H.5.4


 * //Outline atherosclerosis and the causes of coronary thrombosis.//**


 * Atherosclerosis** is a **degenerative disease** of large and mediums sized arteries. It occurs when deposits of lipids (cholesterol, saturated fats) build up in the inner lining of an artery. This buildup, called plaque, attracts phagocytes. They release growth factors that stimulate muscle and fibrous tissues in the artery wall to thicken. This affects the blood flow to the heart. The growth of wall tissue causes the artery wall to bulge inwards which //reduces or prevents the flow of blood//. When this occurs in the certain parts of the body, like the legs, the blood can simply reroute itself through other arteries or arterioles. The buildup of plaque can also induce blood clot formation in the arteries. If a clot forms, it may block the artery or the clot alternatively may become dislodged and travel to smaller arteries which it will block.

When this blockage occurs in a //coronary artery//, the blood flow to the cardiac muscles and other areas of the heart are impaired and sometimes even completely stopped. This is called **coronary thrombosis**, which is also known as a **myocardial infarction** or **heart attack**. A clot formed in the coronary arteries, lungs or brain can lead to a stroke or heart attack.