heart disease. aim to review cardiac cycle with an exam question to understand how atheroma and...
TRANSCRIPT
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