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