The Cardiovascular System
David Clarke is 30 years old, stands 6’ and weights 225 lbs. He commutes between Miami where he is a full time student, and Hialeah, where he works as a paramedic. He sleeps only two to four hours per night. Brian is overweight and does very little exercise. He also admits to eating mostly fatty foods. Both David’s grandmother and father have suffered heart attacks. According to new statistics, “despite the recent decline in mortality from coronary heart disease, this disease remains the leading killer of US adults of all ages” (Rubin JB 1). Heart disease is the result of poor diet, lack of exercise, stress and a host of others which is why David Clarke should be concerned. With his current lifestyle Brian may be or become one of 27.1 million Americans with heart disease (Heart Disease par. 1). Coronary heart disease is a disease of the blood vessels supplying the heart muscle. This is just one disease out of many that may emerge within the much larger cardiovascular system. This system consists of the organs and tissues involved in circulating blood and lymph (white blood cells) through the body. New studies showed that donor stem cells taken from adult bone marrow were found to be just as effective in treating diseased hearts as injecting patents with their own stem cells (“Donor Stem Cells Just As Good For Heart Patients” par. 2). The advantage of using donor stem cells is it reduces the time taken to prepare the large quantities of cells thus cutting down on waiting time considerably. Cardiologists have been able to understand the function on the cardiovascular system in order to develop and discover new prevention methods, heart disease and future prognosis. Blood that is high in carbon dioxide is pumped from the right side of the heart to the lungs. Here at the lungs the blood is oxygenated and taken back to the left side of the heart. As the right ventricle of the heart contracts deoxygenated blood is pumped through the pulmonary semilunar valve and then through the paired pulmonary arteries to the lungs. These pulmonary arteries are the only arteries within the body that pump oxygen-poor blood (Thomson 38). The process in which deoxygenated blood is oxygenated is relatively simple. As the pulmonary arteries enter the lungs they branch out into millions of pulmonary capillaries. Carbon dioxide is then diffused from the red blood cells to the air in the lungs alveoli and oxygen diffuses onto the cells. This oxygenates the blood, a process in which the average person repeats about 20,000 times every 24 hours (Breathing par. 2). As the oxygen-rich blood passes through the capillaries of the lungs it travels back up to the heart via, the only veins that pump oxygenated blood, the pulmonary veins. These veins pour the oxygen rich blood into the left atrium of the heart, ready for utilization of the systemic circuit.
In the systemic circuit oxygenated blood, which is supplied by the pulmonary circuit, is pumped throughout the body from the aorta. Oxygenated blood is pumped to all the organs of the body through systemic arteries and returned to the heart through systemic veins. The oxygenated blood that is dumped into the left atrium from the pulmonary veins is pushed through the left ventricle. This ventricle contracts forcing oxygenated blood to the aorta and out. As soon as the oxygenated blood exits the heart the aorta bends downwards to supply the lower body with blood. To supply the brain and upper portion of the body with blood a group of arteries branch off of the arched aorta to oxygenate this part of the body. In both the brain and the rest of the body these systemic arteries branch off millions of times to form capillaries that are in contact with every single cell in the body (Thomson 2002). These cells get nourished with oxygenated blood and needed nutrients to function. Now the deoxygenated blood must make its way back towards the heart. In a way, the second step of the circuit...
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