The artery is made of layers, the inner layer is called the endotheliumm its usually smooth & unbroken.
If damage occurs then white blood cells & lipids clump together under the lining to form fatty streaks
Over time more white blood cells, lipids & connective tissue build up & harden to form a fibrous plaque called an artheroma.
The plaque partially blocks the lumen od the artery &restricts the blood flow, which causes blood pressure to increase.
An aneurysm is a balloon-like swelling of the artery.
- Atheroma plaques damage & weakens the arteries. They also narrow arteries, increasing blood pressure.
- When blood travels through a weakened artery at high pressure, it may push the inner layers trhough the outer leastic layer to form a balloon-like swelling - an aneurysm.
- The aneurysm could then burst causing a heamorage.
Thrombosis is the formation of a blood clot.
- Atheroma plaque can rupture the endotehlium of an artery.
- This damages the arterywall & leaves a rough surface.
- Platelets & fibrin build at the site of damage and form a blood clot.
- The clot can become a complete blockage over time, or it can become dislodged & block a blood vessel elsewhere in the body.
- Debris form the repture can cause another bloode clot to form further down the artery.
Myocardial Infarction - Heart Attack
The heart muscles is supplied with blood by the coronary arteries.
The blood contains oxygen needed by the heart muscle cells to carry out respiration. If the coronary artery beocme completely blocked and area of the heart muscle will be totally cut off from its blood supply, recieving no oxygen.
This causes a heart attack.
A heart attack can cause damage and death to the herat muscle.
Symptoms inculde pain in the chest & upper body, shortness of breath & sweating.
If large areas of th heart are affected complete heart failure can occur.
Risk of Coronary Heart Disease.
High Blood Cholesterol & Poor Diet.
If an individual has a high blood cholesterol level it can cuase fatty deposits to build up and this causes an atheroma.
Atheroma's lead to blood clots and high bp.
This could block the flow of blood to the heart and cause a heart attack.
A diet which is high in saturated fat is also associated with high blood cholestreol levels .
A diet high in salt also increases the risk of cardiovascular disease because it increases the risk of high bp.
Risks of Coronary Heart Disease.
Both CO & nicotine, found in cigarette smoke, increase the risk of CHD.
CO combines with haemoglobin and reduces the amount of oxygen transported in the blood, & so reduces the amount of oxygen available to tissues.
If the heart muscle doesn't recieve enough oxygen then a heart attack can occur.
Smoking also decreases the amount of antioxidants in the blood - these are important for protecting cells from damage. Fewer antioxidants means cell damage in the coronary artery walls is more likely, & this can lead to an atheroma formation.
Risk of Coronary Heart Disease
High Blood Pressure.
High bp increase the risk of damage to the artery walls.
Damaged walls have an increased risk of atheroma formation, causing a further increase in bp.
Atheroma's form blood clots and then blood clots could block flow of blood to the heart muscle, possibly reuslting in a heart attack.
So anything that increase risk of high bp can increase the risk of CHD, being overweightm not exercising & execessive alcohol consumption.