This weekend we dissected a sheep’s brain. Dissection is a great way to encourage interest about anatomy and to learn a little more about yourself. We got our specimen’s from Home Science Tools for those interested in trying dissection for themselves.
When dissecting a brain, you might find a sac around it, called dura mater. This is sometimes removed in preservation, but this sac is what holds the cerebral spinal fluid that helps cushion the brain and provide nutrients. The next thing you should notice is the ridges and grooves, called gyri and suci. Brains aren’t flat, and that’s a good thing, because more surface area means more brain power.
Before you cut anything, you can also see the two main parts from the top – the cerebrum and the cerebellum. The bigger section in the front is the cerebrum, which is responsible for “big” thinking, like memories, emotion,s and analytical analysis. The cerebellum is responsible for gross motor skills, moving your muscles. So your cerebrum thinks about going on a walk and the cerebellum tells your legs to move.
Now you flip the brain over. On the body, at the front of the cerebrum you should see the olfactory bulbs on each lobe. These connect to the nose and process smells. Towards the middle, you should see a white x. This is the optic chiasm which processes information from the eyes. Behind that, you might see the tiny spot where the infundibulum was attached, but it was probably removed with the dura mater. This attached the pituitary gland to the brain, so even though you won’t see it, you should talk about it. It’s got an important job regulating reproduction, growth, and temperature. Underneath the cerebellum, you’ll find the medulla oblongata. This is the thing that keeps us alive, as it is responsible for all the things we don’t think about like breathing, heart rate and blood pressure. Before you get to the spinal cord, you’ll see the pons. The pons is responsible for the other senses – hearing, taste, and touch as well as chewing and swallowing. Finally, you’ll see the spinal cord which connects the brain to the rest of the body and help send messages.
Now if you cut the two hemispheres apart, you can see a lot more of the structures inside. Between the infundibulum and the pons, you’ll find the hypothalamus, which controls hunger, thirst, sleep, temperature, and parenting or attachment. Above the hypothalamus is the thalamus, which is the switchboard for the senses. The information comes from all the other areas to here, where it is sent to the part of the brain that needs to know about what was sensed. There is a tiny gland here called the pineal gland, which helps produce melatonin. Melatonin production is determined by light exposure and helps us sleep. In front of the cerebellum is the colliculus. The superior colliculus controls eye movement. The inferior senses sound.
If dissection is something that interests you, we will be dissecting more throughout the year. Keep an eye on our calendar for some other things we might dissect. You may find some other exciting things too. We’ve got potions class, magic class, owl pellet dissection and even a Haunted Museum coming up in October. STEAM storytime all month is focused on the spooky world. We hope to see you for some spooky science.