Dissection of a Pig Heart Laboratory Report PDF

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Biology lab report from dissection of a pig heart...

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Laboratory Report: Dissection of Pig Heart

1. Figures: Figure 1.1: Exterior Anterior View of a Pig Heart

Right Atrium

Pulmonary Trunk Base Left Atrium

Right Ventricle

Left Ventricle

Apex

Figure 1.2: Exterior Posterior View of a Pig Heart

Left Atrium Pulmonary Artery

Aorta Base

Superior Vena Cava Pulmonary Veins

Right Atrium

Inferior Vena Cava

Left Ventricle

Right Ventricle

Apex

Figure 1.3: Interior Posterior View of a Pig Heart

Base

Aorta

Right Atrium Tricuspid Valve Chordae Tendinae (Left Side) Septum

Left Atrium Bicuspid (mitral) Valve Chordae Tendinae (Left side)

Right Ventricle Left Ventricle

Apex

Figure 1.4: Interior Anterior View of a Pig Heart

Right Atrium Aorta Left Atrium Bicuspid (Mitral) Valve Chordae Tendinae (Left side)

Tricuspid Valve Chordae Tendinae (Right side) Right Ventricle

Septum

Left Ventricle

Apex

2. Analysis: Investigation Questions: 1) Explain how the appearance of the following structures relates to their function as part of the circulatory system. Give as much detail as possible, including size, texture, external structure, and internal structure a. Right atrium The right atrium is one of the two atria of the heart, which function to receive blood entering the heart. It is located to the right of the left atrium and above the right ventricle, with the tricuspid valve between. The right atrium has muscular walls that are much thinner than the ventricle walls. It also features a wrinkled flap on the outside, which is hollow and extends outward from the frontal surface to increase the right atriums internal volume. These structures are to increase the amount of blood received from the veins and to aid the right atrium in actively pumping blood to the right ventricle. b. Left atrium The left atrium is a small, hollow structure on the left side of the heart that receives oxygenated blood from the pulmonary veins and delivers it to the left ventricle. It is separated from the right atrium by the septum, and from the left ventricle by the bicuspid (mitral) valve. It has a thin pouch of cardiac tissue extending along the left atriums anterior side to increase the volume and capacity of blood that can be held. It is much weaker and thinner than the left ventricle. It is also made up of three layers. The first layer is to secrete lubricating fluid to smooth and protect the heart. The next layer contains cardiac muscle cells to produce the pumping force of the left atrium. The innermost layer prevents the blood cells from sticking to the hearts walls and forming blood clots. c.

Right ventricle The right ventricle is on the right side of the heart, below the right atrium, but above the apex and meets with the left ventricle at the septum. It is much larger than the atria, yet smaller and weaker than the left ventricle. The right ventricle also has the three layers to prevent blood clots, contribute to pumping, and give the heart a smooth outer surface. Blood from the right atrium enters the right ventricle. Once filled with blood, the right ventricles pressure closes the tricuspid valve to prevent regurgitation of blood. It then pumps blood through the pulmonary trunk to travel to the lungs to become oxygenated.

d. Arteries, including the aorta

Arteries are blood vessels that branch into smaller arteries, and carry oxygenated blood away from the heart. They consist of elastic walls so they can expand, specifically if a sudden wave of blood enters during a ventricular contraction. They are also made of three layers. The innermost layer is one cell thick with smooth cells, the middle layer has bands of elastic and smooth muscle tissue, and the outermost layer covers the others with a combination of connective and elastic tissues. The arteries allow blood to continue flowing in the correct direction along with the pumping motion forcing the blood into blood vessels. Specifically the pulmonary arteries are the only blood vessels that carry deoxygenated blood in the body. They carry blood from the right ventricle to the lungs for gas exchange. The aorta is the largest blood vessel in the body. It is thick to stabilize and hold itself. The aorta is responsible for carrying oxygenated blood from the left ventricle to the rest of the body’s tissues. e. Left ventricle The left ventricle is the lower left chamber of the heart. It receives oxygenated blood from the left atrium and pushes it out of the heart to the aorta to be carried to tissues in the body. It has a much thicker and stronger wall than the right ventricle because it pumps blood to all of the body against a great flow of resistance, resulting in a great amount of muscle build-up. f.

