This post contains images of a heart dissection. There is no blood in the heart or in these pictures, but there are several close up images of the dissected heart and muscular cells!
When Kat and I were learning about the heart and cardiovascular system, we really wanted to get an in-depth understanding of the human heart and how it works. We had built a model of a pump to mimic a heart, we had made up a circulation game with little blood cell pieces, and we had even made an anatomically correct model of the human heart! What we hadn’t done, was look at a real heart, in the flesh, and see how we learned looked in reality.
For this, we turned to the tried and true method of biological dissection! A biological dissection is a very detailed examination of a deceased (and sometimes preserved) plant or animal. It often involves cutting it open at specific points to get a good look at the inner workings of the organism. Kat is no stranger to doing dissections, as she did her first when she was four years old. She had found a giant crab spider that had perished in our office and wanted to take a look at it. She actually made a fascinating discovery, that spiders have almost metallic looking springs loaded in their pedipalps (pads on their front two legs) that they use in mating!
From then on, she had taken just about every dead insect she could find to dissect! She wanted to know if all of the parts on the inside were the same, and what they were for. As we later learned about the anatomy of mammals, she wanted to know why the parts were different for insects and other animals! She’s always been wanting to take a deeper look. Sometimes, facilitating this desire has made me pause to take a deep breath, as the dissections get more and more involved.
In the case of the bat dissection, it was the first time I had any hesitation. I didn’t let her on to it, as I wanted her to fully experience and explore her curiosity without adopting my opinion of it. It was, admittedly, a bit difficult at first, to watch her cut open a cute little bat specimen. However, she loved it, and was absolutely fascinated by how everything inside the bat matched what she had seen in pictures of our own anatomy! She could see the lungs, the heart, the intestines, everything! It was all right there, opened up in this world of biological wonder to a little girl.
So now we had dissected insects and arthropods of all kinds, she had dissected a cow’s eye to learn about the inner workings of the eye, she had dissected a bat, observed a turtle dissection, and she had even dissected a dog shark! But we hadn’t quite dissected anything that was really similar to something you would find in a human. When we were learning about the heart and the cardiovascular system, we found ourselves with the perfect opportunity to do so!
I ordered a pig heart from Carolina Biological Supply Company. For only $10.00, this kit came with the heart, a teacher and student guide, a dissection tray, scissors, magnifying glass, forceps (similar to giant plastic tweezers), a ruler, probe, and safety goggles! It had just about everything we needed to do our dissection! We had some disposable scalpels on hand in the house, so we added those to our kit and we were ready to go!
Once we had our dissection kit in hand, it was time to crack it open and get to work! This time, I decided to invite a friend along for the fun. She is a licensed EMT, volunteers at the American Red Cross, is studying medicine, and absolutely loves anatomy and biology! Once we had our dissection team in place, we were ready to go!
Kat took charge with a scalpel in hand, as she made the first cut into the heart. The first incision was made into the left ventricle. Kat was surprised by just how thick the muscle of the heart was! It was much harder to cut through than anything she had dissected before. Beverly gave expert guidance while she was cutting, and explained why our heart muscle is indeed so thick, that the machinery of our heart operates constantly for the duration of our entire lives, directing the flow of blood through miles of veins arteries!
After cutting through the thick muscular walls of the heart, we were finally able to get inside the ventricle. What we found in there was fascinating! Inside each ventricle, attached the walls of the heart, are these tiny tendons that pull the valves open when the heart contracts! It was fascinating to get a look at the connected pieces of this complex piece of machinery.
When we learned about the intricacies of how the heart works to pull the valves open to pump blood out, we, of course, wanted to check out the valve to see what it actually looked like! Kat cut right into the left atrium on her quest to find the valve. With some help with Beverly (again, those muscles are thick!), we were finally able to get it open.
There were so many interesting things to cut into in the heart! The teacher and student guide from Carolina came with instructions on where to cut on the heart and what to look for. This was great for the beginning moments of our dissection! However, like so many things on our learning adventures, we quickly found that our own curiosities were best pursued. For instance, on the left side of the heart, near the atrium, we found this strange flap. Naturally, our first response was to cut deeper to see what was underneath. What we found was fascinating!
This is an auricle, and it sits on top of the left atrium, collecting oxygenated blood as it leaves the lungs, before depositing it in the ventricle so it can continue its cycle through the heart and body! All of that mass of tissue is normally filled with the oxygen-rich blood our bodies need to function properly. There is an auricle on the other side of the heart as well. The right auricle fills with deoxygenated blood, before dropping it off into the right ventricle so it can be pumped back into the lungs to collect more oxygen.
One of the coolest things we found while we were dissecting the heart, was that the heart is filled with so many nerve cells! Some of them are large enough that you can actually see them! We cut open the aorta, so we could see what the tissues looked like inside the largest artery in the body. What we found were regularly spaced bundles of nerve cells!
For me personally, this was the most exciting part of our heart dissection. There were real bundles of nerves, right there! In hindsight, I really should have sliced a sample of nerve cells to look at under the microscope. I’m going to have to keep an eye out for another heart dissection (perhaps at our Arizona Science Center), and see if I can snag a sample. I did, however, manage to slice off portions of the heart muscles, so we could take a look at these under the microscope! I had almost purchased my own set of prepared heart muscle slides, but decided to try to make my own instead. Not only was it very easy to do (you just slice VERY thin pieces of the tissue), but the clarity was fantastic!
Doing a heart dissection was such a fantastic way to really gain insight into the inner workings of the heart. We had spent so much time learning about it, making our models, and drawing diagrams, but really getting to look at how it all connected together in the flesh, made our understanding of it that much greater. Being able to conduct our dissection under the tutelage of our wonderful friend and certified EMT, Beverly Tryk, made the experience all the more incredible, as every question could be answered with precise detail right then and there!
I am so excited that we are able to pursue our interests in biology so fully like this! Being able to really see everything we learned about the heart was absolutely invaluable to our understanding of it. It’s one thing to look at labels on a diagram, it’s another thing entirely to put our own labels on a real heart, and see everything right there in front of us! Every bit of recognition was like a light going off, where we were able to understand how different pieces of the heart worked together, and how it worked within us to keep us alive and healthy, beat by beat, through our entire lives. Of course, it’s also really FUN! I can’t wait to do it again.
We bought our dissection kit from Carolina Biological Supply. This company has several dissection kits that are under or around $10 and come with everything you need to do your dissection! The specimens are preserved using their special “Caro fluid” which does not use formaldehyde. On a personal note, I HIGHLY recommend going through them, as their selection is huge and low priced, their service is prompt, their customer service is responsive, and their teaching materials have been trusted by science institutions for many years.