Cardiovascular Disease

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Cardiovascular Disease

Cardiovascular diseases are diseases linked to the cardiovascular

system.

Atherosclerosis means hardening of arteries and it’s a build up of

fatty deposits (plaques) in the arteries

A plaque can build up until it restricts it blood flow partially or

completely.

Plaques are more likely to form in the (coronary arteries of the heart)

and the (carotid arteries of the neck)

Arteries over veins:

atherosclerosis is more likely to happen in the arteries rather than

the veins

This is because the blood in the arteries flow fast under high

pressure this puts more strain on the endothelium layers which can cause small

areas of damage.

The veins are under lower pressure so damage to the endothelium is

less likely to happen

The events that lead to atherosclerosis:

1)

The endothelium

layer is usually smooth and unbroken. Damage to the endothelial lining of the

blood leads to the formation of plaque and this can be caused by many factors

such as High blood pressure and chemicals In tobacco smokers

2)

Once the damage

has occurred the body inflammatory response begins. White blood cells (mostly

macrophages) arrive at the site of the damage. These cells accumulate chemicals

in the blood, particularly cholesterol. This leads to a fatty deposit called

atheroma forming in the endothelial lining of the artery.

3)

Fibrous tissues

and calcium salts build up around the fatty deposit, turning it into hardened

plaque. This means that artery walls will harden so its less elastic. This is

atherosclerosis.

Effect of atherosclerosis:

Lumen becomes smaller due to

plaque

This increases blood

pressure, making it harder to pump blood around the body.

This increases the blood

pressure making it harder to pump blood around the body. This increased blood

pressure most likely will cause damage to the endothelium layer in other areas.

This will cause the

formation of more plaque and will lead to and even higher blood pressure.

Heart Disease:

There are many but the two

main ones are angina and myocardial infraction (heart attack)

Both are related to atherosclerosis

Myocardial Infraction:

If one of the branches of

the coronary arteries becomes blocked part of the heart muscle will be starved

of oxygen (for respiration) and the person will have a heart attack.

Many heart attacks are

caused by blood clots due to atherosclerosis

1)

The wall

affected by the plaque is stiff making it more easy to crack or get damaged

2)

An atheroma can

rupture (burst through) the endothelium layer on an artery leaving a damaged

and rough surface

3)

Platelets come

in contact with the damages surface of the plaque and clotting is triggered

4)

Or the plaque

itself may break open and release cholesterol which when comes in contact with platelets

will cause clotting

5)

A clot may

simply happen because the endothelial lining is damaged

6)

A clot in the

blood is called a thrombosis

7)

This clot can

rapidly block the whole blood vessel, particularly narrowed by plaque. The blood clot can become dislodged and block

a vessel somewhere else in the body.

8)

A clot that gets

stuck in the coronary artery is called coronary thrombosis

9)

The clot can

block the artery starving the heart muscle of oxygen and nutrients

Leading

to a heart attack.

10)

A heart can cause

death and the death of the heart muscle

11)

Symptoms include

pain in the chest and upper body, shortness of breath and sweating

12)

If large areas

are affected it can lead to heart failure

Strokes:

A stroke is caused by an

interruption of blood supply to the brain. This comes from a blood clot, an

atheroma or combination

Sometimes blood clots form

somewhere else then is carried in the blood to get stuck in the brain artery.

This means less oxygen

Damage happen quickly

A block to a main artery can

lead to serious stroke and even death

Factors that can increase

the risk of cardiovascular disease:

Age:

A you get older your blood

vessels start to get les elastic and narrow making you more likely to suffer

from CVD. Specially heart disease. When its less elastic there will be higher

pressure during systole. This will lead

to hypertension (abnormal high pressure). So more atherosclerosis

Gender:

Men are more likely to

suffer.

The female hormone

osterogen, which plays an important role in the women menstrual cycle, appears

to reduce plaque. This gives them protection till menopause.

Women have less stressful

jobs so less hypertension

Genes:

Some people inherit

particular alleles. Some genetics may cause arteries to be more easily damaged,

which will make them more likely to get (hypertension) high blood pressure or

high blood cholesterol, so more likely to suffer from CVD

Hypertension:

This increases the risk of

damage to the artery walls; this increases the risk of atheroma, which can lead

to CVD

Excessive alcohol

consumption, stress and diet can all increase blood pressure

Diet:

A diet in saturated fat

increases CVD

This is because of the

increase of blood cholesterol level, which leads to atheroma formation.

Atheroma can lead to blood clot= leads to heart attack or stroke.

A diet high in salts also

increases CVD because it increases the risk of high blood pressure

Alcohol causes hypertension.

Eating more calories causes

BMI to increase. Associated to Atheroma.

Smoking:

Chemicals in tobacco cause

damage to the lining of the arteries, making it build up plaque more likely

Causes arteries to narrow,

raising blood pressure and increasing risk of CVD

CO mixes with hemoglobin and

this reduces the amount of oxygen transported in the blood. This reduces the

amount of oxygen available to the tissue. If the heart doesn’t receive enough

oxygen it will get a heart attack. If the brain doesn’t receive enough oxygen

it will lead to a heart attack.

