Circulatory System - Dissection of a fetal pig


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Circulatory System - Dissection of a fetal pig

  1. 1. Start date: 4/5/12End date: 4/6/12Project members: Naheen, Kyle, Mesha, Amna, SandhyaTeacher’s name: Mr. GreenBackground Information:All organisms must exchange materials within their environment, including nutrients and wastes, suchas oxygen and carbon dioxide. Also known as the cardiovascular system, the circulatory system iscomposed of the heart, arteries, and veins. There are four chambers in the heart, two atria and twoventricles (right and left). The right atrium receives deoxygenated blood from the body (high in carbondioxide) and sends it to the right ventricle, which pumps the blood through the pulmonary arteries.These arteries lead to the lungs, which oxygenate the blood and sends it to the left atrium. Afterflowing into the left ventricle, the aorta pumps the oxygenated blood to all body cells. This system isessential for moving nutrients and wastes to and from cells and therefore, maintaining homeostasis.In this investigation, we will discover how the circulatory system can be observed in fetal pigs.
  2. 2. Purpose: How can we observe the circulatory system of the human body in fetal pigs?Hypothesis: If we believe that fetal pigs are mammals with similar body forms and organs as humans, then we shouldbe able to observe the organs of the circulatory system in the body of the fetal pig and how it functions.Materials:•Fetal pig•Dissecting tools (scalpel, scissors, probe)•Disposable gloves•CameraProcedure:1.) Place the fetal pig on its back in the dissecting pan.2.) Tie a cord around one forelimb, and then bring the cord around underneath the pan to fasten back the otherforelimb.3.) Spread the hind limbs the same way.4.) With the scissors always pointing up, make incisions to expose the thoracic and abdominal cavities.5.) Cut up from the diaphragm until you reach the hairs in the throat region.6.) Make two lateral cuts, one on each side of the midline incision anterior to the forelimbs.
  3. 3. 7.) Make two lateral cuts, one on each side of the midline just posterior to the forelimbs and anterior to thediaphragm, following the ends of the ribs. Pull back the flaps created by these cuts to expose the thoracic cavity.8.) Once the blood vessels of the circulatory system (in the thoracic cavity) have been identified, remove the heartfrom the cavity and cut it open.9.) Identify the chambers and valves of the heart.Observations: Fetal pig Thoracic cavity and other organs exposed
  4. 4. Back of heart
  5. 5. Dissection of the heartFront of heart
  6. 6. Blood Vessels Type of Blood Organ or StructureObserved Carried Serviced by Blood VesselSuperior/Inferior Vena Deoxygenated Heart (right atrium)CavaPulmonary arteries Deoxygenated Right ventricle to lungsAortic trunk Oxygenated Left ventricle to bodyCarotid arteries Oxygenated Heart to head and neckJugular veins Deoxygenated Head to heartRenal arteries/veins Oxygenated Blood to kidneys
  7. 7. Analysis:In this lab, I was able to observe the human circulatory system in a fetal pig. The purpose of the circulatory system is totransport blood to deliver important substances, such as oxygen, to body cells and remove wastes, such as carbondioxide. The heart pumps blood through a vast network of tubes, known as the blood vessels. Blood also carriesdisease fighting materials for the immune system and distributes heat to regulate body temperature. Arteries carryoxygenated blood away from the heart. They are strong, thick walled vessels that are elastic and durable. Arteriesneed to be capable of high pressure because of the force of the blood being pumped away from the heart. Their outerlayer consists of connective tissue, with smooth muscle in the middle layer and endothelial tissue in the inner layer.Veins bring deoxygenated blood to the heart and have thinner walls, since they are driven by blood circulation. Thepulmonary arteries carry blood that is high in carbon dioxide away from the right ventricle and into the lungs. Theaorta is the largest blood vessel in the body and the left ventricle uses it to send blood to body cells. The pacemaker,also known as the sinatrial, is located in the right atrium and receives information about the body’s oxygen levels. Ifdetected low, it will adjust the heartbeat rate (faster).The chamber with the thickest walls is the left ventricle, because it has to propel blood into the systemic circuit. Theright ventricle only sends deoxygenated blood to the lungs and the atria only have the empty the ventricles. Whendissecting the pig and observing the heart, it can be noticed that the pulmonary veins were colored red. This isbecause the pigs were injected with dye. Since the pulmonary veins carry deoxygenated blood, it would make sensefor this blood to be blue. In order to differentiate between arteries and veins without being able to see the colors ofthe blood, it is essential to notice that veins are thinner and send blood to the heart. Arteries are much thicker andsend blood away from the heart.
  8. 8. Conclusion:In conclusion, my hypothesis was correct. We can accurately observe the human circulatory system in afetal pig. During this investigation, I was able to observe several organs and their properties, whosefunctions take place actively in our bodies.Fetal pigs are often used in classroom dissections. These mammals have similar hair, organ systems,metabolic levels, and body forms as humans. Their soft tissue and underdeveloped bones (cartilage)make them easier to dissect than other organisms. The circulatory system of a fetal pig is different fromthat of an adult pig because there is a shunt between the wall of the right and left atrium, which wouldallow blood to pass directly from the right atrium to the left. This closes shortly after birth.I was able to learn countless things during this lab. When dissecting a fetal pig, it is important to havepatience when handling the equipment and making incisions on organs. Accidental incisions can resultin damaging organs of the specimen.