Heart disease

Aim To review cardiac cycle with an exam question To understand how atheroma and thrombosis can lead to heart attacks To learn what an aneurism is To make notes on risk factors for coronary heart disease.

To start……… Complete the heart question 1 page 98 in the text book

A cross section through an artery outer layer of connective tissue middle layer of smooth muscle & connective tissue inner layer (endothelium)

Plaque forming in artery a outer layer middle layer endothelium fibres fat-laden cells (cells that have taken up triglycerides and cholesterol) Lumen of artery b blood clot (thrombus) due to damage of endothelium of artery

Atheroma…some words to help White blood cells fibrous plaque endothelium low density lipoprotein

Atheroma bursts through endothelium of artery This damages artery wall leaving a rough surface Platelets and fibrin accumulate causing a blood clot (thrombosis) Blood clot may block artery or become dislodged blocking a blood vessel elsewhere Debris from the rupture can cause another clot to form

Cross section through a normal coronary artery. The lumen is large,without any narrowing by atheromatous plaque. The muscular arterial wall is of normal proportion.

The coronary artery shown here has narrowing of the lumen due to build up of atherosclerotic plaque. Severe narrowing can lead to angina, and infarction.

This distal portion of coronary artery shows significant narrowing. This is typical of severe coronary atherosclerosis. This would make a coronary bypass operation difficult.

There is a pink to red recent thrombosis in this narrowed coronary artery.

The coronary artery extends from left to right across the middle of the picture and is surrounded by epicardial fat. Increased epicardial fat correlates with increasing total body fat. There is a lot of fat here, suggesting one risk factor for atherosclerosis. This coronary shows only mild atherosclerosis,

Here is an example of an atherosclerotic aneurysm of the aorta in which a large "bulge" appears. just Such aneurysms are prone to rupture when they reach about 6 to 7 cm in size. They may be felt on physical examination as a pulsatile mass in the abdomen.

Normal heart muscle

Cardiac Muscle

Myocardial Infarction Aorta Coronary artery Blockage here causes death of a small area of cardiac muscle Blockage here causes death of a large area of cardiac muscle (a)(b) (a) the heart muscle is supplied by coronary arteries (b) blockage of coronary arteries will lead to death of heart muscle (myocardial infarction)

Some definitions to check : Atheroma Thrombus Aneurysm Myocardial infarction LDL

Risk factors You need to make some short notes about the risk factors associated with CHD. In particular … Diet Blood cholesterol Cigarette smoking High blood pressure