Pig Heart Dissection
On the first day, we watched Mr. B-R showed us the dissection of the right side of the heart so we know what to do when we dissect it. He measured its weight and its volume. To measure its weight he just put it on a weighing scale, my estimate was 700 grams, the real weight was 380 grams. To measure the volume, he filled a beaker with water, put the beaker in a tub and dropped the heart in. then he measured the amount of water in the tub. This is called displacement. My estimate of the volume was 400 milliliters, its real volume was 345 milliliters.
On the second day, we did the dissecting:
First look: before dissecting. We could see that the right side is smaller than the left side, it doesn’t really reach down to the bottom of the heart, the left occupies the bottom of the heart. The left side was a lot denser than the right side. The pulmonary artery and the aorta were quite rubbery and pink on the outside and we found out that its true color is white (we see this when we cut in). The heart had some fat on the outside, it looked quite pinky white. It had a very smooth texture. You could see the vein between the left side and the right side.
Cutting in. there was some blood in our heart so we had to drain it first. Then we started cutting down the pulmonary artery. At the top there were some valves, these would fill up with blood and close up so that the opening would close and the blood is forced through another opening. The valves are quite elastic and thin. Then we cut down the side of the right side right to the bottom, as far as the right side could go. To cut, we needed the scissors to find its way on its own because if we force it or poke it, the dissection would be ruined. When we got to the bottom, we turned around and went back up so that the right side would open completely. Inside the right side, there were a lot of blood clots, mainly around the middle valves. The blood clots were very dark red and they were squidgy. We used tweezers to get them out. We tried pulling the valves to see how they work. They were the same as the top valves. The wall of the right side was around 5 millimeters thick. Our atriums were cut off so we couldn’t really see it properly. There were some valves up there too.
On the left side, it was a lot harder to cut. This is because the wall was about 4 times as thick as the right side and it was denser. We did the same thing with the cutting, going down to the bottom and coming back up, letting the scissors find its way. The inside was smooth but it had a lot of vertical dents. There were a lot of blood clots as well, these were harder to get out. The valves were in the same places. The left side seemed a lot stronger with a lot more muscle. The wall between the left and right side was quite thick. We got a bit confused about where to cut from with the left side because people around us had hearts with atriums.
Flow chart of the blood cycle: The deoxygenated blood returns from the body throught the vena cava à it then gets pumped out from the heart to the lungs through the pulmonary artery à in the lungs, the blood does gas exchange to get rid of the carbon dioxide and receive oxygen à the blood then comes back to the heart through the pulmonary vein à the blood filled with oxygen is then pumped out of the heart through the aorta to the body so that the body can take the oxygen away from the blood and use it for respiration à from respiration, the blood carries the waste: carbon dioxide and brings it back to the heart through the vena cava.