Tuesday, March 09, 2004

Matter

Today at the end of functional neuroanatomy I got to see a real (dead) human brain. A pathologist is auditing the class and arranged with the professor to show us what an actual brain looks like. After looking at so many text book diagrams it's easy to think in terms of color keys and labels when in actuality the brain is NOT color coded and it's VERY difficult to determine boundaries between brain areas. It was awesome. He had the whole brain (cerebrum, cerebellum and brainstem) of a 3 year old (died due to congenital leukemia) and the brainstem of a 50 year old who died of breast cancer. (NOTE: It's hard for some people to get over the fact that the brain was from a human who lived and walked and talked similar to us. I find it easy to get excited about the opportunity I have to see and learn. I'm an organ donor and the way I look at it, when I'm dead and gone I won't need any of my body parts ever again. I'm more than happy to donate them to people who can learn from and possibly improve medical techniques as a result.) Anyways I was surprised to find the 3 year old brainstem was nearly exactly the same size as the 50 year old brainstem. The cranial nerves were amazingly visible (and right where the text said they should be!) and the optic chiasm was incredible. The pathologist had sectioned the brain into 15 or so slices (cutting top to bottom from the front to the back like a loaf of bread.) It was so neat to see the striatum, thalamus, LGN, and so many other structures I've only seen in diagrams and MRI's. The ventricles were beautiful. I am completely blown away by how many intricate levels of organization are compacted into such a SMALL space. The incredible organization of the cerebellum was so obvious. It's an engineer's dream. He had it partially sectioned so that we could look inside without the whole structure coming apart. It was a really awesome experience. (NOTE (again): some people think of the brain in terms of what they've seen in horror movies or bloody murder scenes. The scientifically preserved brain is really SO different and I don't see how anyone could really be repulsed by it. It's clean, heavy, dense tissue that has darker "gray" brown areas and lighter "white" areas. It's really beautiful.) Please check this out! It's not bad at all. I promise! Some links to BRAIN pictures: Through the middle Front of the head is towards the left, back of the head is towards the right. The lighter, curved, banana-type thing in the center is the corpus callosum. It's the fiber tract that connects the left and right hemispheres of the brain. Side to side The lateral ventricles (they hold cerebral spinal fluid (CSF)) are the butterfly shaped holes in the center. The ears would be on the left and right sides of this picture. Ventricles Here's a schematic of the ventricles and their position within the brain. You can see the large lateral ventricles (Backwards C shaped; one in each hemisphere) and the third ventricle underneath. The 4th ventricle is the smallest, lowest one, next to the cerebellum. Some labels More structures in a section similar to the second picture. OK That's probably enough for now. Can you tell I love this stuff? =)

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