Unit 2 (K7) - Pathology of Cardiovascular Disease

Question 1

Describe what happens in atherosclerosis.

Answer 1

1. The accumulation of fatty material (consisting of mainly cholesterol), fibrous material and calcium forms an atheroma or plaque beneath the endothelium.
2. As the atheroma grows the artery thickens and loses elasticity.
3. The diameter of the artery becomes reduced and blood flow becomes restricted resulting in increased blood pressure.

Question 2

Which diseases are caused by atherosclerosis?

Answer 2

1. Angina
2. Heart Attack
3. Stroke
4. Peripheral Vascular Disease

Question 3

What is thrombosis?

Answer 3

The formation of blood clots.

Question 4

How can atherosclerosis lead to thrombosis?

Answer 4

1. An atheroma can damage the artery endothelium.
2. This releases clotting factors and a cascade of reactions are triggered leading to conversion of prothrombin and thrombin.
3. Thrombin causes plasma protein fibrinogen to form threads of fibrin.
4. Fibrin forms a thrombus (blood clot).

Question 5

How can thrombosis cause a heart attack?

Answer 5

1. A thrombus (blood clot) formed on an atheroma can break loose creating an embolus and this travels through the blood stream until it blocks a blood vessel.
2. If the vessel blocked is a coronary artery then this may lead to a heart attack (myocardial infarction).
3. Cells are deprived of oxygen leading to death of tissues.

Question 6

How can thrombosis lead to a stroke?

Answer 6

1. A thrombus (blood clot) formed on an atheroma can break loose creating an embolus and this travels through the blood stream until it blocks a blood vessel.
2. If the blood vessel blocked is in the brain then this may lead to a stroke.
3. Cells are deprived of oxygen leading to death of tissues.

Question 7

What is Peripheral Vascular Disease?

Answer 7

This is the narrowing of the arteries due to atherosclerosis of arteries other than those in the heart or brain.

Question 8

What are symptoms of Peripheral Vascular Disease?

Answer 8

1. Pain when walking (usually the legs are involved) due to limited supply in oxygen.

Question 9

What is Deep Vain Thrombosis (DVT)?

Answer 9

1. The formation of a thrombus in the lower part of the leg in the deep vein resulting in swelling and severe pain.

Question 10

Why can DVT in the leg be fatal?

Answer 10

If the thrombus breaks free to create an embolus this can travel to the pulmonary artery where it can cause a blockage, resulting in chest pain and breathing difficulties. If untreated, this can lead to death.

Question 11

What is cholesterol and where in the body is it found?

Answer 11

It is a type of lipid found in the cell membrane.

Question 12

As well as being a component of the cell membrane, what else is cholesterol used for in the body?

Answer 12

To make sex hormones, testosterone, oestrogen and progesterone.

Question 13

Where does cholesterol in our bodies come from?

Answer 13

1. Cholesterol is synthesised by all cells.
2. 25% of it is made in the liver.
3. A diet high in saturated fats or cholesterol cases an increase in cholesterol levels in the blood.

Question 14

What are HDLs and what do they do?

Answer 14

1. High Density Lipoproteins.
2. They carry cholesterol from the body cells to the liver.
3. High levels of HDL in the blood reduce cholesterol in plaques in the artery walls.

Question 15

What are LDLs and what do they do?

Answer 15

1. Low density lipoproteins.
2. They carry cholesterol from the liver to the body cells.

Question 16

How are cholesterol levels controlled?

Answer 16

1. The production of LDL receptors on cells is controlled by negative feedback.
2. LDL attaches to LDL receptors on cells and cholesterol is passed into the cell.
3. Once the cells has enough cholesterol, LDL receptor production is reduced.

Question 17

Why is excess LDL in the blood not good?

Answer 17

It can deposit cholesterol cholesterol in the arteries forming atheromas.

Question 18

Why is a high ration of HDL:LDL beneficial?

Answer 18

Higher levels of HDL compared to LDL means lower levels of cholesterol circulating in the blood which reduces the development of atherosclerosis.

Question 19

What raises HDL levels?

Answer 19

Regular physical activity.

Question 20

What raises LDL levels?

Answer 20

Eating foods that are rich in cholesterol and saturated fat.

Question 21

Which drugs can be taken to reduce cholesterol levels?

Answer 21

Statins.

Question 22

How do statins work?

Answer 22

They inhibit the synthesis of cholesterol by liver cells.