Damage to the artery lining
Often where the artery subdivides because of turbulance
There is more turbulance when the person has high blood pressure or an injury
high blood pressure caused by factors such as smoking, stress or genetics
LDLs = Low Density Lipoproteins
As these LDLs pass through the arteries they smere cholesterol onto the walls and under the torn lining of the artery forming fatty streaks
The more cholesterol in the body then the more LDLs there will be to smere it onto the walls
Scavengers i.e. Macrophages are attracted to the damage site where they begin to eat the cholesterol thus becoming "foam cells"
They then engulf so much cholesterol that they burst and splatter onto the wall. They then invade the wall and calcify into plaque
Too much LDL = Too many Macrophages
The wall becomes so hardened from the plaque that it turns into an arterial atherosclorosis and then into an aneurysm
Aneurysm - A balloon like swelling of the artery.
The atheroma plaque damages and weakens the arteries as well as narrows it - increasing the blood pressure
when the blood travels through the now weakened artery at high pressure it may push the inner layers of the artery though the outer elastic layer forming a balloon-like swelling (an Aneurysm)
This may burst causing a haemorrhage (bleeding)
Thrombosis (Blood Clots)
Next, platelets are attracted to the damaged tissue and attatch themselves to the plaque creating an even more increased turbulence making it more likely for a blood clot to form. This is a thrombosis.
Thrombosis occurs when the atheroma plaque ruptures the endothelium (inner-layer) of the artery. This damage leaves a rough surface causing the platelets and fibrin to accumulate there forming the blood blot.
The blood clot can cause either complete blockage of the artery or, if it becomes dislodged then it may block a blood vessel elsewhere in the body
Interupted blood flow to the heart can cause a myocardial infarction
i.e. A Heart Attack
The heart muscle is supplied with blood by the coronary arteries. This blood contains the oxygen needed for respiration.
If a coronary artery becomes completely blocked then an area of the heart muscle will be cut off from oxygen thus causing a myocardial infarction
Heart attacks cause damage and death of the heart muscle. If large areas of the heart are affected complete heart failure can occur, which is often fatal
Risk of heart diseases
High blood Cholesterol (poor diet) - The more cholesterol then the more fat will become
smered on the arterial walls and so it is more
likely that an atheroma will form
Cigarette Smoking - Carbon monoxide combines with haemoglobin and reduces the
amount of oxygen transported in the blood and so reduces the
amount of oxygen available to the heart - lack of oxygen to the
heart increases the chance of a heart attack
Smoking also decreases the amount of antioxidants in the blood
which are important for protecting cells from damage
High Blood Pressure - This increases the risk of damage to the cell wall as it causes
more turbulence to the arterial walls