WE DISSECT EYES IN BRAIN AND BEHAVIOR!!! We also dissect
brains, but I’m not sure if there are rules against taking pictures of them,
whereas I’m pretty sure HIPAA doesn’t apply to cows’ eyes, so it seemed safer to
skip the brains and go with the eyes for posting pictures on the Internet. I
also didn’t want to get any of my camera-containing devices dripping in formaldehyde,
since the brains are preserved.
Here’s how to dissect a cow’s eye in five easy steps,
learning team-style:
Warning: This post
is full of potentially graphic pictures.
Disclaimer/anti-warning:
However, they were taken with my silly-phone (i.e., not smartphone), since I
forgot to charge my iPad that day, so they might actually just be too blurry to
see.
Plug for Penn, since
it’s getting to be recruitment time: Every student gets an iPad! We take
notes on them, instead of lugging huge stacks of paper around.
- Three
eyes per learning team magically appear in the first-floor Stemmler lab rooms.
- Find
the optic nerve and the extra-ocular muscles (muscles around the eye that
control eye movement), and cut off the muscles.
- Cut
away the front part of the eye. Now you can see the lens (that round blob in
the middle), and the vitreous humor behind it. The retina, which contains the
photoreceptors that allow us to see, is in the wall around the vitreous humor.
- Play
with the vitreous humor. It’s surprisingly jello-like—on a scale of 1 to 10
where 1 is water and 10 is jello, I’d probably give it a 6.5. If you look
through the vitreous at the lens from the other side, you can see a shape
exactly like the Mercedes-Benz logo on the back of the lens. Nature’s form of product
placement?
- Look
at the rest of the eye, without the vitreous humor. It’s blue in cows, which helps
collect light that isn’t absorbed by the photoreceptors the first time around.
That’s why they can see better in the dark than we can. However, it also means
that their vision is kind of blurry. (Wikipedia has a better picture)
Ta-da! Basically, Brain and Behavior is super cool.
