Coronary Heart disease 3.1.5(text p.94)

Atheroma as the presence of fatty material within the walls of arteries.

The link between atheroma and the increased risk of aneurysm and thrombosis

Syllabus

What is coronary heart disease?Coronary heart disease (CHD) is a disease of the arteries supplying the heart (coronary arteries). Almost one-fifth of all deaths in the UK in 2005 were due to CHD.

The major cause of CHD is atherosclerosis: a thickening of arteries caused by a build-up of fatty plaques (atheromas) on the inside walls.

Atherosclerosis can eventually lead to a reduced blood supply (ischaemia) to tissues, with potentially fatal consequences.

Effects of CHD: heart attackThe most dangerous symptom/result of CHD is a heart attack, known as a myocardial infarction (MI).

An MI occurs when the blood supply to part of the heart muscle (myocardium) is interrupted. This causes oxygen deprivation and subsequent tissue damage.

The most common symptom ischest pain, but shortness of breath, excessive sweating, nausea and weakness may also be present. Loss of consciousness and death can occur.

Key words – match the definition;

• Coronary heart disease• Coronary artery• Atheroma• Myocardial infarction

1. The small artery serving the ventricles cardiac muscle

2. The presence of fatty material within the coronary arteries

3. The disease where the coronary arteries get blocked

4. blood cannot reach the cardiac muscle cells not enough oxygen die and stop contracting heart attack CELLS CANNOT RESPIRE

Development of atherosclerosis

Stages

How atheroma can cause a myocardial infarction

Coronary artery magnified

Atheroma – fatty material within the wall Below the endothelial cells

Endothelial cells

Myocardial infarction – blood cannot reach the cells not enough oxygen stop respiration ventricular systole stops

The link between atheroma and thrombosis

Thrombosis is a blood clot

a through-and-through rupture (break through) of the plaque’s fibrous cap which blood cells stick to forming the clot

the endothelial cells becoming rough so blood cells stick to it right panel

The link between atheroma and risk of aneurysm

• Atheroma can weaken artery walls

• The weakened points lose their elasticity and swell (like a balloon which has been over inflated)

• This is called an aneurysm• They can burst causing

internal bleeding

How does CHD develop?

Risk factors

• Smoking• Diet • High blood pressure• Blood cholesterol

others: stress, alcohol

diabetes mellitus

obesity

ethnicity/racephysical inactivity

family history of the diseasetobacco smoking

male genderhigh blood cholesterol

advancing agehigh blood pressure

CHD risk factorsHundreds of risk factors for CHD and stroke have been identified. The major ones are:

Non-modifiableModifiable

How Smoking increases risk of CHDSmoking tobacco is a major cause of CHD, and smokers are at a higher risk of developing CVD than lung cancer.

Smoking increases the risk of CHD in several ways:

it damages and weakens the endothelial lining of blood vessels

nicotine increases blood pressure and heart rate, by constricting blood vessels

it increases clotting and the development of atheromas

carbon monoxide reduces the amount of oxygen that blood can carry by binding to haemoglobin

it lowers HDL cholesterol and raises LDL cholesterol levels

• Nicotine makes red blood cells more sticky leading to a higher risk of thrombosis e.g. Strokes or MI

• Smoking can decrease antioxidants in the blood. Antioxidants reduce risk of heart disease (Dietary fibre, Vitamin C)

How Smoking increases risk of CHDSmoking tobacco is a major cause of CHD, and smokers are at a higher risk of developing CVD than lung cancer.

Smoking increases the risk of CHD in several ways:

it damages and weakens the e…………. lining of blood vessels

nicotine increases b….. p..……. and heart rate, by constricting b…. V……

it increases c……… and the development of a……………..

carbon monoxide reduces the amount of oxygen that blood can carry by binding to h……….

it lowers … cholesterol and raises … cholesterol levels

• Nicotine makes red blood cells more s….. leading to a higher risk of thrombosis e.g. strokes or MI

• Smoking can decrease a……….. in the blood. Antioxidants reduce risk of heart disease (Dietary fibre, Vitamin C)

Cholesterol and lipoproteinsCholesterol is a soft waxy lipid that has a vital role as a component of cell membranes, where it regulates fluidity.

Cholesterol is insoluble in blood, so it is transported by lipoproteins. These are spherical complexes consisting of:

Two major types of lipoprotein are low-density lipoprotein (LDL) and high-density lipoprotein (HDL).

an outer layer of phospholipids, studded with proteins

an inner core of trigylcerides and cholesterol.

High blood cholesterol levels and CHDLDLs generally transport cholesterol from the liver to body tissues, depositing it on thewalls of blood vessels. In high levels,it contributes to atherosclerosis.

HDLs generally transport cholesterol away from the tissues to the liver, where the cholesterol is metabolized. High levels of HDL cholesterol are linked to a reduced risk of CHD.

Eating a diet high in saturated fat is the biggest cause of elevated LDL cholesterol levels.

LDL cholesterol levels can be reduced by regular exercise, eating plenty of fibre and a diet rich in polyunsatured fats.

How a diet high in saturated fat increases the risk of myocardial infarction

• Saturated fat increases the …. density lipoprotein levels in the blood

• These transport c………. from the l…. to the tissues including the artery walls

• A……. may form• Blood pressure may be increased • Blood clot may occur• Blocks flow of blood to heart in coronary arteries• (…. density lipoproteins in the blood remove

cholesterol from tissues and deposits it safely in the liver protecting from heart disease)

How a diet high in saturated fat increases the risk of myocardial infarction

• Saturated fat increases the low density lipoprotein levels in the blood

• These transport cholesterol from the liver to the tissues including the artery walls

• Atheroma may form• Blood pressure may be increased • Blood clot may occur• Blocks flow of blood to heart in coronary arteries• (high density lipoproteins in the blood remove

cholesterol from tissues and deposits it safely in the liver protecting from heart disease)

High blood pressure and CHDHigh blood pressure (hypertension) is a major risk factor for CHD and other cardiovascular diseases.

Hypertension is defined as systolic blood pressure above 140 mmHg and/or diastolic blood pressure above 90 mmHg.

Hypertension puts strain on the heart and blood vessels, increasing the risk of aneurysm or thrombosis. It is sometimes called the ‘silent killer’ because it can develop without symptoms.

Hypertension and CHD

How high blood pressure can increase the risk of heart disease

Factors which can lead to high blood pressure are1.G…… …. …….2.S………3.Poor ……..4.Lack of ………………

How high blood pressure causes heart disease1.Heart has to work harder to move high pressure blood. Strains it2.High blood pressure in artery more chance of a…….3.Walls of arteries may h….. as a response resisting flow of blood further

How high blood pressure can increase the risk of heart disease

Factors which can lead to high blood pressure are1.Genetic make up2.Stress3.Poor diet4.Lack of exercise

How high blood pressure causes heart disease1.Heart has to work harder to move high pressure blood. Strains it2.High blood pressure in artery more chance of aneurism3.Walls of arteries may harden as a response resisting flow of blood further

Trends in CVD death rates

Identifying CHD risk factors

Questions

• Text p.96 red• Text p.97 green• Text p.98-99