Wednesday, March 4, 2020

Homeschool Science: Dissect a Sheep Brain

Here's a photograph of Jones snuggling me on a Sunday:

Stop reading here if you don't want to see photos of my teenager dissecting a sheep brain at our kitchen table.

Chapter 2 of Will's AP Psychology text, Myers' Psychology, is all about the biology of the mind. I'll share more of what both kids did as part of our entire biology of the mind study, but only Will chose to dissect a sheep brain.

For resources, we used this book, which has an appendix covering the dissection of a sheep brain--

--and this video that we watched three times, once the first time Will studied the biology of the mind chapter, once right before the dissection, and once during the dissection, pausing as often as we needed for Will to follow along:

We didn't find this next video nearly as helpful overall, as it goes REALLY fast, but it was helpful to see how to remove the dura mater, as the previous video starts with it already snipped away:

Here's Will attempting to snip through her own sheep's dura mater:

The cerebrum is a little easier to expose--

--but the cerebellum is quite tough to expose, so she left it covered while she worked on identifying the parts of the cerebrum. Sheep don't have a large frontal lobe--I guess they don't do a lot of planning?

Between these two photos you should be able to identify the parietal, occipital, and temporal lobes, as well as easily see the gyri and sulci and the longitudinal fissure:

Okay, time to expose the cerebellum and cut the brain in half! Will cut the cerebrum down the longitudinal fissure, but the cerebellum doesn't have the fissure, so she just had to carefully slice it in half:

She's cut through the corpus callosum, so the sheep should be seizure-free now... if, you know, it had survived:

Some of the ventricles are harder to identify, but you can use the corpus callosum to help you identify the lateral ventricle. It was interesting to me how much of the visual identification of these parts relies on very minute color, texture, or physical changes. That's something that you might not think about if you only look at diagrams of the brain with everything color-coded like a map!

With the brain cut in half, Will was able to identify the superior and inferior colliculi, the pineal and pituitary glands, and the midbrain, pons, and medulla oblongata on the brain stem.

The nerves were harder to find, especially as Will had accidentally removed the optic chiasm with the dura mater (oops!), but you can't miss the olfactory bulbs!

To get really familiar with the parts of the brain, one really ought to dissect lots of brains, and lots of different types of brains. This singular dissection, however, suits both Will's needs for AP Psychology and our kitchen table venue. Interestingly, there's not an AP Anatomy and Physiology exam offered, so I doubt that Will's dissection needs will expand much beyond the singular organ or very small animal (the kitchen table has already handled a shark dissection, after all!).

If she wants to study more advanced life sciences, however, particularly anatomy and physiology, our local university has a program that allows successful high school applicants admission to their lower-level classes. I'm sure there's some grad student somewhere who would just LOVE to teach Will and a whole lab of her +2 peers alllllll about how to dissect all of the things!

Will and I both found video demonstrations to be MUCH more helpful than a written walk-through, but if you're looking for even more resources, there are some written descriptions here:

  • anatomy and physiology dissection. This guide IS geared to an anatomy and physiology class, so has several more parts to identify than the most basic dissection guides. If you're going through the time, expense, and trouble of a sheep brain dissection, you might as well get the most out of it!
  • dissection lab manual. The photos here are very good--much better than that dissection manual I checked out of the library, humph!
  • multi-grade sheep dissection. Here are some activities to guide much younger students through a sheep brain dissection. 

No comments: