Key Area 7- Pathology of Cardio Vascular Disease (CVD)

Question 1

What is atherosclerosis?

Answer 1

The accumulation of fatty material, consisting mainly of cholesterol, fibrous material and calcium, which forms a plaque, which is called an atheroma, which forms beneath the endothelium

Question 2

What is atheroma?

Answer 2

A plaque which forms beneath the endothelium due to atherosclerosis

Question 3

What happens over time to the atheroma?

Answer 3

It may grow, causing the plaque to become enlarged as fibrous material, calcium and more cholesterol are added, which makes the atheroma larger.

Question 4

What are the consequences of the atheroma?

Answer 4

. As the atheroma grows, the artery thickens and loses its elasticity
. The diameter of the artery’s lumen is reduced
. Blood flow becomes restricted to the capillary bed that the artery supplies
.Increased blood pressure
. Hardening of the arteries

Question 5

What cardiovascular diseases is atherosclerosis the root cause of?

Answer 5

Angina, heart attack, stroke and peripheral vascular disease

Question 6

How is a thrombus formed?

Answer 6

An atheroma on the inside lining of an artery may rupture, which damages the endothelium and leads to the formation of a thrombus.

Question 7

What is the first step in the formation of a thrombus?

Answer 7

If an atheroma ruptures and damages the endothelium then, blood clotting factors, which is a protective device to prevent the loss of blood at a wound, are released. This activates a cascade of reactions resulting in the conversion of the enzyme prothrombin into thrombin

Question 8

What is the second step in the formation of a thrombus?

Answer 8

Thrombin causes molecules of fibrinogen, a plasma protein, to form threads of fibrin

Question 9

What is the third step in the formation of a thrombus?

Answer 9

Fibrin threads from a meshwork that clots the blood, and seals the wound providing a scaffold for the formation of scar tissue

Question 10

What is the formation of a thrombus/clot called?

Answer 10

Thrombosis

Question 11

What is an embolus?

Answer 11

If the thrombus breaks lose and form an embolus, which travels down the bloodstream until it blocks a blood vessel and restricts blood flow

Question 12

What can thrombosis in a coronary artery lead to?

Answer 12

It may lead to a heart attack, myocardial infarction, because it blocks the coronary artery

Question 13

What can thrombosis the brain lead to?

Answer 13

A stroke, if it causes blockages in an artery to the brain

Question 14

What happens if cells in the brain are deprived of oxygen?

Answer 14

Brain tissues can die

Question 15

What is peripheral vascular disease?

Answer 15

The narrowing of the arteries, of arteries other than those to the heart and the brain, due to atherosclerosis

Question 16

What arteries are most commonly affected by peripheral vascular disease?

Answer 16

Arteries to the legs. The blood flow to the legs is restricted and pain is felt due to a limited supply of oxygen reaching the leg muscles

Question 17

What is a deep vein thrombosis (DVT)?

Answer 17

A blood clot/thrombus that forms in a deep vein, most commonly in the leg.

Question 18

What does DVT cause?

Answer 18

It causes the area to be painful, swell up and veins close to the skin surface can become engorged with blood

Question 19

What happens if the deep vein thrombosis breaks off?

Answer 19

The blood clot can break off and travel through the blood stream and result in a pulmonary embolism in the lungs as the embolus/blood clot can block a pulmonary artery

Question 20

What can a pulmonary embolism cause?

Answer 20

Chest pains, breathing difficulties and palpitations

Question 21

What are lipids?

Answer 21

They are a diverse group of organic compounds which include simple lipids, such as fats, and more complex lipids, such as steroids

Question 22

Where is cholesterol located?

Answer 22

Its located in the cell membrane

Question 23

Why is cholesterol important?

Answer 23

Because it is needed for the synthesis of the sex hormones testosterone, oestrogen and progesterone

Question 24

What are lipoproteins?

Answer 24

They are molecules containing a combination of lipid and protein

Question 25

Where are lipoproteins found?

Answer 25

They are found in the blood plasma which transports the lipids from one part of the body to another

Question 26

What are the two major transport lipoproteins?

Answer 26

High density lipoproteins (HDL) and low density lipoproteins (LDL)

Question 27

What do HDL’s transport and what does this prevent?

Answer 27

They transport excess cholesterol from the body tissues to the liver to be broken down and eliminated. This prevents the accumulation of cholesterol in the blood, which lowers blood cholesterol levels and helps remove plaque so doesn’t contribute to atherosclerosis
.They are known as ‘good cholesterol’

Question 28

What are LDL’s produced by?

Answer 28

The liver

Question 29

What do most cells have?

Answer 29

LDL receptors which take LDL into the cell where it releases cholesterol

Question 30

What is the negative feedback control of LDL’s?

Answer 30

. If a cell has sufficient cholesterol, a negative feedback system is triggered which inhibits the synthesis of new LDL receptors
.LDL circulates in the blood where it may deposit in the arteries forming atheromas

Question 31

What will a higher ratio of HDL to LDL result in?

Answer 31

A lower blood cholesterol and a reduced chance of atherosclerosis

Question 32

What are the treatments for raising HDL levels and lowering LDL levels?

Answer 32

. Dietary changes which aim to reduce the levels of total fat in the diet and to replace saturated fats with unsaturated fats
. Regular physical activity tends to raise HDL levels

Question 33

What are drugs for rasing HDL levels and lowering LDL levels?

Answer 33

. Reducing blood cholesterol through prescribed medications
. Drugs such as ‘statins’ reduce blood cholesterol by inhibiting the synthesis of cholesterol by liver cells