how does the circulation work (6)

narrowing of the coronary artery limits the amount of oxygen-rich blood reaching the heart muscle. The result may be a chest pain called an angina.

angina is usually experienced during exertion because the heart muscle lacks oxygen so it is forced to respire anaerobically. 

If a fatty plaque in the coronary artery ruptures, cholesterol is released which leads to rapid clot formation. The blood supply to the heart may be completely blocked. The heart muscle supplied by these arteries does not recieve any blood, so it is said to be Ischaemic (without blood).

if the affected muscle cells are starved of oxygen for too long they will be permanently damaged. This is what we call a heart attack or myocardial infarction. If the zone of dead cells occupies only a small area of tissue the heart attack is less likely to prove fatal.

If the supply of blood to the brain is only briefly interrupted then a mini-stroke may occur.

a mini-stroke has all the symptoms of a full stroke but the effects only last for a short period, and full recovery can happen quite quickly.

However a mini-stroke is a warning of problems with blood supply to the brain that could result in a full stroke in the future.

first signs are often shortness of breath and angina.

symptoms of angina are often intense pain and a feeling of constriction or discomfort in the chest or left arm or shoulder.

other symptoms are very similar to severe indigestion and include a feeling of heaviness, pain and pressure.

sometimes CHD causes the heart to beat irregularly, this is called an arrhythmia  and can itself lead to heart failure.

stroke symptoms can vary, symptoms include.

-numbness

-dizziness

-confusion

-slurred speech

-blurred or lost vision in one eye

visible signs include paralysis on one side of the body.