3B - Cardiovascular disease

Question 1

What are the coronary arteries?

Answer 1

Blood vessels that branch off the aorta shortly after it leaves the heart that supply oxygen to the heart.

Question 2

What does blockage of the coronary arteries lead to?

Answer 2

Myocardial infarction or heart attack as an area of the heart muscle is deprived of blood and therefore oxygen.

Question 3

Why does myocardial infarction lead to the death of cells in the heart tissue?

Answer 3

Because an area of the heart muscle is deprived of blood and therefore oxygen and so the muscle cells in this region are unable to respire aerobically and so die.

Question 4

What do most cardiovascular diseases start with?

Answer 4

Atheroma formation.

Question 5

How is atheroma formed?

Answer 5

• If damage occurs to the usually smooth and unbroken endothelium by high blood pressure, white blood cells (mostly macrophages) and lipids from the blood, clump together under the lining to form fatty streaks.
• Over time, more WBCs, lipids and connective tissue build up and harden to form a fibrous plaque called an atheroma.

Question 6

What is atheroma?

Answer 6

When WBCs, lipids and connective tissue build up under the endothelium lining and harden to form a fibrous plaque.

Question 7

What do atheromas cause to happen?

Answer 7

Causes the lumen of the artery to become partially blocked which restricts blood flow, causing bp to increase.

Question 8

What is coronary heart disease (CHD) and what can it lead to?

Answer 8

A type of cardiovascular disease which occurs when the coronary arteries have lots of atheroma in them which restricts the blood flow to the heart muscle. It can lead to myocardial infarction (a heart attack).

Question 9

What do atheromas increase the risk of?

Answer 9

Aneurysm and thrombosis.

Question 10

What is an aneurysm?

Answer 10

A disease that affects the arteries - a balloon-like swelling of the artery.

Question 11

What causes an aneurysm?

Answer 11

Atheroma plaques damage and weaken arteries. They also narrow arteries, increasing bp.

When blood travels through a weakened artery at high pressure, it may push the inner layers of the artery through the outer elastic layer to form a balloon-like swelling - an aneurysm.

Question 12

What can happen to an aneurysm?

Answer 12

It may burst, causing a haemorrhage (bleeding).

Question 13

What is thrombosis?

Answer 13

A disease that affects the arteries - the formation of a blood clot.

Question 14

What causes thrombosis to occur?

Answer 14

An atheroma plaque can rupture (burst through) the endothelium of an artery which damages the artery wall and leaves a rough surface. Platelets and fibrin (a protein) accumulate at the site of damage and form a blood clot (a thrombus). Debris from the rupture can cause another blood clot to form further down the artery.

Question 15

What can a thrombus cause to happen?

Answer 15

The blood clot can cause a complete blockage of the artery, or it can become dislodges and block a blood vessel elsewhere in the body.

Question 16

What can cause myocardial infarction?

Answer 16

Interrupted blood flow to the heart.

Question 17

How can interrupted blood flow to the heart cause a myocardial infarction?

Answer 17

Coronary arteries supply the heart muscle with blood containing oxygen needed by the heart muscle cells to respire. If the coronary arteries become blocked completely (e.g. by a blood clot), an area of the heart muscle will be totally cut off from it blood supply and receives no oxygen. This causes a myocardial infarction.

Question 18

What can a heart attack cause?

Answer 18

Damage and death of the heart muscle.

Question 19

What are symptoms of myocardial infarction?

Answer 19

Pain in the chest and upper body, shortness of breath and sweating.

Question 20

What can happen if large areas of the heart are affected by interrupted blood flow?

Answer 20

Complete heart failure can occur which is often fatal.

Question 21

When can complete heart failure occur?

Answer 21

If large areas of the heart are affected by interrupted blood flow - this is often fatal.

Question 22

What factors increase the risk of cardiovascular disease?

Answer 22

High blood cholesterol and poor diet.
Cigarette smoking.
High blood pressure.

Also, being older (age) and being male (sex).

Question 23

How does high blood cholesterol increase the risk of cardiovascular disease?

Answer 23

Cholesterol is one of the main components of the fatty deposits that form atheromas which lead to increased bp and blood clots. This could block the flow of blood to the coronary arteries which would cause a myocardial infarction.

Question 24

What is classed as high blood cholesterol?

Answer 24

Above 240mg per 100cm3.

Question 25

What is a myocardial infarction?

Answer 25

A heart attack.

Question 26

How does a poor diet increase the risk of cardiovascular disease?

Answer 26

A diet high saturated fat is associated with high blood cholesterol levels and a diet high in salt increases the risk of high blood pressure.

Question 27

How does cigarette smoking increase the risk of cardiovascular disease?

Answer 27

Cigarette smoke contains both nicotine and carbon monoxide.

Nicotine increases the risk of high blood pressure.

Carbon monoxide combines with haemoglobin and reduces the amount of oxygen transported in the blood, reducing the amount of oxygen available to the tissues. which could lead to a heart attack.

Smoking also decreases the amount of antioxidants in the blood so the cells aren’t protected as well from damage so cell damage in the coronary artery walls is more likely, and this can lead to atheroma formation.

Question 28

How does high blood pressure increase the risk of cardiovascular disease?

Answer 28

It increases the risk of damage to the artery walls meaning there is an increased risk of atheroma formation causing a further increase in bp. These atheromas can also cause blood clots to form which could block the flow of blood to the heart muscle which may result in a myocardial infarction.