Lesson 10: Nervous System: Vision II and Dissection Lab
Grade/Subject: High School Biology
Purpose of Lesson: Students will learn the accessory structures of the eye, and conclude study of the eye
with a hands-on laboratory dissecting sheep eyeball.
Objectives: After completing this lesson, students will be able to:
o describe the functions of the accessory structures of the eye
o identify major structures of the mammalian eye from a real eye
o compare the structures of the sheep eye with those of the human eye
Connected to Illinois Standards:
o 11.A.5e Report, display and defend the results of investigations to audiences that may include
professionals and technical experts
o 12.A.5a Explain changes within cells and organisms in response to stimuli and changing
environmental conditions.
Materials: Sheep eyes. Dissecting pans and tools. Gloves. Sheep eye diagram. Student eyeball drawings.
Instructional Sequence:
Introduction/Anticipatory Set: Sheep eyes
Essential questions:
 What does a real mammalian eye look like? We will find out in today’s lab!
 How are sheep and human eyes similar and different?
Link to today’s work:. Today’s dissection will bring our discussion of the eye to a meaningful
close with a hands-on dissection lab.
Detailed Instructional Procedures:
1. Lecture:
 Conjunctiva, eyebrows, eyelashes, lacrimal apparatus: Do humans really need these accessory
structures? What happens if you shave your eyebrows? Can you “cry” tears through your
nose? What are the different causes of conjunctivitis (Pink Eye)?
2. Lab: The sheep eye is a good model for studiying the human eye since the two animals belong to
the same order of mammals. Use your eyeball drawing and diagrams from the book as guides to
identify the sheep structures in the diagrams. Fill in the parts in the diagrams. Time will be
reserved at the end of the lab for teams to share the products from their dissections. This will not
only promote team spirit, but should also prevent “playing” with the eye if students know that
their peers will be looking at the result. Work collaboratively in groups of 3-4. Take turns teasing
the eye tissues apart and isolating the parts.
Closure: Teams share their findings. How difficult was it to identify the parts? What were some problems
encountered in the procedure? What differences are there between sheep and human eyes? Collect
diagram.as lab report. Next lesson we will have a professional optometrist share her expertiseas an eye
health worker
Assessment: Walk among the groups to ensure they are on-task and answer questions Use questions as
diagnostic assessment to ensure comprehension of today’s lesson and connection with previous lessons.
EDN346/Peter Chen
Page 1 of 2
Sheep Eye Structures
(source: http://www.bio.psu.edu/faculty/strauss/anatomy/nerv/dissectedeye.htm)
.
EDN346/Peter Chen
Page 2 of 2