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Structure of human heart:
The pump on the left deals with oxygenated blood
from the lungs and the right pump deals with deoxygenated blood from the body
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1
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called pulmonary vessels
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The ventricle: has a much thicker muscular wall as
to the four chambers are as follows:
it has to contract strongly to pump blood some
The Aorta is connected to the left ventricle and
distance, either to the lungs or the rest of the
carries oxygenated blood to all parts of the body
body
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Mammals have a system in which the blood is returned
to the heart to increase its pressure before it is distrib- The Vena Cava is connected to the right atrium
uted to the rest of the body
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oxygenated blood in the pump on the left side separate from the deoxygenated blood in the right pump
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The lungs, where its oxygen is replenished and its CO2
thick muscular left wall enables it to contract to create removed
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enough pressure to pump blood to the rest of the
body
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(unusually for a vein it carries oxygenated
vent the backflow of blood into the atria when the
blood)
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There are two valves:
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the left atrioventricular (bicuspid) valve

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The right atrioventricular (tricuspid) valve

Each of the four chambers of the heart is connected to
large blood vessels that carry blood towards or away
from the heart
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The atria receive blood
from the veins
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Blockage of these arteries (like a blood clot) leads to myocardial infarction (heart attack) because an area of the
heart muscle is deprived of blood and therefore oxygen
also
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Smoking:

Blood Cholesterol:

Smokers are between two and six times more likely to suffer
from heart disease than non-smokers
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Its carried in
the plasma as lipoproteins
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Help protect arteries against heart disease
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So it
reduces oxygen-carrying capacity of the blood
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Nicotine: stimulates the production of the hormone adrenaline, which increases heart rate and raises blood pressure =
greater risk of smokers suffering coronary heart disease or a
stroke
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LDLs (low-density lipoproteins) = transport cholesterol
from the liver to the tissues, including artery walls
which they infiltrate leading to the development of
atheroma (may lead to heart disease)
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As there is already a higher pressure in the arteries, the
heart must work harder to pump blood into them and is
therefore more prone to failure
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Higher blood pressure within the arteries means that they
are more likely to develop and aneurysm (weakening of the
wall)
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