Throughout the body, blood is transported through vessels (arteries, veins and capillaries). Within the arteries (biggest vessels), different factors can cause the build up of cholesterol in the wall of the artery, this is ATHEROSCLEROSIS. The cholesterol build up is called an ATHEROMA and it makes vessel diameter becomes smaller. This results in high blood pressure as more blood is trying to squeeze through the vessel through a small space. The blood pressure damages the artery because it is not built for that pressure and the atheroma becomes an atherosclerotic plaque. This plaque has a fibrotic cap that protects it
Constant high blood pressure over a long time can wear away this cap and cause the plaque to burst/rupture. This then trigger a blood clotting, which forms over the plaque. This blood clot is called a THROMBUS. The thrombus then blocks the rest of the vessel and stops blood getting through. If this happens in the coronary arteries (the arteries that supply the heart with oxygen) then it causes a heart attack. Whereas, if it happens in the brain it causes a stroke.
Thrombi can dislodge and travel around the body. This is called an EMBOLUS. An example is it can travel from the leg to the lungs and blocks blood flow here.
There are lots of different causes that can cause thrombosis:Age, Diet, Diseases, Obesity Genetics, Exercise, Gender, Smoking