS1-2. Use a model to describe that animals receive different types of information through their senses, process the
information in their brain, and respond to the information in different ways.
MS-LS1-8. Gather and synthesize information that sensory receptors respond to stimuli by sending messages to the brain
for immediate behavior or storage as memories.
Related Modules
Life Science 30: Motor Learning – This module demonstrates the adaptability of the human brain using prism goggles and
beanbags and reveals how connections between neurons in the brain change during the learning process.
Life Science 3: Visual Illusions – In this lesson, students take a detailed look at human vision and discuss visual illusions.
Additional Resources:
WGBH Videos and Activities: The first time you log in to the PBS Learning Media website you will be asked to create an
account and provide an email and password. Once you have logged in, select “keep me logged in” to avoid having to
repeat the process.
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WGBH video: http://mass.pbslearningmedia.org/resource/idptv11.sci.life.stru.living.d4keye/eyes/
Cow Eye Dissection Interactive: http://mass.pbslearningmedia.org/asset/lsps07_int_coweye/
Science from Scientists • 515 Beacon Street • Boston, MA 02215
617-314-7773 • info@sciencefromscientists.org • www.sciencefromscientists.org
Copyright © 2014 Science from Scientists
Page 2