Cardiovascular Mid-unit Summary

In this unit so far, we have learned about the heart(beat), blood composition, blood vessels, and cardiovascular disease. In the hear(beat) lecture, we learned about the structure of the heart and how it beats. We learned that the heart is covered by the pericardium, which secretes a fluid that lubricates the heart and reduces friction. We also talked about the four chambers of the heart , the right atria and ventricle, and the left atria and ventricle. In addition, we learned about the valves that make the blood flow between these chambers. These valves are the tricuspid, bicuspid, and semilunar. Each help to prevent the backflow of blood. What makes the heart beat sound is the cardiac cycle. It is the relaxation and contraction of both the atriums and the ventricles. Everyone knows that heart beats, but the cardiac cycle shows what is going on as the heart is beating. In the blood vessels we learned about how blood vessels have many functions. These functions include the veins carrying blood from tissues to the heart and the arteries carrying blood from the heart to the tissues. We also learned that capillaries are the tiny vessels that connect our arterioles to our venules. When your blood pressure is too high, you are at risk for heart disease.One disease we learned about was atherosclerosis. That is when fatty material deposits on the inside of the blood vessels and the vessel in turn becomes less flexible and it is harder for blood to flow. These blood vessels can become obstructed or pieces can break off and lodge somewhere else. A blood clot can then form. In time, atherosclerosis may cause a stroke or heart attack. When talking about cardiovascular diseases, we discussed heart attacks, atherosclerosis, cholesterol, and other risk factors. A heart attack is caused when the blood supply to the myocardium is severely reduced or stopped which causes damage to the heart cells or even death to the cells. Heart attacks are usually the result of atherosclerosis. Atherosclerosis is chronic inflammation caused by excess sugars and polyunsaturated fat (bad fat). We also learned about the two different types of cholesterol, LDL and HDL. LDL is the bad cholesterol and will stick to the arteries like garbage and HDL is good and cleans up LDL like a garabge truck. We talked about the risk factors and how some of these included lack of exercise, obesity, smoking, diabetes, and much more. In "Strike Against Strokes" one point made is that is is necessary to keep a low blood pressure. When your blood pressure rises, it causes damage to all the blood vessels in the body, which in turn can cause strokes and heart attacks. It is also mentioned that you must keep a proper diet in order to maintain a healthy life style and reduce your risk of a stroke. In the atherosclerosis reading, one point made is that although bad cholesterol (LDL) is one factor of atherosclerosis, there are many of risk factors that contribute.