Atherosclerosis
- There are a number of diseases of the heart, or cardiovascular diseases, that can affect blood vessels in different ways
- Atherosclerosis, also known as hardening of the arteries, is caused primarily by damage to the delicate endothelium of an artery followed by an inflammatory response
- It is a progressive disease, meaning that it can worsen over time
- In a healthy artery the endothelium is smooth and unbroken to reduce friction between blood and the inside if the artery
- The steps involved in atherosclerosis are
- Damage, e.g. by high blood pressure, is caused to the endothelium
- Damage can also occur as a result of high levels of certain types of cholesterol, smoking, diabetes, obesity, and old age
- An inflammatory response occurs and white blood cells such as macrophages accumulate in the damaged area
- Lipids and cholesterol clump together with the macrophages under the endothelium and form fatty streaks
- This is one of the first signs of atherosclerosis
- Platelets can also add to the fatty deposit
- Platelets are fragments of red blood cells involved in the blood clotting process
- The collection of cholesterol, lipids, macrophages and platelets accumulate under the endothelium
- The structure forms a plaque known as an atheroma
- The atheroma narrows the lumen of the artery, reducing and restricting blood flow and thereby raising blood pressure
- Over time, the plaque can calcify and harden, reducing elasticity of the artery wall and further increasing blood pressure
- Damage, e.g. by high blood pressure, is caused to the endothelium
Atherosclerosis is the process by which atheroma plaques form in the endothelium of arteries