Nicotine makes platelets

sticky, increasing the chance of blood clot forming, increases CVD

Smoking decreases amount of

antioxidants in the blood – these are important for protecting cells from

damage. Fewer antioxidants means cell damage in the artery walls and can lead

to atheroma formation = increase risk of CVD

Inactivity-

Lack of exercise increases

risk of CVD because it increases blood pressure

Lower BMI = less

hypertension

Fitter heart = less

hypertension

Exercises decreases LDL

levels

Exercise increases metabolic

rate, which means lower BMI

High blood cholesterol

increases CVD

Cholesterol is a lipid made

in the body

Some is needed for the body

to function normally

Cholesterol needs to be

attached to a protein to be moved so the body forms lipoproteins, made of

lipids and proteins

High saturated fats = high cholesterol

levels = cholesterol is in plaque so form

atherosclerosis

Two types of lipoproteins:

HDL:

Formed by unsaturated fats,

cholesterol and protein

They carry cholesterol from

your body tissues to your liver where it is broken down, lowering cholesterol

levels

HDL can also help to remove

cholesterol from fatty plaques on the arteries, reducing the risk of heart

diseases from atherosclerosis. Their function is to decreases blood cholesterol

when it’s too high.

LDL:

Are formed from saturated

fats, cholesterol and protein

They carry more cholesterol

that HDLs and bind to cell membranes after being taken to the cells. If LDL

levels are too high, your cell membranes become saturated and more LDL

cholesterol is left in the body

They carry cholesterol from

liver to blood

This function is to increase

blood cholesterol when it is too low.

High total blood cholesterol

level (the level of HDL, LDL and other cholesterol )and high LDL level have

both been linked to an increased risk of CVD.

A diet high in saturated

fats raises LDL levels, so more cholesterol is transported to the blood,

increasing total blood cholesterol increasing risk of CVD

A diet high in polysaturated

fat (corn oil, sunflower oil oily fish) mainly HDL – so more cholesterol is

transported from the blood to the liver. This decreases total blood cholesterol

level decreasing the risk of CVD

Drugs which are used to

treat CVD

Antihypertensive: All of these reduce blood pressure, so

there is less damage to the artery walls.

This reduces atheroma forming and blood clots.

Diuretics

– The Loop of Henle is the part of the nephron (in the kidney)

that regulates water reabsorption. Essentially, it puts Na+ back into the

blood by active transport. This lowers the water potential in the blood, so

water follows the Na +

By osmosis. Most diuretics block the protein that actively

transports the Na +, so less water is returned to the blood, thus reducing the

pressure. This means more urine Is produced.

This gets rid of excess salts and fluids. Dp the blood volume falls.

With less blood, a smaller volume is pumped from the heart and the blood

pressure falls. Three problems with this. The blood gets more viscous, which

makes the heart beat harder. Dehydration can occur. Only treating the symptom.

Beta Blockers.

They block the response of the heart to hormones such as

adrenaline, which normally speed up the heart and increase blood pressure. So

beta blockers makes the heart rate slower and contraction less strong, so the

blood pressure is lower

Vasodilators: Widen blood

vessels

Sympathetic nerve inhibitors:

Affect the sympathetic nerve

from your central nervous system to all parts of your body

Sympathetic nerves stimulate

your arteries to constrict, which in turn raises your blood pressure. The inhibiters

prevent these signaling to the arteries, which helps to keep them wide and keep

blood pressure low

Angiotensin is a hormone,

which stimulates the constriction of your blood vessels and so causes the blood

pressure to rise. ACE inhibitors block the production of angiotensin, reducing

the constriction of your blood vessels and you blood pressure lower.

Benefits:

The different types of drugs

work in different ways, so they can be in a combination to reduce blood

pressure.

The risk of CVD is decreases

Damage to the kidneys and

eyes from high blood pressure decreases

Risks:

If not monitored carefully

blood pressure can fall too low, which can lead to falls and injuries

Has a side effect:

Palpitations (rapid beating

of the heart)

Abnormal heart rhythms

Swelling of ankles

Impotence and tiredness

Fainting

Headaches

Allergic reactions

Depression

Plant statins:

Statins are a group of drugs

that lower the level of cholesterol in your blood. They block the enzyme in the

liver that is responsible for making cholesterol. More effective in stopping the

creation of LDL. They improve the balance of LDLs and HDL and reduce

inflammation in the lining of the arteries. Both of these functions reduce the

risk of atherosclerosis.

* Plants contain chemicals

called stanols and sterols. They are referred to as plant statins. Sold in

spreads and yogurts. They reduce the amount of cholesterol absorbed in the gut

into your blood, which makes it easier for your body to deal with cholesterol

and reduce the levels of LDLs in the blood. A lower blood cholesterol level reduces

atheroma formation, which reduces the risk of CVD. To consume enough plant statins

you’d have to eat lots of plants but now can be found in foods such as some

margarine.

Benefits:

Statins reduce the risk of

developing CVD

Risks

Reduce the absorption of

some vitamins

Anticoagulants:

Anticoagulants (e.g.

warfarin, heparin) help to reduce blood clotting. It interferes with the

manufacture of prothrombin in the body. Low prothrombin levels make the blood

clot less easily. This means blood clots are less likely to form at sites of

damage artery walls. So less chance of blocking a blood vessel. This reduces

CVD.

Benefits:

Used to treat people who

already have blood clots or CVD

They prevent existing clots

from growing any larger

Prevent new clots from

forming

Can’t get rid of existing

blood clots

Risks

If someone badly injured the

reduction in blood can cause escssive bleeding, lead to fainting and even death

Allergic reactions and

osteoporosis and tissue swelling

Drugs may damage fetus

Platelets inhibitor drugs

(Eg aspirin) are a type of

anticoagulant, which makes platelets less sticky, so reduces the blood clotting

ability. This stops them from clumping together so less chance a blood vessel

gets blocked.

Benefits:

Can be used to treat someone

who already has blood clots and CVD

Risks:

Rashes,

Diarrhea

Nausea

Live function problems and

excessive bleeding