Discuss as appropriate.įor younger students, you could do a teacher led dissection with exploration as the focus. Provide students with the Cow Eye Dissection Lab, and allow them time to answer the questions. ![]() You can save the scalpels and scissors for reuse, but they have to be sterilized and dried with care because they rust easily. The back walls of our eyes are black to absorb light.Īssist students in cleaning up their materials. It is a reflective layer on the back of the eye that causes animal’s eyes to appear as though they are glowing. If it’s too small or becomes damaged, the signals cannot get where they need to go. It is like a cable that carries information from your eye to the brain. Find the optic nerve on the back of the eye. Sometimes this can happen with retinal reattachment surgery. If you look through a flat piece, you can see through it, but once it gets crinkled, it’s hard to make out the images on the other side. If you get folds, wrinkles, or scar tissue on the retina, your vision will be distorted. The vitreous pushes the retina back and makes it lay flat on the back wall of the eye. The retina connects in one spot on the back wall of the eye, and this is known as your “blind spot” if you have vision because light cannot hit this point on the back of your eye. Explain that it is made up of cone cells that give us central vision and help us see color (Cone = Color + Central vision + Clarity – “the 4Cs”) It is also made up of rod cells that help detect whether or not light is present. Flip the eye inside out, and notice the retina hanging from the back of the eye. Remove the remaining vitreous humor from the eye. If you can, look through the lens and discuss what you see. It is soft on the outside but hard on the inside, and it grows new layers each year. The vitreous is made up of protein and water.Įxplain that the lens focuses the light in your eyes. This is the vitreous humor, and it is clear so that light can pass through it. ![]() Explain that it has a jelly-like substance that surrounds it. Remove the hard lens from the rest of the eye. The pupil is in the center and although it appears black when you look in the mirror, it is simply a hole in the middle of the iris. Explain that the iris is the color ring in our eye and is a muscle that can contract and expand to let in more or less light as needed to see. Use the scissors to cut all the way around and remove the cornea. Using the scalpel, make a slit in the sclera on the side of the eye. Locate the sclera, another protective layer. “The liquid that comes out is the aqueous humor which gives nutrients to the eye. Instruct that “The cornea protects the eye like a windshield.” Using the scalpel, help students to slit the cornea. Locate the cornea on the front of the eye. Using their scissors, help students remove it, informing the students that “fat cushions the eye.” Locate the fat and muscle around the eye. I typically require aprons and goggles, but allow gloves and masks to be optional. Gather materials and put on gloves, aprons, goggles, and masks. Protective lab gear such as goggles, aprons, and glovesĬutting utensils and a tray are included in the kit, however, you can order the specimen on its own if your school has scalpels and scissors on hand for you to use. We have typically order several at a time from here: It offers good explanations in age appropriate language.ġ fresh or preserved cow eye specimen. It can be a support for guiding instruction. To get started, watch the YouTube video Cow’s Eye Dissection: Exploratorium. It allows them to participate in a dissection, while teaching the anatomy and structure of the eye. ![]() ![]() This is a great activity for middle and high school students.
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