We all know that high blood lipid is harmful and that it can easily cause blood vessel blockage and cause brain infarction, so whenever high blood lipid is found during physical examination, we are worried. Whenever high blood lipids are found during medical checkups, we get worried and ask around, but we know very little about it. Today, we will talk about cholesterol in blood lipids. There are two main components in blood lipids, one is triglycerides, which we often mention as fat in blood, and the other component is cholesterol, which is the most harmful for cardiovascular diseases. Cholesterol itself is beneficial, as it is essential for the production of all hormones in our body and for the construction and repair of cellular tissues, but it is also harmful, such as the formation of atherosclerotic plaques. Most heart attacks and brain attacks are caused by the rupture of plaque. How is atherosclerotic plaque formed? Cholesterol in our bloodstream enters the walls of blood vessels, gradually accumulates and undergoes a series of reactions, eventually forming plaques in the blood vessels, which keep growing. Then it will gradually block the blood vessel. It is called chronic occlusion. If it is a sudden rupture of the plaque, platelets will gather quickly and form a blood clot, leading to a blockage of the blood vessel and a brain or heart attack. Both the heart and the brain need blood to provide abundant oxygen as well as other substances to maintain normal life activities. If the blood flow is interrupted when the arteries are occluded, and if the cerebral vessels become occluded, then it will lead to rapid death of neurons and rapid loss of function of brain tissue due to lack of oxygen. When it happens in the heart, there is a myocardial infarction. It is also commonly known as a heart attack. How does the cholesterol in the blood enter the walls of the blood vessels? Our blood vessels are divided into three layers: the outermost is called the outer membrane, the middle is called the middle layer, and the innermost is called the inner membrane. It is very difficult to see with the naked eye and usually needs to be observed under a microscope. Generally speaking, cholesterol has no chance to enter the subcutis because of the tight connection of the endothelial cells. However, cholesterol can enter the endothelium and accumulate gradually because of the damage to the endothelium caused by high blood pressure, diabetes, smoking, etc. The endothelium can be damaged by high blood pressure. With a thick outer membrane and a thin inner membrane, the atherosclerotic plaque can only bulge inward, forming a stenosis. If no program is taken to control the plaque, it will gradually grow until it ruptures or is occluded. In fact, these could have been prevented, and the mechanism of atherosclerotic plaque formation is clear to us, so to reduce the formation of plaque we must first reduce its raw material, which is cholesterol. The lower the cholesterol, the less raw materials for plaque formation, and the harder it will be for plaque to grow. At the same time, we also need to actively control hypertension and diabetes, and live a healthy life, as long as atherosclerosis does not occur, brain infarction and heart attack will rarely occur.