Abstract
For this lab report, I will experiment with a sheep heart. Experimenting with sheep hearts prevents causing harm to human beings who might otherwise have been used as the source of the specimen (heart). In addition, the sheep’s heart is deemed suitable because it shares the same structural and functional characteristics as the human heart. In this paper, I will discuss the purpose of this experiment, indicate the methods and procedures used, and give the results of the experiment.
Hypothesis
In the cardiovascular system, the heart is the main organ and it pumps blood through blood vessels, supplying nutrients and oxygen, besides removing metabolic waste from organs. The purpose of this experiment is to observe the blood flow from the right atrium to the vena cava, what happens to the valves in ventricular systole and atrial systole, and how to measure blood pressure. By dissecting the sheep’s heart, it will give us a better understanding of the anatomy and physiology of the heart (Fails & Magee, 2018). The hypothesis after this experiment is to understand the cardiovascular system better by observing the similarities and differences between the human heart and the sheep’s heart and their structural functions.
Methods
Examine both the anterior and posterior surfaces of the heart. Insert the blunt probe into the collapsed superior vena cava into the right atrium and push the probe into the inferior vena cava. Using a scalpel, make a coronal cut from the apex toward the base slicing both auricles but not through the base. Insert the probe into the right atrium finding the coronary sinus; while still in the right atrium, use the probe to explore the pulmonary trunk to the end of the vessel, remove the probe, and then make a longitudinal incision across the pulmonary trunk exposing the pulmonary semilunar valve. Observe and identify the different structures. Lastly, measure the systolic and diastolic blood pressures.
Results
Apex is the point on which the precordium farthest outwards and downwards the sternum, a point where cardiac impulse can be felt. The left ventricle is thicker and pumps the oxygenated blood to all body tissues. The right auricle receives blood with less oxygen from the body tissues through the vena cava (Trifunović‐Zamaklar et al., 2022). Into the correct ventricle, the blood is transported to the lungs. The left auricle gathers oxygenated blood from the lungs to the left ventricle. The coronary sulcus contains a network of veins supplying blood to the cardiovascular muscles and also to the sinus, coronary veins, and coronary supply routes.
Discussion
The experiment was informative since the structural features of the sheep’s heart were identified. The left ventricular muscle was found to be thicker than the right ventricular muscle. The muscle of the left ventricle is responsible for pumping blood through the aorta to other body organs (Berman et al., 2019). The chordae tendineae is a stringy substance holding the bicuspid valve. The heart divider was observed to be wetter and slippery. These vessels are elastic, muscular tubes carrying blood to all parts of the body (Trifunović‐Zamaklar et al., 2022). As such, the elasticity of the vessels protects the heart from shock and too much friction.
The blood flow cycle begins from the inferior vena cava; the blood then enters the right atrium. Thereafter the tricuspid valve opens to allow the blood to flow to the right ventricle where it is then pumped to the lungs, back to the heart, and then to the body organs (Stephenson et al., 2017). It takes place between successive heartbeats constituent to the cardiac cycle involving the opening and closing of the valves, and contraction and relaxation of heart chambers (Zhong et al., 2019). After the return of oxygenated blood into the pneumonic vein, it is pumped via the bicuspid valve to the left ventricle and eventually moves through the aorta to other organs.
In measuring blood pressure using a Sphygmomanometer, the cuff was placed around the stretched and bare upper arm, followed by inflating it until no blood could flow via the brachial artery. This will see the blood flow through the arm, creating a pounding sound, especially during the closure of arteries and inter-collision between the walls of the vessels (Stephenson et al., 2017). Systolic pressure (112mmHg) was read from the Sphygmomanometer as soon as the pounding sound was detected for the first time. The disappearance of the pounding sound marks the beginning of the next blood circulation cycle, where diastolic blood pressure (76mmHg) was measured.
References
Berman, M. N., Tupper, C., & Bhardwaj, A. (2019). Physiology: Left ventricular function. Web.
Fails, A. D., & Magee, C. (2018). Anatomy and physiology of farm animals. John Wiley & Sons.
Luo, J., Duke, T., Chisti, M. J., Kepreotes, E., Kalinowski, V., & Li, J. (2019). Efficacy of high-flow nasal cannula vs standard oxygen therapy or nasal continuous positive airway pressure in children with respiratory distress: a meta-analysis. The Journal of Pediatrics, 215, 199-208. Web.
Stephenson, A., Adams, J. W., & Vaccarezza, M. (2017). The vertebrate heart: An evolutionary perspective. Journal of Anatomy, 231(6), 787-797. Web.
Trifunović‐Zamaklar, D., Jovanović, I., Vratonjić, J., Petrović, O., Paunović, I., Tešić, M., Boričić‐Kostić, M., & Ivanović, B. (2022). The basic heart anatomy and physiology from the cardiologist’s perspective: Toward a better understanding of left ventricular mechanics, systolic, and diastolic function. Journal of Clinical Ultrasound, 50(8), 1026-1040. Web.
Zhong, L., Tan, R. S., & Ghista, D. N. (2019). Anatomy and physiology of the heart. Computational and Mathematical Methods in Cardiovascular Physiology, 3-37. Web.