Photo credit: https://www.exploratorium.edu
As part of our body systems unit, we have frequently had students perform a cow eye dissection.Exploratorium.edu has a great tutorial that walks through the dissection process step-by-step. I play and pause the video while students follow along. They also provide written instructions. The cow eye dissection is typically introduced when students are learning about the nervous system. We also buy two pig hearts to demonstrate in class. Students get to see a whole heart, and a heart that has been opened up. This ties into the circulatory system.
Before the eye dissection, I had the students “apply and interview” for the jobs that they wanted. The four jobs were: lead surgeon, assistant surgeon, surgical technologist, and recorder. Those that want the job of lead surgeon the most, have their names noted on the whiteboard in front of the class. They each share why they think they would be best for the “job” and they try to convince the class. If there are more positions than volunteers, the class votes for who they want to fill these first positions. Each table group has one lead surgeon. About 9 lead surgeons per class. Next the lead surgeons hear from those who want to be on each team. After all assistant surgeons have had a chance to be interviewed, the lead surgeons and I, select which students will assist in the dissection. Next, we interview the surgical technologists, which collect the tools, and scrub and disinfect the tools afterward. Lastly, the recorder notes the proceedings of the surgery. All students will be provided an opportunity to participate in the surgery, if they wish to. It is primarily a budget constraint that limits us to one eye for every four students, and two hearts for 9-10 classes (the hearts are rotated to each classroom; one whole and one opened up). Students are provided an opportunity to inspect the heart’s chambers if they wish.
Disclaimer: The eyes are purchased, for the classroom from a butcher shop, from cows that have already been slaughtered. These eyes would have otherwise been tossed in the trash. The same is true of the pig hearts.
I have also seen the dissection done with sheep eyes, but cow eyes are much larger and easier to see.
The cow eyes must remain frozen until just prior to use. They do need to be thawed prior to dissection. Keep a tray under the bags of eyes, and the two hearts to catch any fluids, while defrosting the parts.