AS AQA Biology - Cardiovascular Disease Part 1

What is atheroma formation?

The artery is made up of lots of layers. It's inner lining is smooth and unbroken -  the endothelium.

However, if this endothelium is to break (to be damaged), fatty streaks can be formed. These fatty streaks are made up of by white blood cells and lipids from the blood coming together.

High blood pressure can be a cause of damage to the endothelium.

After a while, more white blood cells and more lipids and connective tissue will build up. This will harden and form a fibrous plaque - known as an atheroma.

This plaque can block the lumen of the artery, meaning that blood flow is restricted. This increases blood pressure, which can be harmful to the body.

What is an aneurysm?

An Aneurysm is when the artery swells like a balloon.

Atheroma damage and weaken arteries. They narrow arteries which again, causes increased blood pressure.

Blood travelling through a weakened artery, when there is high pressure can push the inner layers of the artery out through the outer elastic layer. This causes the balloon like swelling.

This aneurysm (balloon like swelling) can burst and cause a haemorrhage.

What is Thrombosis?

Thrombosis is the formation of a blood clot.

Atheroma plaque can rupture endothelium of an artery.

This damages artery wall, leaving a rough surface. Remember that the endothelium is usually smooth.

Platelets & fibrin build up on the damaged part of the endothelium - forms a blood clot.

Blood clot can cause a blockage of the artery OR it can become dislodged and block a blood vessel in the body, but somewhere else.

The debris from the rupture can cause another blood clot to form.

Blood flow to the heart being interrupted causes Myocardial Infarction.

The coronary arteries supply the heart muscle with blood. The blood contains oxygen, which the heart needs in order to respire.

If it is the coronary artery that is completely blocked then a part of the heart muscle will have no blood supply, so therefore no oxygen.

This causes a myocardial infarction - heart attack!

Heart attacks damage the heart and can be the cause of the death of the heart.

Symptoms: Pain in the chest and the upper body. Shortness of breath. Sweating.

Larger areas of the heart being cut off from the blood supply can cause a complete heart failure, which can be fatal.