- The wall of the artery is made of many layers.
- The endothelium is usually smooth and unbroken.
- If damage occurs, white blood cells and lipids clump together under the lining.
- Over time more WBC and lipids as well as connective tissues build up and harden to form a plaque called atheroma.
- This plaque partially blocks the lumen of the artery and restrict blood flow, which causes blood pressure to increase.
- Coronary heart disease occurs when the coronary arteries are blocked by atheroma leading to myocardial infraction ( heart attack ).
Aneurysm and Thrombosis
- Atheroma plaques damage and weaken the arteries.
- They also narrow the lumen by blocking it, causing high blood pressure.
- This may push the inner lining through the outer elastic layer to form a balloon like swelling- an aneurysm.
- It can burst, causing bleeding.
- An atheroma plaque can burst through the inner lining of an artery.
- This damages the wall leaving a rough surface.
- Platelet and fibrins gather around the damaged area forming a blood clot, this can block the artery completely.
High Blood Cholesterol and Smoking
- If the blood cholesterol is too high, the risk of cardiovascular diseases is high.
- Cholesterol is one of the main lipids causing Atheroma.
- Atheroma leads to high blood pressure and formation of blood clots.
- This blocks the flow of blood in the arteries.
- Both Nicotine (causes high blood pressure) and Carbon monoxide are found in cigarette.
- Carbon Monoxide combines with Haemoglobin and reduces the saturation of it with oxygen, so it reduces the amount of oxygen available to cells.
- If heart muscles don't receive enough blood, it can lead to heart attack.
- Smoking also reduces antioxidants in blood- they protect cells from damage.