Sheep Heart Dissection Report

Sheep Heart Dissection 2 The purpose of this experiment was to physically observe the heart's structures, which can often be more informative than just reading how the heart's components go together. It was hypothesized that the heart tissue was going to be soft and pliable, making investigation a smooth process. The methods used were simple dissection and observation using a scalpel and a blunt probe. Some general key results found were muscles being tougher than anticipated, and some nearly solid blood vessels, likely caused by plaque and/or the preservation process. It was noted that the smaller veins tended to be more solid than those that were larger in circumference. The general results did not support the hypothesis. The tissue was firm and sturdy, making collapsed vessels and chambers harder to view without opening them with the probe. Sheep Heart Dissection Sheep Heart Dissection 3 The purpose of this experiment was not only to observe with sight, but touch as well. Viewing the specimen's phenotypic characteristics was inevitable, however feeling texture and resilience through touch, during the actual incisions was a different experience. It was hypothesized that the heart tissue was going to be soft and pliable, making investigation a smooth process. The dissection immediately resonated with the topics learned in class, as the heart, and all of its blood vessels were recently covered. Learning the anatomical terminology for heart structures made the instructions easy to follow, and made most aspects easy to identify. Methods The items needed for this experiment included a scalpel, a blunt probe, dissection tray, bench coat pad, and various safety equipment as follows; gloves, apron, safety glasses,and a face mask. The first observations included external structures, like the base, apex, sulci, and ventricles. The external sections of large blood vessels like the superior vena cava were reopened, using a probe for examination. Next, a scalpel was used to make a coronal cut from the apex toward the base, without severing the heart into complete anterior and posterior sections. From this cut the following were observed: myocardium, endocardium, right atrium, right auricle, pectinate muscle, opening of superior and inferior vena cava, opening of the coronary sinus, tricuspid valve, right ventricle, chordae tendineae, papillary muscles, and the pulmonary semilunar valve. Then, the blunt probe was used to find the opening of the coronary sinus, to observe its movement. The pulmonary trunk was then dissected carefully with a scalpel, exposing the pulmonary semilunar valve. The left side of the heart was observed first, including the left atrium, left auricle, bicuspid valve, left ventricle, aortic semilunar valve, and the aorta. The previous structures were then observed on the right side of the heart. After the structures were identified, the dissection was taken a bit Sheep Heart Dissection 4 further, using a scalpel to open many smaller blood vessels on the wall of the heart to observe their internal reminisce. Results The results of the experiment were relatively adequate. Most structures were identified, however it was especially difficult to observe chordae tendineae and papillary muscles on the valves, as these structures are quite small. It was very informational to actually see the anatomy of the heart, not in a diagram or thought out in words. It was also noted in the results that the smaller blood vessels in the heart, especially those on the internal wall of the heart seemed to be almost solid. It was essentially impossible to probe into them, likely caused by general plaque build up during the sheep’s life, or due to the preservation process stiffening the tissues. g A more exposed view of the heart’s wall the layers of the heart’s wall. Observation and probing of the left atria. Photo of myself, conducting the dissection: Sheep Heart Dissection It was surreal dissecting a heart, instead of looking at pictures and diagrams. The main difference in human/sheep anatomy that was observed was size. The sheep heart seemed smaller in general size than human hearts observed in the textbook and instructional videos. The chambers and blood vessels seemed almost identical. The smaller vessels being solid was the most intriguing. It was expected that clear pathways would be observable throughout all blood vessels, but this was not the case. It raises the question of, “Was it just this particular specimen, or is this standard across all alike specimens?” When the left atria was probed, uncovering that it was quite a bit deeper than expected was interesting. Navigating the probe throughout blood vessels was also very interesting, giving a feel for the path that blood follows. This relates directly to the current chapter in the course, as it was learned that blood vessels are in fact, not supposed to be solid. The path that blood takes through the heart was made clear in this chapter, making the probing of the accessible blood vessels even more interesting. It was hypothesized that the heart tissue was going to be soft and pliable, making investigation a smooth process. However, Cardiac muscle was learned to be a lot tougher than originally thought. The preservation process also stiffens tissue, but out of all of the dissections that have been conducted by myself, muscle tissue has been the toughest out of all tissues dissected. 5