Veins Veins carry blood towards the heart. They have a great diameter, and have thin and smooth walls. The pulmonary veins transport oxygenated blood from the lungs to the left atrium. The Vena Cava is the central vein in the circulatory system. It functions by carrying deoxygenated blood to the right atrium from all of the body’s tissues to begin pulmonary circulation. g. Heart valves The heart has four valves. Two of which are called atrioventricular valves, because they are between the atria and ventricles, which let blood flow in one direction. When the blood has flown into the ventricles the pressure becomes stronger on the side of the ventricles, causing the cusps of the valves to close. The tricuspid valve is on the right side of the heart, and lets oxygen-poor blood flow into the right ventricle where it then flows through the pulmonary semilunar valve towards the pulmonary trunk. After the blood becomes oxygenated it flows into the left atrium and through the bicuspid (mitral valve) to the left ventricle. The blood is then pumped to the aorta through the aortic semilunar valve.

2) Using your own drawings and your current understanding of the route that blood takes through the body, trace the movement of blood from the tissues through the heart and back to the tissues. Start with the superior and inferior vena cava.

Deoxygenated blood from the body’s tissues enters the superior vena cava (blood from head, chest, and arms) and inferior vena cava (blood from all other locations in the body), which is then delivered to the right atrium. This blood then flows into the right ventricle through the tricuspid valve. Here it is pumped by the right ventricle trough the pulmonary trunk to the lungs alveoli to become oxygenated. Carbon dioxide leaves the bloods and oxygen from the air in the lungs enters the blood through diffusion. This, now oxygenated, blood then flows through the pulmonary veins into the left atrium, and continues to the left ventricle through the bicuspid valve, where it is then pumped to the aorta to be pumped to the bodies tissues.

3. Conclusion: 3) In what ways was your understanding of the heart and circulation enhanced by your observation of a real heart?

In this lab, the students dissected a pig heart to deepen their understanding of the circulatory system as well as the role of the heart within this system. They were able to tie in their learning from classroom discussions and textbook work into a first-hand learning experience with a pig heart. Being able to see, touch and explore this pig heart helped each student have a stronger understanding of each structure of the heart - specifically their physical characteristics such as; thickness, size, and texture - as well as their functions, resulting in a better general understanding of how the organ works. An example was the ability to use tools and fingers to feed through the arteries and veins to visually see and understand their connections to the heart, and roles within the specific pathways, pulmonary circulation and systemic circulation. Also, this greater knowledge of the circulatory system in a pig can be translated to the human body. The students were able to make comparisons of this dissected pig heart to that of a human, leading to a stronger grasp on the human circulatory system. 4) What experiences did you have that limited your observations or understanding? How could these limitations be overcome? Identified Sources of Error Improvements for Sources of Error Softness of tissue of pig heart: Due to the To improve this error would be to dissect a freshness of the pig heart, the tissue was preserved heart. This would result in a stiffer very soft. This made it difficult to cut into the heart, where the students could make tissue carefully and precisely. Therefore, cleaner, more precise cuts. Therefore, having resulting in jagged cuts that did not a better image of the pig heart and its inner maximize the visibility of the inside structures. structures of the pig heart. Lack of colour distinction: Many parts of the A solution to this error would be to again, heart were similar colours making it difficult dissect a preserved heart that is injected to distinguish between different structures with dye. This way there is an obvious and tissues. Therefore complicating the distinction of the different parts of the pig process of understanding for the students. heart making the observations clearer, resulting in a stronger understanding. Foul smell of organ: The dissection of the pig Again, this could be fixed by dissecting a heart resulted in a strong foul smell preserved heart. This way it would not have throughout the classroom. This distracted the fresh smell of the tissue and juices the students from becoming fully invested in included. Another option would be to allow the dissection due to breaks they had to take the students to bring nose plugs or other from dissecting, and even breaks to exit the accessories to help with the foul smell. classroom....