The heart is an organ that is responsible for pumping blood around the body, to all of the tissues. In humans, there is a double circulatory system which means that the blood returns to the heart after passing to the lungs to be oxygenated so that it can be sent to the rest of the body, this is to ensure that there is enough blood pressure to pump blood to all of the tissues and organs. Problems begin to arise when the heart becomes damaged or the vessels it is associated with become damaged. This can arise in a number of different ways.
This occurs when fatty deposits build up within arterial walls. White blood cells that have taken up low density lipoproteins result in fatty streaks within the walls, these streaks build up over time. When the streaks enlarge over a long period of time they form what is known as an atheromatous plaque. The deposits push into the lumen, causing it to narrow, reducing blood flow. Atheromas increase the risk of thrombosis and aneurysm.
When an atheroma breaks through the endothelium lining it increases friction at the surface of the lumen which can result in a blood clot, a thrombus. This reduces blood supply, leading to tissue on the other side of the clot being deprived of oxygen, glucose and other nutrients essential for its survival and as a result the tissue dies.
Atheromas weaken arterial walls, the weaker points lead to a balloon like, blood filled structure known as an aneurysm. Aneurysms burst frequently, leading to haemorrhage and lead to a loss of blood to the region of the body served by that artery.
4. Myocardial Infarction
This is known as a heart attack, this results in a reduced supply of oxygen to the heart. This can lead to the heart stopping beating as its blood supply is completely cut off. The heart stops beating as it is at risk of dying. It is caused by thrombosis and atheromas.