Organ Systems & Evolution Assignment Example | Topics and Well Written Essays - 1000 words

Organ Systems & Evolution - Assignment Example The circulatory and lymphatic systems are also connected, for lymph in the lymphatic system comes from blood. Lastly, secondary lymphedema, an obstruction of lymph flow, is discussed with its similarities to atherosclerosis. Atherosclerosis and Heart Attack Normally, the heart supplies oxygen to all parts of the body to keep them alive, and at the same time, oxygen-rich blood must be supplied to the heart muscle to keep it alive. However, in the case of atherosclerosis, or the buildup of plaque in the arterial walls, the flow of oxygen-rich blood to a particular section of a heart muscle, or myocardium, can get blocked. If the blood supply to the heart muscle is greatly reduced or completely prevented, it will eventually cause the muscle to die. Although there could be other causes for a heart attack, the one caused by this buildup of plaque, or atherosclerosis, is known as coronary heart disease, or CHD (â€Å"What is a Heart Attack,† NIH, 2011). The reason behind the name is the fact that the coronary artery is responsible for the supply of oxygen to the heart. (Matthews, 2011) Coronary heart disease is caused by the buildup of plaque for many years, and will most likely lead to a heart attack. As plaque accumulates in the wall of the artery which supplies oxygen-rich blood to the heart, this plaque may cause a rupture inside the artery and thus cause a blood clot to form on the surface of the plaque. If this plaque grows in size and becomes large enough, it may completely block all blood flow to the heart muscle (â€Å"What is a Heart Attack,† NIH, 2011). The complete obstruction of the blood will cause a myocardial infarction, or heart attack. However, partial blockage may only cause chest pain. (Matthews, 2011) Heart attacks may not kill the person and may simply cause heart failure. Heart failure can lead to other problems like dyspnea, or shortness of breath, and edema, or swelling of the body due to buildup of fluid the heart would normall y get rid of as waste if it were functioning efficiently. (Sourfer, 2002) Arteries, Veins and Capillaries Blood vessels are hollow tubes that do not only hold the blood within the body but also circulate them across organs in the body. There are three types or varieties of blood vessels. The arteries transport oxygenated blood away from the heart. The capillaries are the ones that connect the arteries and the veins, and finally the veins carry the deoxygenated blood back to the heart. (â€Å"Blood Vessels,† 2011) The main function of arteries is to carry blood from the heart to all the other organs, except for the pulmonary arteries that carry deoxygenated blood towards the lungs. Arteries are thick-walled blood vessels and thus may be able to withstand constant stretching every time blood rushes through them for every heartbeat. The thick walls of the artery protect it from the high pressure of blood flow coming from the ventricles of the heart. (â€Å"Blood Vessels,† 2000) Veins, on the other hand, may undergo less pressure coming from the blood flow from organs. It also follows that the wall of a vein is thinner than that of an artery. The function of veins is generally to carry deoxygenated blood from the organs towards the heart, except for pulmonary veins that carry oxygenated blood from the lungs towards the heart. Moreover, veins have a special purpose of carrying waste