2.7 - Pathology Of Cardiovascular Disease

Question 1

Atherosclerosis

Answer 1

Atherosclerosis is the accumulation of fatty materials (consisting mainly of cholesterol, fibrous material and calcium) forming an atheroma or plaque beneath the endothelium of an artery.

Question 2

Impact of atheroma on artery

Answer 2

As the atheroma grows, the artery thickens and loses its elasticity. The diameter of the lumen becomes reduced and bloodflow becomes restricted resulting in increased blood pressure

Question 3

What is atherosclerosis the root cause of

Answer 3

Atherosclerosis is the root cause of various cardiovascular diseases (CVD) such as angina, heart attack, stroke and peripheral vascular disease.

Question 4

What is angina

Answer 4

Angina is chest pain caused by reduced bloodflow to the heart muscles and is usually caused by coronary heart disease.

Question 5

Cardiovascular disease – atheroma

Answer 5

Atheromas may rupture leading to damage to the endothelium. This damage releases clotting factors that activate a cascade of reactions that cause a blood clot called a thrombus.

Question 6

What is thrombosis

Answer 6

Formation of a thrombus

Question 7

What does the damage to the endothelium release

Answer 7

The damage to the endothelium releases clotting factors that activate a cascade of reactions resulting in the conversion of the enzyme prothrombin to its active form from thrombin.

Question 8

What does thrombin cause

Answer 8

Thrombin causes molecules of the plasma protein fibrinogen to form threads of fibrin. The fibrin threads form a mesh work that clots the blood, seals the wound and provides a scaffold for the formation of scar tissue.

Question 9

What is clotting

Answer 9

Clotting is the mechanism that prevents blood loss from broken blood vessels

Question 10

What can a thrombosis lead to

Answer 10

A thrombosis in a coronary artery may lead to a myocardial infraction, commonly known as a heart attack

Question 11

What leads to a stroke

Answer 11

A thrombosis in an artery in the brain may lead to a stroke. Cells are deprived of oxygen leading to death of the tissues.

Question 12

How is an embolus formed

Answer 12

In some cases, a thrombus may break loose forming an embolus which travels through the bloodstream until it blocks a blood vessel.

Question 13

Stroke

Answer 13

The brain cells need a constant supply of oxygen from the blood.

A stroke means that the blood supply to a part of the brain is suddenly cut off.

Soon after the blood supply is cut off, the cells in the affected area of the brain become damaged or die.

Question 14

What causes peripheral vascular disease

Answer 14

Peripheral vascular disease is caused by narrowing of the arteries due to atherosclerosis of the arteries other than those of the heart and brain.

Question 15

Peripheral vascular disease - what arteries are most commonly affected

Answer 15

The arteries in the legs are most commonly affected.

Pain is experienced in the leg muscles due to a limited supply of oxygen.

Question 16

What is a deep vein thrombosis (DVT)

Answer 16

A deep vein thrombosis is a blood clot that forms in a deep vein most commonly in the leg.

These break off and result/cause a pulmonary embolism.

Question 17

What causes a pulmonary embolism

Answer 17

A pulmonary embolism is caused when an embolus blocks the pulmonary artery.

This results in chest pain and breathing difficulties.

Question 18

What is cholesterol

Answer 18

Cholesterol is a fatty substance known as a lipid found in the cell membrane.

It is necessary for normal functioning of the body.

Question 19

What is cholesterol also used for

Answer 19

Make sex hormones - testosterone, oestrogen and progesterone

Question 20

Where is cholesterol made

Answer 20

Cholesterol is synthesised by all cells, although 25% of total production takes place in the liver

Question 21

What causes an increase in cholesterol levels in the blood

Answer 21

A diet high in saturated fats or cholesterol

Question 22

How is cholestrol transported

Answer 22

Carried in the blood by proteins.

It combines with proteins and forms lipoproteins. (Which is what is carried in the blood)

Question 23

Types of lipoprotein

Answer 23

High density lipoprotein - HDL.

Low density lipoprotein- LDL

Question 24

HDL function

Answer 24

HDL transports excess cholesterol from the body cells to the liver for elimination which prevents the accumulation of cholesterol in the blood.

Question 25

LDL function

Answer 25

LDL transports cholesterol to body cells

Question 26

LDL receptors and cells

Answer 26

Most cells have LDL receptors that take LDL into the cell where it releases cholesterol. Once a cell has sufficient cholesterol, a negative feedback system inhibits the synthesis of new LDL receptors and LDL circulates in the blood where it may deposit cholesterol in the arteries forming atheromas.

Question 27

HDL to LDL ratio

Answer 27

A higher ratio of HDL to LDL will result in lower blood cholesterol and reduced chance if atherosclerosis.

Question 28

What causes an increase in blood

cholesterol levels

Answer 28

A diet high in saturated fats or cholesterol

Question 29

What raises HDL

Answer 29

Regular physical activity

Question 30

What do dietary changes aim to do?

Answer 30

Reduce the levels of total fat in the diet and to replace saturated with unsaturated fats.

Question 31

Drugs and cholesterol levels

Answer 31

Drugs such as statins reduce blood cholesterol by inhibiting the synthesis of cholesterol by liver cells.